Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the...

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Ductile Deformation(韌性變形) Mechanisms Earth Science Picture of the Day: http://epod.usra.edu/ North-verging (向北 伸向) recumbent fold (偃臥摺皺) in Mesozoic rocks of the Morcles thrust; Swiss Alps Jyr-Ching Hu, Department of Geosciences National Taiwan University Dent (牙齒) De Morcles

Transcript of Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the...

Page 1: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Ductile Deformation(韌性變形) Mechanisms

Earth Science Picture of the Dayhttpepodusraedu

North-verging (向北伸向) recumbent fold (偃臥摺皺) in Mesozoic rocks of the Morcles thrust Swiss Alps

Jyr-Ching Hu Department of GeosciencesNational Taiwan University

Dent (牙齒) De Morcles

How can a strong layer of rock permanently bend into a tight fold

httpepodusraedu

Dent (牙齒) De MorclesIt was taken in the PenninesAlps of SW Switzerland and shows a portion of a geological formation known as the Dent de Morcles The Morcles is a classic alpine nappe structure A nappe is a large plate of rocks moved from its place of orgin by faulting or folding The rocks (mostly limestone) in the recumbent folds of the Dent de Morcles have been turned nearly up side down These rocks date from the Mesozoic Era (65-245 my ago)

Three fundamental mechanisms

(1) Cataclastic flow (破裂與碎屑流)

(2) Diffusional mass transfer (物質擴散性轉移)

(3) Crystal plasticity (晶體塑性流動)

Which process dominate at a given time in a rockrsquos deformation history

bull Temperature (溫度)bull Stress (應力) bull Strain rate (應變速度) bull Grain size (顆粒尺寸) bull Composition (成分) bull Fluid content (流體含量)

Homologous temperature (溫度指標)

bull Homologous temperature A dimensionless parameter defined as the absolute temperature divided by the absolute melting temperature of the material (Th=TTm temperature in K)

bull Low-temperature condition 0 lt Th lt 03bull Medium -temperature condition 03 lt Th lt 07bull High-temperature condition 07 lt Th lt 1

Cataclastic flow (碎屑流動) Bean bag experiment

Such a process where a mesoscopic body (the bean bag) changes shape without breaking into separate pieces but the constituents (the beans) fracture into smaller pieces andor pass one another

Cataclastic Flow (碎屑流動)bull In rocks the tiny structures are called microcracks

and the pieces of move past one another by the process of frictional sliding (克服摩擦力的滑動)

bull During cataclastic flow a rock deforms without obvious strain localization (應變集中) on the scale of hand specimen yet the mechanism of deformation is (micro)fracturing andor friction sliding

bull Cataclasis is mesoscopic ductile behavior (韌性變形行為) yet the process by which it occurs is microscopic brittle fracturing (脆性的顆粒破碎作用)and frictional sliding

Cataclastic Flow (碎屑流動)

bull 破碎岩(cataclastic rock)一旦形成之後這些破碎顆粒會因為斷層的再度活動而以破碎作用顆粒間的摩擦滑動剛體旋轉的方式流動這種流動稱為碎屑流動破碎流動很像未固結沈積物的顆粒流動(granular flow)但差別在於

1 顆粒流動時大部分的的顆粒並未進一步地破碎而破碎流動則是大部分的顆粒會進一步地變得更為破碎

2 顆粒流動只有在顆粒邊界的強度小於顆粒本身的強度內聚力很小而且圍壓很小時才會產生而破碎流動則是在軸差應力超過岩石顆粒的強度時才能產生

Cataclasite (破碎岩)

bull Thin section (crossed polars quartz plate) of cataclasite with angular broken fragments of quartz and feldspar in a very fine-grained matrix of phyllosilicate minerals and quartz powder Nelsprint E Transvaal S Africa RampH photo

Cataclastic rock (破碎岩)

(照片寬度為02 mm) Courtesy of Prof Yang Chao-Nan

Crystal Defects (晶體缺陷)

bull Ductile behavior (韌性行為) of materials at elevated temperature by the motion of crystal defects

bull A crystal defect is an error in the crystal lattice there are three basic types(1) Point defects (點缺陷)(2) Line defects (線缺陷) or dislocations (差排)(3) Planar defects (面缺陷) or stack faults

Crystal Defects (晶體缺陷)bull The motion of defects give rise to permanent

strain without the material losing cohesion (ie without fracturing)

bull Point and line defects are most important for the deformation of rock

bull Planar defects which arise from errors in the internal layering of minerals play only a limited role in deformation

Point defects

(a) Vacancies (空缺)

(b) Substitution (替代雜質)

(c) Interstitials (間隙雜質)

(d) Vacancy migration (空缺遷移)Diffusion

Diffusion (擴散作用)

bull Vacancies can migrate by exchange with atoms in neighboring sites

bull When an atoms moves into a vacant site you can equally say that the vacancy moved

Line Defects or DislocationsDislocation line The boundary between the unslippedand sipped portion of the crystal

Edge dislocation (刃差排)

Screw dislocation(螺旋差排)

Edge dislocation (刃差排)bull Occurs where there is an extra half-plane (多半面) of atoms

in the crystal latticebull Symbol for edge location is or depending on whether

the location of the extra half-plane is above or below the associated gliding plane of the crystal

Screw dislocation (螺旋差排)

bull Atoms are arranged in a corkscrew-like fashion the axis of the screw marks the dislocation line (line CD)

Burgers vector (Burgers 向量)

bull In a deformed crystal an atom-by-atom circuit around the dislocation fails to close by one or more atomic distances while a similar circuit around atoms in a perfect crystal would be complete The arrow connecting the two ends of the incomplete circuit is called Burgers vector

bull The length of Burgers vector in most minerals is on the order of nanometers

Determination of the Burgers vector (伯格向量)

(1) b perpendicular to l(2) Burgers cricuit

remain in the same plane

柏格環路

Determination of the Burgers vector (伯格向量)

(1) b and l are parallel(2) Potential slip plane(3) Glide plane

crystallogrphic plane

柏格環路 Table 91

Mixed dislocations (混合差排)

bull Edge and screw dislocations are only end-member geometries (perfect dislocation) dislocations that consists of part edge and part screw components are called mixed dislocation

Dislocation in olivine

Stress field around an edge dislocation

Wood-split analogy

Shear stress

Interactions between neighboring edge dislocation

(b) Like dislocation on widely separated glide planes may attract or repel depending on the angle between the lines joining the dislocation

(c) Unlike dislocation on the same or nearby glide planes attract

(a) Like dislocation on the same or nearby glide planes repel

Crystal Plasticity (晶體的塑性流動)

bull Dislocation are able to migrate through the crystal lattice if the activation energy (活化能) for movement is achieved

bull Distortion of crystal lattice around the dislocation is one source of driving energy as the system tries to achieve a lower internal strain energy

bull Applying a differential stress is another driving mechanism for dislocation motion

Crystal Plasticity (晶體的塑性流動)

bull Associated distortion of solid phases is called crystal plasticity

bull Dislocation movement may occur by glide and a combination of glide and climb (creep)depending mainly on temperature

bull Twinning (双晶 crystal-plastic behavior)occurs at low temperature in some minerals

Crystal Plasticity (晶體的塑性流動)

(1) Dislocation Glide (差排滑動)(2) Cross-slip and climb (側向滑動與爬升) (3) Mechanical Twinning (機械性的雙晶作用)

Dislocation glide (差排滑動)

Dislocation glide(差排滑動)

bull At low temperature dislocations are restricted to glide planes (or slip planes) The glide plane of a dislocation is the plane that contains the Burger vector (b) and the dislocation line (差排線 l) Each edge dislocation has one slip plane because b and l are perpendicular

bull A screw dislocation has many potential slip planes because b and l are parallel

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 2: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

How can a strong layer of rock permanently bend into a tight fold

httpepodusraedu

Dent (牙齒) De MorclesIt was taken in the PenninesAlps of SW Switzerland and shows a portion of a geological formation known as the Dent de Morcles The Morcles is a classic alpine nappe structure A nappe is a large plate of rocks moved from its place of orgin by faulting or folding The rocks (mostly limestone) in the recumbent folds of the Dent de Morcles have been turned nearly up side down These rocks date from the Mesozoic Era (65-245 my ago)

Three fundamental mechanisms

(1) Cataclastic flow (破裂與碎屑流)

(2) Diffusional mass transfer (物質擴散性轉移)

(3) Crystal plasticity (晶體塑性流動)

Which process dominate at a given time in a rockrsquos deformation history

bull Temperature (溫度)bull Stress (應力) bull Strain rate (應變速度) bull Grain size (顆粒尺寸) bull Composition (成分) bull Fluid content (流體含量)

Homologous temperature (溫度指標)

bull Homologous temperature A dimensionless parameter defined as the absolute temperature divided by the absolute melting temperature of the material (Th=TTm temperature in K)

bull Low-temperature condition 0 lt Th lt 03bull Medium -temperature condition 03 lt Th lt 07bull High-temperature condition 07 lt Th lt 1

Cataclastic flow (碎屑流動) Bean bag experiment

Such a process where a mesoscopic body (the bean bag) changes shape without breaking into separate pieces but the constituents (the beans) fracture into smaller pieces andor pass one another

Cataclastic Flow (碎屑流動)bull In rocks the tiny structures are called microcracks

and the pieces of move past one another by the process of frictional sliding (克服摩擦力的滑動)

bull During cataclastic flow a rock deforms without obvious strain localization (應變集中) on the scale of hand specimen yet the mechanism of deformation is (micro)fracturing andor friction sliding

bull Cataclasis is mesoscopic ductile behavior (韌性變形行為) yet the process by which it occurs is microscopic brittle fracturing (脆性的顆粒破碎作用)and frictional sliding

Cataclastic Flow (碎屑流動)

bull 破碎岩(cataclastic rock)一旦形成之後這些破碎顆粒會因為斷層的再度活動而以破碎作用顆粒間的摩擦滑動剛體旋轉的方式流動這種流動稱為碎屑流動破碎流動很像未固結沈積物的顆粒流動(granular flow)但差別在於

1 顆粒流動時大部分的的顆粒並未進一步地破碎而破碎流動則是大部分的顆粒會進一步地變得更為破碎

2 顆粒流動只有在顆粒邊界的強度小於顆粒本身的強度內聚力很小而且圍壓很小時才會產生而破碎流動則是在軸差應力超過岩石顆粒的強度時才能產生

Cataclasite (破碎岩)

bull Thin section (crossed polars quartz plate) of cataclasite with angular broken fragments of quartz and feldspar in a very fine-grained matrix of phyllosilicate minerals and quartz powder Nelsprint E Transvaal S Africa RampH photo

Cataclastic rock (破碎岩)

(照片寬度為02 mm) Courtesy of Prof Yang Chao-Nan

Crystal Defects (晶體缺陷)

bull Ductile behavior (韌性行為) of materials at elevated temperature by the motion of crystal defects

bull A crystal defect is an error in the crystal lattice there are three basic types(1) Point defects (點缺陷)(2) Line defects (線缺陷) or dislocations (差排)(3) Planar defects (面缺陷) or stack faults

Crystal Defects (晶體缺陷)bull The motion of defects give rise to permanent

strain without the material losing cohesion (ie without fracturing)

bull Point and line defects are most important for the deformation of rock

bull Planar defects which arise from errors in the internal layering of minerals play only a limited role in deformation

Point defects

(a) Vacancies (空缺)

(b) Substitution (替代雜質)

(c) Interstitials (間隙雜質)

(d) Vacancy migration (空缺遷移)Diffusion

Diffusion (擴散作用)

bull Vacancies can migrate by exchange with atoms in neighboring sites

bull When an atoms moves into a vacant site you can equally say that the vacancy moved

Line Defects or DislocationsDislocation line The boundary between the unslippedand sipped portion of the crystal

Edge dislocation (刃差排)

Screw dislocation(螺旋差排)

Edge dislocation (刃差排)bull Occurs where there is an extra half-plane (多半面) of atoms

in the crystal latticebull Symbol for edge location is or depending on whether

the location of the extra half-plane is above or below the associated gliding plane of the crystal

Screw dislocation (螺旋差排)

bull Atoms are arranged in a corkscrew-like fashion the axis of the screw marks the dislocation line (line CD)

Burgers vector (Burgers 向量)

bull In a deformed crystal an atom-by-atom circuit around the dislocation fails to close by one or more atomic distances while a similar circuit around atoms in a perfect crystal would be complete The arrow connecting the two ends of the incomplete circuit is called Burgers vector

bull The length of Burgers vector in most minerals is on the order of nanometers

Determination of the Burgers vector (伯格向量)

(1) b perpendicular to l(2) Burgers cricuit

remain in the same plane

柏格環路

Determination of the Burgers vector (伯格向量)

(1) b and l are parallel(2) Potential slip plane(3) Glide plane

crystallogrphic plane

柏格環路 Table 91

Mixed dislocations (混合差排)

bull Edge and screw dislocations are only end-member geometries (perfect dislocation) dislocations that consists of part edge and part screw components are called mixed dislocation

Dislocation in olivine

Stress field around an edge dislocation

Wood-split analogy

Shear stress

Interactions between neighboring edge dislocation

(b) Like dislocation on widely separated glide planes may attract or repel depending on the angle between the lines joining the dislocation

(c) Unlike dislocation on the same or nearby glide planes attract

(a) Like dislocation on the same or nearby glide planes repel

Crystal Plasticity (晶體的塑性流動)

bull Dislocation are able to migrate through the crystal lattice if the activation energy (活化能) for movement is achieved

bull Distortion of crystal lattice around the dislocation is one source of driving energy as the system tries to achieve a lower internal strain energy

bull Applying a differential stress is another driving mechanism for dislocation motion

Crystal Plasticity (晶體的塑性流動)

bull Associated distortion of solid phases is called crystal plasticity

bull Dislocation movement may occur by glide and a combination of glide and climb (creep)depending mainly on temperature

bull Twinning (双晶 crystal-plastic behavior)occurs at low temperature in some minerals

Crystal Plasticity (晶體的塑性流動)

(1) Dislocation Glide (差排滑動)(2) Cross-slip and climb (側向滑動與爬升) (3) Mechanical Twinning (機械性的雙晶作用)

Dislocation glide (差排滑動)

Dislocation glide(差排滑動)

bull At low temperature dislocations are restricted to glide planes (or slip planes) The glide plane of a dislocation is the plane that contains the Burger vector (b) and the dislocation line (差排線 l) Each edge dislocation has one slip plane because b and l are perpendicular

bull A screw dislocation has many potential slip planes because b and l are parallel

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 3: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Three fundamental mechanisms

(1) Cataclastic flow (破裂與碎屑流)

(2) Diffusional mass transfer (物質擴散性轉移)

(3) Crystal plasticity (晶體塑性流動)

Which process dominate at a given time in a rockrsquos deformation history

bull Temperature (溫度)bull Stress (應力) bull Strain rate (應變速度) bull Grain size (顆粒尺寸) bull Composition (成分) bull Fluid content (流體含量)

Homologous temperature (溫度指標)

bull Homologous temperature A dimensionless parameter defined as the absolute temperature divided by the absolute melting temperature of the material (Th=TTm temperature in K)

bull Low-temperature condition 0 lt Th lt 03bull Medium -temperature condition 03 lt Th lt 07bull High-temperature condition 07 lt Th lt 1

Cataclastic flow (碎屑流動) Bean bag experiment

Such a process where a mesoscopic body (the bean bag) changes shape without breaking into separate pieces but the constituents (the beans) fracture into smaller pieces andor pass one another

Cataclastic Flow (碎屑流動)bull In rocks the tiny structures are called microcracks

and the pieces of move past one another by the process of frictional sliding (克服摩擦力的滑動)

bull During cataclastic flow a rock deforms without obvious strain localization (應變集中) on the scale of hand specimen yet the mechanism of deformation is (micro)fracturing andor friction sliding

bull Cataclasis is mesoscopic ductile behavior (韌性變形行為) yet the process by which it occurs is microscopic brittle fracturing (脆性的顆粒破碎作用)and frictional sliding

Cataclastic Flow (碎屑流動)

bull 破碎岩(cataclastic rock)一旦形成之後這些破碎顆粒會因為斷層的再度活動而以破碎作用顆粒間的摩擦滑動剛體旋轉的方式流動這種流動稱為碎屑流動破碎流動很像未固結沈積物的顆粒流動(granular flow)但差別在於

1 顆粒流動時大部分的的顆粒並未進一步地破碎而破碎流動則是大部分的顆粒會進一步地變得更為破碎

2 顆粒流動只有在顆粒邊界的強度小於顆粒本身的強度內聚力很小而且圍壓很小時才會產生而破碎流動則是在軸差應力超過岩石顆粒的強度時才能產生

Cataclasite (破碎岩)

bull Thin section (crossed polars quartz plate) of cataclasite with angular broken fragments of quartz and feldspar in a very fine-grained matrix of phyllosilicate minerals and quartz powder Nelsprint E Transvaal S Africa RampH photo

Cataclastic rock (破碎岩)

(照片寬度為02 mm) Courtesy of Prof Yang Chao-Nan

Crystal Defects (晶體缺陷)

bull Ductile behavior (韌性行為) of materials at elevated temperature by the motion of crystal defects

bull A crystal defect is an error in the crystal lattice there are three basic types(1) Point defects (點缺陷)(2) Line defects (線缺陷) or dislocations (差排)(3) Planar defects (面缺陷) or stack faults

Crystal Defects (晶體缺陷)bull The motion of defects give rise to permanent

strain without the material losing cohesion (ie without fracturing)

bull Point and line defects are most important for the deformation of rock

bull Planar defects which arise from errors in the internal layering of minerals play only a limited role in deformation

Point defects

(a) Vacancies (空缺)

(b) Substitution (替代雜質)

(c) Interstitials (間隙雜質)

(d) Vacancy migration (空缺遷移)Diffusion

Diffusion (擴散作用)

bull Vacancies can migrate by exchange with atoms in neighboring sites

bull When an atoms moves into a vacant site you can equally say that the vacancy moved

Line Defects or DislocationsDislocation line The boundary between the unslippedand sipped portion of the crystal

Edge dislocation (刃差排)

Screw dislocation(螺旋差排)

Edge dislocation (刃差排)bull Occurs where there is an extra half-plane (多半面) of atoms

in the crystal latticebull Symbol for edge location is or depending on whether

the location of the extra half-plane is above or below the associated gliding plane of the crystal

Screw dislocation (螺旋差排)

bull Atoms are arranged in a corkscrew-like fashion the axis of the screw marks the dislocation line (line CD)

Burgers vector (Burgers 向量)

bull In a deformed crystal an atom-by-atom circuit around the dislocation fails to close by one or more atomic distances while a similar circuit around atoms in a perfect crystal would be complete The arrow connecting the two ends of the incomplete circuit is called Burgers vector

bull The length of Burgers vector in most minerals is on the order of nanometers

Determination of the Burgers vector (伯格向量)

(1) b perpendicular to l(2) Burgers cricuit

remain in the same plane

柏格環路

Determination of the Burgers vector (伯格向量)

(1) b and l are parallel(2) Potential slip plane(3) Glide plane

crystallogrphic plane

柏格環路 Table 91

Mixed dislocations (混合差排)

bull Edge and screw dislocations are only end-member geometries (perfect dislocation) dislocations that consists of part edge and part screw components are called mixed dislocation

Dislocation in olivine

Stress field around an edge dislocation

Wood-split analogy

Shear stress

Interactions between neighboring edge dislocation

(b) Like dislocation on widely separated glide planes may attract or repel depending on the angle between the lines joining the dislocation

(c) Unlike dislocation on the same or nearby glide planes attract

(a) Like dislocation on the same or nearby glide planes repel

Crystal Plasticity (晶體的塑性流動)

bull Dislocation are able to migrate through the crystal lattice if the activation energy (活化能) for movement is achieved

bull Distortion of crystal lattice around the dislocation is one source of driving energy as the system tries to achieve a lower internal strain energy

bull Applying a differential stress is another driving mechanism for dislocation motion

Crystal Plasticity (晶體的塑性流動)

bull Associated distortion of solid phases is called crystal plasticity

bull Dislocation movement may occur by glide and a combination of glide and climb (creep)depending mainly on temperature

bull Twinning (双晶 crystal-plastic behavior)occurs at low temperature in some minerals

Crystal Plasticity (晶體的塑性流動)

(1) Dislocation Glide (差排滑動)(2) Cross-slip and climb (側向滑動與爬升) (3) Mechanical Twinning (機械性的雙晶作用)

Dislocation glide (差排滑動)

Dislocation glide(差排滑動)

bull At low temperature dislocations are restricted to glide planes (or slip planes) The glide plane of a dislocation is the plane that contains the Burger vector (b) and the dislocation line (差排線 l) Each edge dislocation has one slip plane because b and l are perpendicular

bull A screw dislocation has many potential slip planes because b and l are parallel

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 4: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Which process dominate at a given time in a rockrsquos deformation history

bull Temperature (溫度)bull Stress (應力) bull Strain rate (應變速度) bull Grain size (顆粒尺寸) bull Composition (成分) bull Fluid content (流體含量)

Homologous temperature (溫度指標)

bull Homologous temperature A dimensionless parameter defined as the absolute temperature divided by the absolute melting temperature of the material (Th=TTm temperature in K)

bull Low-temperature condition 0 lt Th lt 03bull Medium -temperature condition 03 lt Th lt 07bull High-temperature condition 07 lt Th lt 1

Cataclastic flow (碎屑流動) Bean bag experiment

Such a process where a mesoscopic body (the bean bag) changes shape without breaking into separate pieces but the constituents (the beans) fracture into smaller pieces andor pass one another

Cataclastic Flow (碎屑流動)bull In rocks the tiny structures are called microcracks

and the pieces of move past one another by the process of frictional sliding (克服摩擦力的滑動)

bull During cataclastic flow a rock deforms without obvious strain localization (應變集中) on the scale of hand specimen yet the mechanism of deformation is (micro)fracturing andor friction sliding

bull Cataclasis is mesoscopic ductile behavior (韌性變形行為) yet the process by which it occurs is microscopic brittle fracturing (脆性的顆粒破碎作用)and frictional sliding

Cataclastic Flow (碎屑流動)

bull 破碎岩(cataclastic rock)一旦形成之後這些破碎顆粒會因為斷層的再度活動而以破碎作用顆粒間的摩擦滑動剛體旋轉的方式流動這種流動稱為碎屑流動破碎流動很像未固結沈積物的顆粒流動(granular flow)但差別在於

1 顆粒流動時大部分的的顆粒並未進一步地破碎而破碎流動則是大部分的顆粒會進一步地變得更為破碎

2 顆粒流動只有在顆粒邊界的強度小於顆粒本身的強度內聚力很小而且圍壓很小時才會產生而破碎流動則是在軸差應力超過岩石顆粒的強度時才能產生

Cataclasite (破碎岩)

bull Thin section (crossed polars quartz plate) of cataclasite with angular broken fragments of quartz and feldspar in a very fine-grained matrix of phyllosilicate minerals and quartz powder Nelsprint E Transvaal S Africa RampH photo

Cataclastic rock (破碎岩)

(照片寬度為02 mm) Courtesy of Prof Yang Chao-Nan

Crystal Defects (晶體缺陷)

bull Ductile behavior (韌性行為) of materials at elevated temperature by the motion of crystal defects

bull A crystal defect is an error in the crystal lattice there are three basic types(1) Point defects (點缺陷)(2) Line defects (線缺陷) or dislocations (差排)(3) Planar defects (面缺陷) or stack faults

Crystal Defects (晶體缺陷)bull The motion of defects give rise to permanent

strain without the material losing cohesion (ie without fracturing)

bull Point and line defects are most important for the deformation of rock

bull Planar defects which arise from errors in the internal layering of minerals play only a limited role in deformation

Point defects

(a) Vacancies (空缺)

(b) Substitution (替代雜質)

(c) Interstitials (間隙雜質)

(d) Vacancy migration (空缺遷移)Diffusion

Diffusion (擴散作用)

bull Vacancies can migrate by exchange with atoms in neighboring sites

bull When an atoms moves into a vacant site you can equally say that the vacancy moved

Line Defects or DislocationsDislocation line The boundary between the unslippedand sipped portion of the crystal

Edge dislocation (刃差排)

Screw dislocation(螺旋差排)

Edge dislocation (刃差排)bull Occurs where there is an extra half-plane (多半面) of atoms

in the crystal latticebull Symbol for edge location is or depending on whether

the location of the extra half-plane is above or below the associated gliding plane of the crystal

Screw dislocation (螺旋差排)

bull Atoms are arranged in a corkscrew-like fashion the axis of the screw marks the dislocation line (line CD)

Burgers vector (Burgers 向量)

bull In a deformed crystal an atom-by-atom circuit around the dislocation fails to close by one or more atomic distances while a similar circuit around atoms in a perfect crystal would be complete The arrow connecting the two ends of the incomplete circuit is called Burgers vector

bull The length of Burgers vector in most minerals is on the order of nanometers

Determination of the Burgers vector (伯格向量)

(1) b perpendicular to l(2) Burgers cricuit

remain in the same plane

柏格環路

Determination of the Burgers vector (伯格向量)

(1) b and l are parallel(2) Potential slip plane(3) Glide plane

crystallogrphic plane

柏格環路 Table 91

Mixed dislocations (混合差排)

bull Edge and screw dislocations are only end-member geometries (perfect dislocation) dislocations that consists of part edge and part screw components are called mixed dislocation

Dislocation in olivine

Stress field around an edge dislocation

Wood-split analogy

Shear stress

Interactions between neighboring edge dislocation

(b) Like dislocation on widely separated glide planes may attract or repel depending on the angle between the lines joining the dislocation

(c) Unlike dislocation on the same or nearby glide planes attract

(a) Like dislocation on the same or nearby glide planes repel

Crystal Plasticity (晶體的塑性流動)

bull Dislocation are able to migrate through the crystal lattice if the activation energy (活化能) for movement is achieved

bull Distortion of crystal lattice around the dislocation is one source of driving energy as the system tries to achieve a lower internal strain energy

bull Applying a differential stress is another driving mechanism for dislocation motion

Crystal Plasticity (晶體的塑性流動)

bull Associated distortion of solid phases is called crystal plasticity

bull Dislocation movement may occur by glide and a combination of glide and climb (creep)depending mainly on temperature

bull Twinning (双晶 crystal-plastic behavior)occurs at low temperature in some minerals

Crystal Plasticity (晶體的塑性流動)

(1) Dislocation Glide (差排滑動)(2) Cross-slip and climb (側向滑動與爬升) (3) Mechanical Twinning (機械性的雙晶作用)

Dislocation glide (差排滑動)

Dislocation glide(差排滑動)

bull At low temperature dislocations are restricted to glide planes (or slip planes) The glide plane of a dislocation is the plane that contains the Burger vector (b) and the dislocation line (差排線 l) Each edge dislocation has one slip plane because b and l are perpendicular

bull A screw dislocation has many potential slip planes because b and l are parallel

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 5: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Homologous temperature (溫度指標)

bull Homologous temperature A dimensionless parameter defined as the absolute temperature divided by the absolute melting temperature of the material (Th=TTm temperature in K)

bull Low-temperature condition 0 lt Th lt 03bull Medium -temperature condition 03 lt Th lt 07bull High-temperature condition 07 lt Th lt 1

Cataclastic flow (碎屑流動) Bean bag experiment

Such a process where a mesoscopic body (the bean bag) changes shape without breaking into separate pieces but the constituents (the beans) fracture into smaller pieces andor pass one another

Cataclastic Flow (碎屑流動)bull In rocks the tiny structures are called microcracks

and the pieces of move past one another by the process of frictional sliding (克服摩擦力的滑動)

bull During cataclastic flow a rock deforms without obvious strain localization (應變集中) on the scale of hand specimen yet the mechanism of deformation is (micro)fracturing andor friction sliding

bull Cataclasis is mesoscopic ductile behavior (韌性變形行為) yet the process by which it occurs is microscopic brittle fracturing (脆性的顆粒破碎作用)and frictional sliding

Cataclastic Flow (碎屑流動)

bull 破碎岩(cataclastic rock)一旦形成之後這些破碎顆粒會因為斷層的再度活動而以破碎作用顆粒間的摩擦滑動剛體旋轉的方式流動這種流動稱為碎屑流動破碎流動很像未固結沈積物的顆粒流動(granular flow)但差別在於

1 顆粒流動時大部分的的顆粒並未進一步地破碎而破碎流動則是大部分的顆粒會進一步地變得更為破碎

2 顆粒流動只有在顆粒邊界的強度小於顆粒本身的強度內聚力很小而且圍壓很小時才會產生而破碎流動則是在軸差應力超過岩石顆粒的強度時才能產生

Cataclasite (破碎岩)

bull Thin section (crossed polars quartz plate) of cataclasite with angular broken fragments of quartz and feldspar in a very fine-grained matrix of phyllosilicate minerals and quartz powder Nelsprint E Transvaal S Africa RampH photo

Cataclastic rock (破碎岩)

(照片寬度為02 mm) Courtesy of Prof Yang Chao-Nan

Crystal Defects (晶體缺陷)

bull Ductile behavior (韌性行為) of materials at elevated temperature by the motion of crystal defects

bull A crystal defect is an error in the crystal lattice there are three basic types(1) Point defects (點缺陷)(2) Line defects (線缺陷) or dislocations (差排)(3) Planar defects (面缺陷) or stack faults

Crystal Defects (晶體缺陷)bull The motion of defects give rise to permanent

strain without the material losing cohesion (ie without fracturing)

bull Point and line defects are most important for the deformation of rock

bull Planar defects which arise from errors in the internal layering of minerals play only a limited role in deformation

Point defects

(a) Vacancies (空缺)

(b) Substitution (替代雜質)

(c) Interstitials (間隙雜質)

(d) Vacancy migration (空缺遷移)Diffusion

Diffusion (擴散作用)

bull Vacancies can migrate by exchange with atoms in neighboring sites

bull When an atoms moves into a vacant site you can equally say that the vacancy moved

Line Defects or DislocationsDislocation line The boundary between the unslippedand sipped portion of the crystal

Edge dislocation (刃差排)

Screw dislocation(螺旋差排)

Edge dislocation (刃差排)bull Occurs where there is an extra half-plane (多半面) of atoms

in the crystal latticebull Symbol for edge location is or depending on whether

the location of the extra half-plane is above or below the associated gliding plane of the crystal

Screw dislocation (螺旋差排)

bull Atoms are arranged in a corkscrew-like fashion the axis of the screw marks the dislocation line (line CD)

Burgers vector (Burgers 向量)

bull In a deformed crystal an atom-by-atom circuit around the dislocation fails to close by one or more atomic distances while a similar circuit around atoms in a perfect crystal would be complete The arrow connecting the two ends of the incomplete circuit is called Burgers vector

bull The length of Burgers vector in most minerals is on the order of nanometers

Determination of the Burgers vector (伯格向量)

(1) b perpendicular to l(2) Burgers cricuit

remain in the same plane

柏格環路

Determination of the Burgers vector (伯格向量)

(1) b and l are parallel(2) Potential slip plane(3) Glide plane

crystallogrphic plane

柏格環路 Table 91

Mixed dislocations (混合差排)

bull Edge and screw dislocations are only end-member geometries (perfect dislocation) dislocations that consists of part edge and part screw components are called mixed dislocation

Dislocation in olivine

Stress field around an edge dislocation

Wood-split analogy

Shear stress

Interactions between neighboring edge dislocation

(b) Like dislocation on widely separated glide planes may attract or repel depending on the angle between the lines joining the dislocation

(c) Unlike dislocation on the same or nearby glide planes attract

(a) Like dislocation on the same or nearby glide planes repel

Crystal Plasticity (晶體的塑性流動)

bull Dislocation are able to migrate through the crystal lattice if the activation energy (活化能) for movement is achieved

bull Distortion of crystal lattice around the dislocation is one source of driving energy as the system tries to achieve a lower internal strain energy

bull Applying a differential stress is another driving mechanism for dislocation motion

Crystal Plasticity (晶體的塑性流動)

bull Associated distortion of solid phases is called crystal plasticity

bull Dislocation movement may occur by glide and a combination of glide and climb (creep)depending mainly on temperature

bull Twinning (双晶 crystal-plastic behavior)occurs at low temperature in some minerals

Crystal Plasticity (晶體的塑性流動)

(1) Dislocation Glide (差排滑動)(2) Cross-slip and climb (側向滑動與爬升) (3) Mechanical Twinning (機械性的雙晶作用)

Dislocation glide (差排滑動)

Dislocation glide(差排滑動)

bull At low temperature dislocations are restricted to glide planes (or slip planes) The glide plane of a dislocation is the plane that contains the Burger vector (b) and the dislocation line (差排線 l) Each edge dislocation has one slip plane because b and l are perpendicular

bull A screw dislocation has many potential slip planes because b and l are parallel

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 6: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Cataclastic flow (碎屑流動) Bean bag experiment

Such a process where a mesoscopic body (the bean bag) changes shape without breaking into separate pieces but the constituents (the beans) fracture into smaller pieces andor pass one another

Cataclastic Flow (碎屑流動)bull In rocks the tiny structures are called microcracks

and the pieces of move past one another by the process of frictional sliding (克服摩擦力的滑動)

bull During cataclastic flow a rock deforms without obvious strain localization (應變集中) on the scale of hand specimen yet the mechanism of deformation is (micro)fracturing andor friction sliding

bull Cataclasis is mesoscopic ductile behavior (韌性變形行為) yet the process by which it occurs is microscopic brittle fracturing (脆性的顆粒破碎作用)and frictional sliding

Cataclastic Flow (碎屑流動)

bull 破碎岩(cataclastic rock)一旦形成之後這些破碎顆粒會因為斷層的再度活動而以破碎作用顆粒間的摩擦滑動剛體旋轉的方式流動這種流動稱為碎屑流動破碎流動很像未固結沈積物的顆粒流動(granular flow)但差別在於

1 顆粒流動時大部分的的顆粒並未進一步地破碎而破碎流動則是大部分的顆粒會進一步地變得更為破碎

2 顆粒流動只有在顆粒邊界的強度小於顆粒本身的強度內聚力很小而且圍壓很小時才會產生而破碎流動則是在軸差應力超過岩石顆粒的強度時才能產生

Cataclasite (破碎岩)

bull Thin section (crossed polars quartz plate) of cataclasite with angular broken fragments of quartz and feldspar in a very fine-grained matrix of phyllosilicate minerals and quartz powder Nelsprint E Transvaal S Africa RampH photo

Cataclastic rock (破碎岩)

(照片寬度為02 mm) Courtesy of Prof Yang Chao-Nan

Crystal Defects (晶體缺陷)

bull Ductile behavior (韌性行為) of materials at elevated temperature by the motion of crystal defects

bull A crystal defect is an error in the crystal lattice there are three basic types(1) Point defects (點缺陷)(2) Line defects (線缺陷) or dislocations (差排)(3) Planar defects (面缺陷) or stack faults

Crystal Defects (晶體缺陷)bull The motion of defects give rise to permanent

strain without the material losing cohesion (ie without fracturing)

bull Point and line defects are most important for the deformation of rock

bull Planar defects which arise from errors in the internal layering of minerals play only a limited role in deformation

Point defects

(a) Vacancies (空缺)

(b) Substitution (替代雜質)

(c) Interstitials (間隙雜質)

(d) Vacancy migration (空缺遷移)Diffusion

Diffusion (擴散作用)

bull Vacancies can migrate by exchange with atoms in neighboring sites

bull When an atoms moves into a vacant site you can equally say that the vacancy moved

Line Defects or DislocationsDislocation line The boundary between the unslippedand sipped portion of the crystal

Edge dislocation (刃差排)

Screw dislocation(螺旋差排)

Edge dislocation (刃差排)bull Occurs where there is an extra half-plane (多半面) of atoms

in the crystal latticebull Symbol for edge location is or depending on whether

the location of the extra half-plane is above or below the associated gliding plane of the crystal

Screw dislocation (螺旋差排)

bull Atoms are arranged in a corkscrew-like fashion the axis of the screw marks the dislocation line (line CD)

Burgers vector (Burgers 向量)

bull In a deformed crystal an atom-by-atom circuit around the dislocation fails to close by one or more atomic distances while a similar circuit around atoms in a perfect crystal would be complete The arrow connecting the two ends of the incomplete circuit is called Burgers vector

bull The length of Burgers vector in most minerals is on the order of nanometers

Determination of the Burgers vector (伯格向量)

(1) b perpendicular to l(2) Burgers cricuit

remain in the same plane

柏格環路

Determination of the Burgers vector (伯格向量)

(1) b and l are parallel(2) Potential slip plane(3) Glide plane

crystallogrphic plane

柏格環路 Table 91

Mixed dislocations (混合差排)

bull Edge and screw dislocations are only end-member geometries (perfect dislocation) dislocations that consists of part edge and part screw components are called mixed dislocation

Dislocation in olivine

Stress field around an edge dislocation

Wood-split analogy

Shear stress

Interactions between neighboring edge dislocation

(b) Like dislocation on widely separated glide planes may attract or repel depending on the angle between the lines joining the dislocation

(c) Unlike dislocation on the same or nearby glide planes attract

(a) Like dislocation on the same or nearby glide planes repel

Crystal Plasticity (晶體的塑性流動)

bull Dislocation are able to migrate through the crystal lattice if the activation energy (活化能) for movement is achieved

bull Distortion of crystal lattice around the dislocation is one source of driving energy as the system tries to achieve a lower internal strain energy

bull Applying a differential stress is another driving mechanism for dislocation motion

Crystal Plasticity (晶體的塑性流動)

bull Associated distortion of solid phases is called crystal plasticity

bull Dislocation movement may occur by glide and a combination of glide and climb (creep)depending mainly on temperature

bull Twinning (双晶 crystal-plastic behavior)occurs at low temperature in some minerals

Crystal Plasticity (晶體的塑性流動)

(1) Dislocation Glide (差排滑動)(2) Cross-slip and climb (側向滑動與爬升) (3) Mechanical Twinning (機械性的雙晶作用)

Dislocation glide (差排滑動)

Dislocation glide(差排滑動)

bull At low temperature dislocations are restricted to glide planes (or slip planes) The glide plane of a dislocation is the plane that contains the Burger vector (b) and the dislocation line (差排線 l) Each edge dislocation has one slip plane because b and l are perpendicular

bull A screw dislocation has many potential slip planes because b and l are parallel

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 7: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Cataclastic Flow (碎屑流動)bull In rocks the tiny structures are called microcracks

and the pieces of move past one another by the process of frictional sliding (克服摩擦力的滑動)

bull During cataclastic flow a rock deforms without obvious strain localization (應變集中) on the scale of hand specimen yet the mechanism of deformation is (micro)fracturing andor friction sliding

bull Cataclasis is mesoscopic ductile behavior (韌性變形行為) yet the process by which it occurs is microscopic brittle fracturing (脆性的顆粒破碎作用)and frictional sliding

Cataclastic Flow (碎屑流動)

bull 破碎岩(cataclastic rock)一旦形成之後這些破碎顆粒會因為斷層的再度活動而以破碎作用顆粒間的摩擦滑動剛體旋轉的方式流動這種流動稱為碎屑流動破碎流動很像未固結沈積物的顆粒流動(granular flow)但差別在於

1 顆粒流動時大部分的的顆粒並未進一步地破碎而破碎流動則是大部分的顆粒會進一步地變得更為破碎

2 顆粒流動只有在顆粒邊界的強度小於顆粒本身的強度內聚力很小而且圍壓很小時才會產生而破碎流動則是在軸差應力超過岩石顆粒的強度時才能產生

Cataclasite (破碎岩)

bull Thin section (crossed polars quartz plate) of cataclasite with angular broken fragments of quartz and feldspar in a very fine-grained matrix of phyllosilicate minerals and quartz powder Nelsprint E Transvaal S Africa RampH photo

Cataclastic rock (破碎岩)

(照片寬度為02 mm) Courtesy of Prof Yang Chao-Nan

Crystal Defects (晶體缺陷)

bull Ductile behavior (韌性行為) of materials at elevated temperature by the motion of crystal defects

bull A crystal defect is an error in the crystal lattice there are three basic types(1) Point defects (點缺陷)(2) Line defects (線缺陷) or dislocations (差排)(3) Planar defects (面缺陷) or stack faults

Crystal Defects (晶體缺陷)bull The motion of defects give rise to permanent

strain without the material losing cohesion (ie without fracturing)

bull Point and line defects are most important for the deformation of rock

bull Planar defects which arise from errors in the internal layering of minerals play only a limited role in deformation

Point defects

(a) Vacancies (空缺)

(b) Substitution (替代雜質)

(c) Interstitials (間隙雜質)

(d) Vacancy migration (空缺遷移)Diffusion

Diffusion (擴散作用)

bull Vacancies can migrate by exchange with atoms in neighboring sites

bull When an atoms moves into a vacant site you can equally say that the vacancy moved

Line Defects or DislocationsDislocation line The boundary between the unslippedand sipped portion of the crystal

Edge dislocation (刃差排)

Screw dislocation(螺旋差排)

Edge dislocation (刃差排)bull Occurs where there is an extra half-plane (多半面) of atoms

in the crystal latticebull Symbol for edge location is or depending on whether

the location of the extra half-plane is above or below the associated gliding plane of the crystal

Screw dislocation (螺旋差排)

bull Atoms are arranged in a corkscrew-like fashion the axis of the screw marks the dislocation line (line CD)

Burgers vector (Burgers 向量)

bull In a deformed crystal an atom-by-atom circuit around the dislocation fails to close by one or more atomic distances while a similar circuit around atoms in a perfect crystal would be complete The arrow connecting the two ends of the incomplete circuit is called Burgers vector

bull The length of Burgers vector in most minerals is on the order of nanometers

Determination of the Burgers vector (伯格向量)

(1) b perpendicular to l(2) Burgers cricuit

remain in the same plane

柏格環路

Determination of the Burgers vector (伯格向量)

(1) b and l are parallel(2) Potential slip plane(3) Glide plane

crystallogrphic plane

柏格環路 Table 91

Mixed dislocations (混合差排)

bull Edge and screw dislocations are only end-member geometries (perfect dislocation) dislocations that consists of part edge and part screw components are called mixed dislocation

Dislocation in olivine

Stress field around an edge dislocation

Wood-split analogy

Shear stress

Interactions between neighboring edge dislocation

(b) Like dislocation on widely separated glide planes may attract or repel depending on the angle between the lines joining the dislocation

(c) Unlike dislocation on the same or nearby glide planes attract

(a) Like dislocation on the same or nearby glide planes repel

Crystal Plasticity (晶體的塑性流動)

bull Dislocation are able to migrate through the crystal lattice if the activation energy (活化能) for movement is achieved

bull Distortion of crystal lattice around the dislocation is one source of driving energy as the system tries to achieve a lower internal strain energy

bull Applying a differential stress is another driving mechanism for dislocation motion

Crystal Plasticity (晶體的塑性流動)

bull Associated distortion of solid phases is called crystal plasticity

bull Dislocation movement may occur by glide and a combination of glide and climb (creep)depending mainly on temperature

bull Twinning (双晶 crystal-plastic behavior)occurs at low temperature in some minerals

Crystal Plasticity (晶體的塑性流動)

(1) Dislocation Glide (差排滑動)(2) Cross-slip and climb (側向滑動與爬升) (3) Mechanical Twinning (機械性的雙晶作用)

Dislocation glide (差排滑動)

Dislocation glide(差排滑動)

bull At low temperature dislocations are restricted to glide planes (or slip planes) The glide plane of a dislocation is the plane that contains the Burger vector (b) and the dislocation line (差排線 l) Each edge dislocation has one slip plane because b and l are perpendicular

bull A screw dislocation has many potential slip planes because b and l are parallel

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 8: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Cataclastic Flow (碎屑流動)

bull 破碎岩(cataclastic rock)一旦形成之後這些破碎顆粒會因為斷層的再度活動而以破碎作用顆粒間的摩擦滑動剛體旋轉的方式流動這種流動稱為碎屑流動破碎流動很像未固結沈積物的顆粒流動(granular flow)但差別在於

1 顆粒流動時大部分的的顆粒並未進一步地破碎而破碎流動則是大部分的顆粒會進一步地變得更為破碎

2 顆粒流動只有在顆粒邊界的強度小於顆粒本身的強度內聚力很小而且圍壓很小時才會產生而破碎流動則是在軸差應力超過岩石顆粒的強度時才能產生

Cataclasite (破碎岩)

bull Thin section (crossed polars quartz plate) of cataclasite with angular broken fragments of quartz and feldspar in a very fine-grained matrix of phyllosilicate minerals and quartz powder Nelsprint E Transvaal S Africa RampH photo

Cataclastic rock (破碎岩)

(照片寬度為02 mm) Courtesy of Prof Yang Chao-Nan

Crystal Defects (晶體缺陷)

bull Ductile behavior (韌性行為) of materials at elevated temperature by the motion of crystal defects

bull A crystal defect is an error in the crystal lattice there are three basic types(1) Point defects (點缺陷)(2) Line defects (線缺陷) or dislocations (差排)(3) Planar defects (面缺陷) or stack faults

Crystal Defects (晶體缺陷)bull The motion of defects give rise to permanent

strain without the material losing cohesion (ie without fracturing)

bull Point and line defects are most important for the deformation of rock

bull Planar defects which arise from errors in the internal layering of minerals play only a limited role in deformation

Point defects

(a) Vacancies (空缺)

(b) Substitution (替代雜質)

(c) Interstitials (間隙雜質)

(d) Vacancy migration (空缺遷移)Diffusion

Diffusion (擴散作用)

bull Vacancies can migrate by exchange with atoms in neighboring sites

bull When an atoms moves into a vacant site you can equally say that the vacancy moved

Line Defects or DislocationsDislocation line The boundary between the unslippedand sipped portion of the crystal

Edge dislocation (刃差排)

Screw dislocation(螺旋差排)

Edge dislocation (刃差排)bull Occurs where there is an extra half-plane (多半面) of atoms

in the crystal latticebull Symbol for edge location is or depending on whether

the location of the extra half-plane is above or below the associated gliding plane of the crystal

Screw dislocation (螺旋差排)

bull Atoms are arranged in a corkscrew-like fashion the axis of the screw marks the dislocation line (line CD)

Burgers vector (Burgers 向量)

bull In a deformed crystal an atom-by-atom circuit around the dislocation fails to close by one or more atomic distances while a similar circuit around atoms in a perfect crystal would be complete The arrow connecting the two ends of the incomplete circuit is called Burgers vector

bull The length of Burgers vector in most minerals is on the order of nanometers

Determination of the Burgers vector (伯格向量)

(1) b perpendicular to l(2) Burgers cricuit

remain in the same plane

柏格環路

Determination of the Burgers vector (伯格向量)

(1) b and l are parallel(2) Potential slip plane(3) Glide plane

crystallogrphic plane

柏格環路 Table 91

Mixed dislocations (混合差排)

bull Edge and screw dislocations are only end-member geometries (perfect dislocation) dislocations that consists of part edge and part screw components are called mixed dislocation

Dislocation in olivine

Stress field around an edge dislocation

Wood-split analogy

Shear stress

Interactions between neighboring edge dislocation

(b) Like dislocation on widely separated glide planes may attract or repel depending on the angle between the lines joining the dislocation

(c) Unlike dislocation on the same or nearby glide planes attract

(a) Like dislocation on the same or nearby glide planes repel

Crystal Plasticity (晶體的塑性流動)

bull Dislocation are able to migrate through the crystal lattice if the activation energy (活化能) for movement is achieved

bull Distortion of crystal lattice around the dislocation is one source of driving energy as the system tries to achieve a lower internal strain energy

bull Applying a differential stress is another driving mechanism for dislocation motion

Crystal Plasticity (晶體的塑性流動)

bull Associated distortion of solid phases is called crystal plasticity

bull Dislocation movement may occur by glide and a combination of glide and climb (creep)depending mainly on temperature

bull Twinning (双晶 crystal-plastic behavior)occurs at low temperature in some minerals

Crystal Plasticity (晶體的塑性流動)

(1) Dislocation Glide (差排滑動)(2) Cross-slip and climb (側向滑動與爬升) (3) Mechanical Twinning (機械性的雙晶作用)

Dislocation glide (差排滑動)

Dislocation glide(差排滑動)

bull At low temperature dislocations are restricted to glide planes (or slip planes) The glide plane of a dislocation is the plane that contains the Burger vector (b) and the dislocation line (差排線 l) Each edge dislocation has one slip plane because b and l are perpendicular

bull A screw dislocation has many potential slip planes because b and l are parallel

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 9: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Cataclasite (破碎岩)

bull Thin section (crossed polars quartz plate) of cataclasite with angular broken fragments of quartz and feldspar in a very fine-grained matrix of phyllosilicate minerals and quartz powder Nelsprint E Transvaal S Africa RampH photo

Cataclastic rock (破碎岩)

(照片寬度為02 mm) Courtesy of Prof Yang Chao-Nan

Crystal Defects (晶體缺陷)

bull Ductile behavior (韌性行為) of materials at elevated temperature by the motion of crystal defects

bull A crystal defect is an error in the crystal lattice there are three basic types(1) Point defects (點缺陷)(2) Line defects (線缺陷) or dislocations (差排)(3) Planar defects (面缺陷) or stack faults

Crystal Defects (晶體缺陷)bull The motion of defects give rise to permanent

strain without the material losing cohesion (ie without fracturing)

bull Point and line defects are most important for the deformation of rock

bull Planar defects which arise from errors in the internal layering of minerals play only a limited role in deformation

Point defects

(a) Vacancies (空缺)

(b) Substitution (替代雜質)

(c) Interstitials (間隙雜質)

(d) Vacancy migration (空缺遷移)Diffusion

Diffusion (擴散作用)

bull Vacancies can migrate by exchange with atoms in neighboring sites

bull When an atoms moves into a vacant site you can equally say that the vacancy moved

Line Defects or DislocationsDislocation line The boundary between the unslippedand sipped portion of the crystal

Edge dislocation (刃差排)

Screw dislocation(螺旋差排)

Edge dislocation (刃差排)bull Occurs where there is an extra half-plane (多半面) of atoms

in the crystal latticebull Symbol for edge location is or depending on whether

the location of the extra half-plane is above or below the associated gliding plane of the crystal

Screw dislocation (螺旋差排)

bull Atoms are arranged in a corkscrew-like fashion the axis of the screw marks the dislocation line (line CD)

Burgers vector (Burgers 向量)

bull In a deformed crystal an atom-by-atom circuit around the dislocation fails to close by one or more atomic distances while a similar circuit around atoms in a perfect crystal would be complete The arrow connecting the two ends of the incomplete circuit is called Burgers vector

bull The length of Burgers vector in most minerals is on the order of nanometers

Determination of the Burgers vector (伯格向量)

(1) b perpendicular to l(2) Burgers cricuit

remain in the same plane

柏格環路

Determination of the Burgers vector (伯格向量)

(1) b and l are parallel(2) Potential slip plane(3) Glide plane

crystallogrphic plane

柏格環路 Table 91

Mixed dislocations (混合差排)

bull Edge and screw dislocations are only end-member geometries (perfect dislocation) dislocations that consists of part edge and part screw components are called mixed dislocation

Dislocation in olivine

Stress field around an edge dislocation

Wood-split analogy

Shear stress

Interactions between neighboring edge dislocation

(b) Like dislocation on widely separated glide planes may attract or repel depending on the angle between the lines joining the dislocation

(c) Unlike dislocation on the same or nearby glide planes attract

(a) Like dislocation on the same or nearby glide planes repel

Crystal Plasticity (晶體的塑性流動)

bull Dislocation are able to migrate through the crystal lattice if the activation energy (活化能) for movement is achieved

bull Distortion of crystal lattice around the dislocation is one source of driving energy as the system tries to achieve a lower internal strain energy

bull Applying a differential stress is another driving mechanism for dislocation motion

Crystal Plasticity (晶體的塑性流動)

bull Associated distortion of solid phases is called crystal plasticity

bull Dislocation movement may occur by glide and a combination of glide and climb (creep)depending mainly on temperature

bull Twinning (双晶 crystal-plastic behavior)occurs at low temperature in some minerals

Crystal Plasticity (晶體的塑性流動)

(1) Dislocation Glide (差排滑動)(2) Cross-slip and climb (側向滑動與爬升) (3) Mechanical Twinning (機械性的雙晶作用)

Dislocation glide (差排滑動)

Dislocation glide(差排滑動)

bull At low temperature dislocations are restricted to glide planes (or slip planes) The glide plane of a dislocation is the plane that contains the Burger vector (b) and the dislocation line (差排線 l) Each edge dislocation has one slip plane because b and l are perpendicular

bull A screw dislocation has many potential slip planes because b and l are parallel

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 10: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Cataclastic rock (破碎岩)

(照片寬度為02 mm) Courtesy of Prof Yang Chao-Nan

Crystal Defects (晶體缺陷)

bull Ductile behavior (韌性行為) of materials at elevated temperature by the motion of crystal defects

bull A crystal defect is an error in the crystal lattice there are three basic types(1) Point defects (點缺陷)(2) Line defects (線缺陷) or dislocations (差排)(3) Planar defects (面缺陷) or stack faults

Crystal Defects (晶體缺陷)bull The motion of defects give rise to permanent

strain without the material losing cohesion (ie without fracturing)

bull Point and line defects are most important for the deformation of rock

bull Planar defects which arise from errors in the internal layering of minerals play only a limited role in deformation

Point defects

(a) Vacancies (空缺)

(b) Substitution (替代雜質)

(c) Interstitials (間隙雜質)

(d) Vacancy migration (空缺遷移)Diffusion

Diffusion (擴散作用)

bull Vacancies can migrate by exchange with atoms in neighboring sites

bull When an atoms moves into a vacant site you can equally say that the vacancy moved

Line Defects or DislocationsDislocation line The boundary between the unslippedand sipped portion of the crystal

Edge dislocation (刃差排)

Screw dislocation(螺旋差排)

Edge dislocation (刃差排)bull Occurs where there is an extra half-plane (多半面) of atoms

in the crystal latticebull Symbol for edge location is or depending on whether

the location of the extra half-plane is above or below the associated gliding plane of the crystal

Screw dislocation (螺旋差排)

bull Atoms are arranged in a corkscrew-like fashion the axis of the screw marks the dislocation line (line CD)

Burgers vector (Burgers 向量)

bull In a deformed crystal an atom-by-atom circuit around the dislocation fails to close by one or more atomic distances while a similar circuit around atoms in a perfect crystal would be complete The arrow connecting the two ends of the incomplete circuit is called Burgers vector

bull The length of Burgers vector in most minerals is on the order of nanometers

Determination of the Burgers vector (伯格向量)

(1) b perpendicular to l(2) Burgers cricuit

remain in the same plane

柏格環路

Determination of the Burgers vector (伯格向量)

(1) b and l are parallel(2) Potential slip plane(3) Glide plane

crystallogrphic plane

柏格環路 Table 91

Mixed dislocations (混合差排)

bull Edge and screw dislocations are only end-member geometries (perfect dislocation) dislocations that consists of part edge and part screw components are called mixed dislocation

Dislocation in olivine

Stress field around an edge dislocation

Wood-split analogy

Shear stress

Interactions between neighboring edge dislocation

(b) Like dislocation on widely separated glide planes may attract or repel depending on the angle between the lines joining the dislocation

(c) Unlike dislocation on the same or nearby glide planes attract

(a) Like dislocation on the same or nearby glide planes repel

Crystal Plasticity (晶體的塑性流動)

bull Dislocation are able to migrate through the crystal lattice if the activation energy (活化能) for movement is achieved

bull Distortion of crystal lattice around the dislocation is one source of driving energy as the system tries to achieve a lower internal strain energy

bull Applying a differential stress is another driving mechanism for dislocation motion

Crystal Plasticity (晶體的塑性流動)

bull Associated distortion of solid phases is called crystal plasticity

bull Dislocation movement may occur by glide and a combination of glide and climb (creep)depending mainly on temperature

bull Twinning (双晶 crystal-plastic behavior)occurs at low temperature in some minerals

Crystal Plasticity (晶體的塑性流動)

(1) Dislocation Glide (差排滑動)(2) Cross-slip and climb (側向滑動與爬升) (3) Mechanical Twinning (機械性的雙晶作用)

Dislocation glide (差排滑動)

Dislocation glide(差排滑動)

bull At low temperature dislocations are restricted to glide planes (or slip planes) The glide plane of a dislocation is the plane that contains the Burger vector (b) and the dislocation line (差排線 l) Each edge dislocation has one slip plane because b and l are perpendicular

bull A screw dislocation has many potential slip planes because b and l are parallel

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 11: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Crystal Defects (晶體缺陷)

bull Ductile behavior (韌性行為) of materials at elevated temperature by the motion of crystal defects

bull A crystal defect is an error in the crystal lattice there are three basic types(1) Point defects (點缺陷)(2) Line defects (線缺陷) or dislocations (差排)(3) Planar defects (面缺陷) or stack faults

Crystal Defects (晶體缺陷)bull The motion of defects give rise to permanent

strain without the material losing cohesion (ie without fracturing)

bull Point and line defects are most important for the deformation of rock

bull Planar defects which arise from errors in the internal layering of minerals play only a limited role in deformation

Point defects

(a) Vacancies (空缺)

(b) Substitution (替代雜質)

(c) Interstitials (間隙雜質)

(d) Vacancy migration (空缺遷移)Diffusion

Diffusion (擴散作用)

bull Vacancies can migrate by exchange with atoms in neighboring sites

bull When an atoms moves into a vacant site you can equally say that the vacancy moved

Line Defects or DislocationsDislocation line The boundary between the unslippedand sipped portion of the crystal

Edge dislocation (刃差排)

Screw dislocation(螺旋差排)

Edge dislocation (刃差排)bull Occurs where there is an extra half-plane (多半面) of atoms

in the crystal latticebull Symbol for edge location is or depending on whether

the location of the extra half-plane is above or below the associated gliding plane of the crystal

Screw dislocation (螺旋差排)

bull Atoms are arranged in a corkscrew-like fashion the axis of the screw marks the dislocation line (line CD)

Burgers vector (Burgers 向量)

bull In a deformed crystal an atom-by-atom circuit around the dislocation fails to close by one or more atomic distances while a similar circuit around atoms in a perfect crystal would be complete The arrow connecting the two ends of the incomplete circuit is called Burgers vector

bull The length of Burgers vector in most minerals is on the order of nanometers

Determination of the Burgers vector (伯格向量)

(1) b perpendicular to l(2) Burgers cricuit

remain in the same plane

柏格環路

Determination of the Burgers vector (伯格向量)

(1) b and l are parallel(2) Potential slip plane(3) Glide plane

crystallogrphic plane

柏格環路 Table 91

Mixed dislocations (混合差排)

bull Edge and screw dislocations are only end-member geometries (perfect dislocation) dislocations that consists of part edge and part screw components are called mixed dislocation

Dislocation in olivine

Stress field around an edge dislocation

Wood-split analogy

Shear stress

Interactions between neighboring edge dislocation

(b) Like dislocation on widely separated glide planes may attract or repel depending on the angle between the lines joining the dislocation

(c) Unlike dislocation on the same or nearby glide planes attract

(a) Like dislocation on the same or nearby glide planes repel

Crystal Plasticity (晶體的塑性流動)

bull Dislocation are able to migrate through the crystal lattice if the activation energy (活化能) for movement is achieved

bull Distortion of crystal lattice around the dislocation is one source of driving energy as the system tries to achieve a lower internal strain energy

bull Applying a differential stress is another driving mechanism for dislocation motion

Crystal Plasticity (晶體的塑性流動)

bull Associated distortion of solid phases is called crystal plasticity

bull Dislocation movement may occur by glide and a combination of glide and climb (creep)depending mainly on temperature

bull Twinning (双晶 crystal-plastic behavior)occurs at low temperature in some minerals

Crystal Plasticity (晶體的塑性流動)

(1) Dislocation Glide (差排滑動)(2) Cross-slip and climb (側向滑動與爬升) (3) Mechanical Twinning (機械性的雙晶作用)

Dislocation glide (差排滑動)

Dislocation glide(差排滑動)

bull At low temperature dislocations are restricted to glide planes (or slip planes) The glide plane of a dislocation is the plane that contains the Burger vector (b) and the dislocation line (差排線 l) Each edge dislocation has one slip plane because b and l are perpendicular

bull A screw dislocation has many potential slip planes because b and l are parallel

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 12: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Crystal Defects (晶體缺陷)bull The motion of defects give rise to permanent

strain without the material losing cohesion (ie without fracturing)

bull Point and line defects are most important for the deformation of rock

bull Planar defects which arise from errors in the internal layering of minerals play only a limited role in deformation

Point defects

(a) Vacancies (空缺)

(b) Substitution (替代雜質)

(c) Interstitials (間隙雜質)

(d) Vacancy migration (空缺遷移)Diffusion

Diffusion (擴散作用)

bull Vacancies can migrate by exchange with atoms in neighboring sites

bull When an atoms moves into a vacant site you can equally say that the vacancy moved

Line Defects or DislocationsDislocation line The boundary between the unslippedand sipped portion of the crystal

Edge dislocation (刃差排)

Screw dislocation(螺旋差排)

Edge dislocation (刃差排)bull Occurs where there is an extra half-plane (多半面) of atoms

in the crystal latticebull Symbol for edge location is or depending on whether

the location of the extra half-plane is above or below the associated gliding plane of the crystal

Screw dislocation (螺旋差排)

bull Atoms are arranged in a corkscrew-like fashion the axis of the screw marks the dislocation line (line CD)

Burgers vector (Burgers 向量)

bull In a deformed crystal an atom-by-atom circuit around the dislocation fails to close by one or more atomic distances while a similar circuit around atoms in a perfect crystal would be complete The arrow connecting the two ends of the incomplete circuit is called Burgers vector

bull The length of Burgers vector in most minerals is on the order of nanometers

Determination of the Burgers vector (伯格向量)

(1) b perpendicular to l(2) Burgers cricuit

remain in the same plane

柏格環路

Determination of the Burgers vector (伯格向量)

(1) b and l are parallel(2) Potential slip plane(3) Glide plane

crystallogrphic plane

柏格環路 Table 91

Mixed dislocations (混合差排)

bull Edge and screw dislocations are only end-member geometries (perfect dislocation) dislocations that consists of part edge and part screw components are called mixed dislocation

Dislocation in olivine

Stress field around an edge dislocation

Wood-split analogy

Shear stress

Interactions between neighboring edge dislocation

(b) Like dislocation on widely separated glide planes may attract or repel depending on the angle between the lines joining the dislocation

(c) Unlike dislocation on the same or nearby glide planes attract

(a) Like dislocation on the same or nearby glide planes repel

Crystal Plasticity (晶體的塑性流動)

bull Dislocation are able to migrate through the crystal lattice if the activation energy (活化能) for movement is achieved

bull Distortion of crystal lattice around the dislocation is one source of driving energy as the system tries to achieve a lower internal strain energy

bull Applying a differential stress is another driving mechanism for dislocation motion

Crystal Plasticity (晶體的塑性流動)

bull Associated distortion of solid phases is called crystal plasticity

bull Dislocation movement may occur by glide and a combination of glide and climb (creep)depending mainly on temperature

bull Twinning (双晶 crystal-plastic behavior)occurs at low temperature in some minerals

Crystal Plasticity (晶體的塑性流動)

(1) Dislocation Glide (差排滑動)(2) Cross-slip and climb (側向滑動與爬升) (3) Mechanical Twinning (機械性的雙晶作用)

Dislocation glide (差排滑動)

Dislocation glide(差排滑動)

bull At low temperature dislocations are restricted to glide planes (or slip planes) The glide plane of a dislocation is the plane that contains the Burger vector (b) and the dislocation line (差排線 l) Each edge dislocation has one slip plane because b and l are perpendicular

bull A screw dislocation has many potential slip planes because b and l are parallel

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 13: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Point defects

(a) Vacancies (空缺)

(b) Substitution (替代雜質)

(c) Interstitials (間隙雜質)

(d) Vacancy migration (空缺遷移)Diffusion

Diffusion (擴散作用)

bull Vacancies can migrate by exchange with atoms in neighboring sites

bull When an atoms moves into a vacant site you can equally say that the vacancy moved

Line Defects or DislocationsDislocation line The boundary between the unslippedand sipped portion of the crystal

Edge dislocation (刃差排)

Screw dislocation(螺旋差排)

Edge dislocation (刃差排)bull Occurs where there is an extra half-plane (多半面) of atoms

in the crystal latticebull Symbol for edge location is or depending on whether

the location of the extra half-plane is above or below the associated gliding plane of the crystal

Screw dislocation (螺旋差排)

bull Atoms are arranged in a corkscrew-like fashion the axis of the screw marks the dislocation line (line CD)

Burgers vector (Burgers 向量)

bull In a deformed crystal an atom-by-atom circuit around the dislocation fails to close by one or more atomic distances while a similar circuit around atoms in a perfect crystal would be complete The arrow connecting the two ends of the incomplete circuit is called Burgers vector

bull The length of Burgers vector in most minerals is on the order of nanometers

Determination of the Burgers vector (伯格向量)

(1) b perpendicular to l(2) Burgers cricuit

remain in the same plane

柏格環路

Determination of the Burgers vector (伯格向量)

(1) b and l are parallel(2) Potential slip plane(3) Glide plane

crystallogrphic plane

柏格環路 Table 91

Mixed dislocations (混合差排)

bull Edge and screw dislocations are only end-member geometries (perfect dislocation) dislocations that consists of part edge and part screw components are called mixed dislocation

Dislocation in olivine

Stress field around an edge dislocation

Wood-split analogy

Shear stress

Interactions between neighboring edge dislocation

(b) Like dislocation on widely separated glide planes may attract or repel depending on the angle between the lines joining the dislocation

(c) Unlike dislocation on the same or nearby glide planes attract

(a) Like dislocation on the same or nearby glide planes repel

Crystal Plasticity (晶體的塑性流動)

bull Dislocation are able to migrate through the crystal lattice if the activation energy (活化能) for movement is achieved

bull Distortion of crystal lattice around the dislocation is one source of driving energy as the system tries to achieve a lower internal strain energy

bull Applying a differential stress is another driving mechanism for dislocation motion

Crystal Plasticity (晶體的塑性流動)

bull Associated distortion of solid phases is called crystal plasticity

bull Dislocation movement may occur by glide and a combination of glide and climb (creep)depending mainly on temperature

bull Twinning (双晶 crystal-plastic behavior)occurs at low temperature in some minerals

Crystal Plasticity (晶體的塑性流動)

(1) Dislocation Glide (差排滑動)(2) Cross-slip and climb (側向滑動與爬升) (3) Mechanical Twinning (機械性的雙晶作用)

Dislocation glide (差排滑動)

Dislocation glide(差排滑動)

bull At low temperature dislocations are restricted to glide planes (or slip planes) The glide plane of a dislocation is the plane that contains the Burger vector (b) and the dislocation line (差排線 l) Each edge dislocation has one slip plane because b and l are perpendicular

bull A screw dislocation has many potential slip planes because b and l are parallel

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 14: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Diffusion (擴散作用)

bull Vacancies can migrate by exchange with atoms in neighboring sites

bull When an atoms moves into a vacant site you can equally say that the vacancy moved

Line Defects or DislocationsDislocation line The boundary between the unslippedand sipped portion of the crystal

Edge dislocation (刃差排)

Screw dislocation(螺旋差排)

Edge dislocation (刃差排)bull Occurs where there is an extra half-plane (多半面) of atoms

in the crystal latticebull Symbol for edge location is or depending on whether

the location of the extra half-plane is above or below the associated gliding plane of the crystal

Screw dislocation (螺旋差排)

bull Atoms are arranged in a corkscrew-like fashion the axis of the screw marks the dislocation line (line CD)

Burgers vector (Burgers 向量)

bull In a deformed crystal an atom-by-atom circuit around the dislocation fails to close by one or more atomic distances while a similar circuit around atoms in a perfect crystal would be complete The arrow connecting the two ends of the incomplete circuit is called Burgers vector

bull The length of Burgers vector in most minerals is on the order of nanometers

Determination of the Burgers vector (伯格向量)

(1) b perpendicular to l(2) Burgers cricuit

remain in the same plane

柏格環路

Determination of the Burgers vector (伯格向量)

(1) b and l are parallel(2) Potential slip plane(3) Glide plane

crystallogrphic plane

柏格環路 Table 91

Mixed dislocations (混合差排)

bull Edge and screw dislocations are only end-member geometries (perfect dislocation) dislocations that consists of part edge and part screw components are called mixed dislocation

Dislocation in olivine

Stress field around an edge dislocation

Wood-split analogy

Shear stress

Interactions between neighboring edge dislocation

(b) Like dislocation on widely separated glide planes may attract or repel depending on the angle between the lines joining the dislocation

(c) Unlike dislocation on the same or nearby glide planes attract

(a) Like dislocation on the same or nearby glide planes repel

Crystal Plasticity (晶體的塑性流動)

bull Dislocation are able to migrate through the crystal lattice if the activation energy (活化能) for movement is achieved

bull Distortion of crystal lattice around the dislocation is one source of driving energy as the system tries to achieve a lower internal strain energy

bull Applying a differential stress is another driving mechanism for dislocation motion

Crystal Plasticity (晶體的塑性流動)

bull Associated distortion of solid phases is called crystal plasticity

bull Dislocation movement may occur by glide and a combination of glide and climb (creep)depending mainly on temperature

bull Twinning (双晶 crystal-plastic behavior)occurs at low temperature in some minerals

Crystal Plasticity (晶體的塑性流動)

(1) Dislocation Glide (差排滑動)(2) Cross-slip and climb (側向滑動與爬升) (3) Mechanical Twinning (機械性的雙晶作用)

Dislocation glide (差排滑動)

Dislocation glide(差排滑動)

bull At low temperature dislocations are restricted to glide planes (or slip planes) The glide plane of a dislocation is the plane that contains the Burger vector (b) and the dislocation line (差排線 l) Each edge dislocation has one slip plane because b and l are perpendicular

bull A screw dislocation has many potential slip planes because b and l are parallel

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 15: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Line Defects or DislocationsDislocation line The boundary between the unslippedand sipped portion of the crystal

Edge dislocation (刃差排)

Screw dislocation(螺旋差排)

Edge dislocation (刃差排)bull Occurs where there is an extra half-plane (多半面) of atoms

in the crystal latticebull Symbol for edge location is or depending on whether

the location of the extra half-plane is above or below the associated gliding plane of the crystal

Screw dislocation (螺旋差排)

bull Atoms are arranged in a corkscrew-like fashion the axis of the screw marks the dislocation line (line CD)

Burgers vector (Burgers 向量)

bull In a deformed crystal an atom-by-atom circuit around the dislocation fails to close by one or more atomic distances while a similar circuit around atoms in a perfect crystal would be complete The arrow connecting the two ends of the incomplete circuit is called Burgers vector

bull The length of Burgers vector in most minerals is on the order of nanometers

Determination of the Burgers vector (伯格向量)

(1) b perpendicular to l(2) Burgers cricuit

remain in the same plane

柏格環路

Determination of the Burgers vector (伯格向量)

(1) b and l are parallel(2) Potential slip plane(3) Glide plane

crystallogrphic plane

柏格環路 Table 91

Mixed dislocations (混合差排)

bull Edge and screw dislocations are only end-member geometries (perfect dislocation) dislocations that consists of part edge and part screw components are called mixed dislocation

Dislocation in olivine

Stress field around an edge dislocation

Wood-split analogy

Shear stress

Interactions between neighboring edge dislocation

(b) Like dislocation on widely separated glide planes may attract or repel depending on the angle between the lines joining the dislocation

(c) Unlike dislocation on the same or nearby glide planes attract

(a) Like dislocation on the same or nearby glide planes repel

Crystal Plasticity (晶體的塑性流動)

bull Dislocation are able to migrate through the crystal lattice if the activation energy (活化能) for movement is achieved

bull Distortion of crystal lattice around the dislocation is one source of driving energy as the system tries to achieve a lower internal strain energy

bull Applying a differential stress is another driving mechanism for dislocation motion

Crystal Plasticity (晶體的塑性流動)

bull Associated distortion of solid phases is called crystal plasticity

bull Dislocation movement may occur by glide and a combination of glide and climb (creep)depending mainly on temperature

bull Twinning (双晶 crystal-plastic behavior)occurs at low temperature in some minerals

Crystal Plasticity (晶體的塑性流動)

(1) Dislocation Glide (差排滑動)(2) Cross-slip and climb (側向滑動與爬升) (3) Mechanical Twinning (機械性的雙晶作用)

Dislocation glide (差排滑動)

Dislocation glide(差排滑動)

bull At low temperature dislocations are restricted to glide planes (or slip planes) The glide plane of a dislocation is the plane that contains the Burger vector (b) and the dislocation line (差排線 l) Each edge dislocation has one slip plane because b and l are perpendicular

bull A screw dislocation has many potential slip planes because b and l are parallel

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 16: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Edge dislocation (刃差排)bull Occurs where there is an extra half-plane (多半面) of atoms

in the crystal latticebull Symbol for edge location is or depending on whether

the location of the extra half-plane is above or below the associated gliding plane of the crystal

Screw dislocation (螺旋差排)

bull Atoms are arranged in a corkscrew-like fashion the axis of the screw marks the dislocation line (line CD)

Burgers vector (Burgers 向量)

bull In a deformed crystal an atom-by-atom circuit around the dislocation fails to close by one or more atomic distances while a similar circuit around atoms in a perfect crystal would be complete The arrow connecting the two ends of the incomplete circuit is called Burgers vector

bull The length of Burgers vector in most minerals is on the order of nanometers

Determination of the Burgers vector (伯格向量)

(1) b perpendicular to l(2) Burgers cricuit

remain in the same plane

柏格環路

Determination of the Burgers vector (伯格向量)

(1) b and l are parallel(2) Potential slip plane(3) Glide plane

crystallogrphic plane

柏格環路 Table 91

Mixed dislocations (混合差排)

bull Edge and screw dislocations are only end-member geometries (perfect dislocation) dislocations that consists of part edge and part screw components are called mixed dislocation

Dislocation in olivine

Stress field around an edge dislocation

Wood-split analogy

Shear stress

Interactions between neighboring edge dislocation

(b) Like dislocation on widely separated glide planes may attract or repel depending on the angle between the lines joining the dislocation

(c) Unlike dislocation on the same or nearby glide planes attract

(a) Like dislocation on the same or nearby glide planes repel

Crystal Plasticity (晶體的塑性流動)

bull Dislocation are able to migrate through the crystal lattice if the activation energy (活化能) for movement is achieved

bull Distortion of crystal lattice around the dislocation is one source of driving energy as the system tries to achieve a lower internal strain energy

bull Applying a differential stress is another driving mechanism for dislocation motion

Crystal Plasticity (晶體的塑性流動)

bull Associated distortion of solid phases is called crystal plasticity

bull Dislocation movement may occur by glide and a combination of glide and climb (creep)depending mainly on temperature

bull Twinning (双晶 crystal-plastic behavior)occurs at low temperature in some minerals

Crystal Plasticity (晶體的塑性流動)

(1) Dislocation Glide (差排滑動)(2) Cross-slip and climb (側向滑動與爬升) (3) Mechanical Twinning (機械性的雙晶作用)

Dislocation glide (差排滑動)

Dislocation glide(差排滑動)

bull At low temperature dislocations are restricted to glide planes (or slip planes) The glide plane of a dislocation is the plane that contains the Burger vector (b) and the dislocation line (差排線 l) Each edge dislocation has one slip plane because b and l are perpendicular

bull A screw dislocation has many potential slip planes because b and l are parallel

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 17: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Screw dislocation (螺旋差排)

bull Atoms are arranged in a corkscrew-like fashion the axis of the screw marks the dislocation line (line CD)

Burgers vector (Burgers 向量)

bull In a deformed crystal an atom-by-atom circuit around the dislocation fails to close by one or more atomic distances while a similar circuit around atoms in a perfect crystal would be complete The arrow connecting the two ends of the incomplete circuit is called Burgers vector

bull The length of Burgers vector in most minerals is on the order of nanometers

Determination of the Burgers vector (伯格向量)

(1) b perpendicular to l(2) Burgers cricuit

remain in the same plane

柏格環路

Determination of the Burgers vector (伯格向量)

(1) b and l are parallel(2) Potential slip plane(3) Glide plane

crystallogrphic plane

柏格環路 Table 91

Mixed dislocations (混合差排)

bull Edge and screw dislocations are only end-member geometries (perfect dislocation) dislocations that consists of part edge and part screw components are called mixed dislocation

Dislocation in olivine

Stress field around an edge dislocation

Wood-split analogy

Shear stress

Interactions between neighboring edge dislocation

(b) Like dislocation on widely separated glide planes may attract or repel depending on the angle between the lines joining the dislocation

(c) Unlike dislocation on the same or nearby glide planes attract

(a) Like dislocation on the same or nearby glide planes repel

Crystal Plasticity (晶體的塑性流動)

bull Dislocation are able to migrate through the crystal lattice if the activation energy (活化能) for movement is achieved

bull Distortion of crystal lattice around the dislocation is one source of driving energy as the system tries to achieve a lower internal strain energy

bull Applying a differential stress is another driving mechanism for dislocation motion

Crystal Plasticity (晶體的塑性流動)

bull Associated distortion of solid phases is called crystal plasticity

bull Dislocation movement may occur by glide and a combination of glide and climb (creep)depending mainly on temperature

bull Twinning (双晶 crystal-plastic behavior)occurs at low temperature in some minerals

Crystal Plasticity (晶體的塑性流動)

(1) Dislocation Glide (差排滑動)(2) Cross-slip and climb (側向滑動與爬升) (3) Mechanical Twinning (機械性的雙晶作用)

Dislocation glide (差排滑動)

Dislocation glide(差排滑動)

bull At low temperature dislocations are restricted to glide planes (or slip planes) The glide plane of a dislocation is the plane that contains the Burger vector (b) and the dislocation line (差排線 l) Each edge dislocation has one slip plane because b and l are perpendicular

bull A screw dislocation has many potential slip planes because b and l are parallel

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 18: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Burgers vector (Burgers 向量)

bull In a deformed crystal an atom-by-atom circuit around the dislocation fails to close by one or more atomic distances while a similar circuit around atoms in a perfect crystal would be complete The arrow connecting the two ends of the incomplete circuit is called Burgers vector

bull The length of Burgers vector in most minerals is on the order of nanometers

Determination of the Burgers vector (伯格向量)

(1) b perpendicular to l(2) Burgers cricuit

remain in the same plane

柏格環路

Determination of the Burgers vector (伯格向量)

(1) b and l are parallel(2) Potential slip plane(3) Glide plane

crystallogrphic plane

柏格環路 Table 91

Mixed dislocations (混合差排)

bull Edge and screw dislocations are only end-member geometries (perfect dislocation) dislocations that consists of part edge and part screw components are called mixed dislocation

Dislocation in olivine

Stress field around an edge dislocation

Wood-split analogy

Shear stress

Interactions between neighboring edge dislocation

(b) Like dislocation on widely separated glide planes may attract or repel depending on the angle between the lines joining the dislocation

(c) Unlike dislocation on the same or nearby glide planes attract

(a) Like dislocation on the same or nearby glide planes repel

Crystal Plasticity (晶體的塑性流動)

bull Dislocation are able to migrate through the crystal lattice if the activation energy (活化能) for movement is achieved

bull Distortion of crystal lattice around the dislocation is one source of driving energy as the system tries to achieve a lower internal strain energy

bull Applying a differential stress is another driving mechanism for dislocation motion

Crystal Plasticity (晶體的塑性流動)

bull Associated distortion of solid phases is called crystal plasticity

bull Dislocation movement may occur by glide and a combination of glide and climb (creep)depending mainly on temperature

bull Twinning (双晶 crystal-plastic behavior)occurs at low temperature in some minerals

Crystal Plasticity (晶體的塑性流動)

(1) Dislocation Glide (差排滑動)(2) Cross-slip and climb (側向滑動與爬升) (3) Mechanical Twinning (機械性的雙晶作用)

Dislocation glide (差排滑動)

Dislocation glide(差排滑動)

bull At low temperature dislocations are restricted to glide planes (or slip planes) The glide plane of a dislocation is the plane that contains the Burger vector (b) and the dislocation line (差排線 l) Each edge dislocation has one slip plane because b and l are perpendicular

bull A screw dislocation has many potential slip planes because b and l are parallel

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 19: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Determination of the Burgers vector (伯格向量)

(1) b perpendicular to l(2) Burgers cricuit

remain in the same plane

柏格環路

Determination of the Burgers vector (伯格向量)

(1) b and l are parallel(2) Potential slip plane(3) Glide plane

crystallogrphic plane

柏格環路 Table 91

Mixed dislocations (混合差排)

bull Edge and screw dislocations are only end-member geometries (perfect dislocation) dislocations that consists of part edge and part screw components are called mixed dislocation

Dislocation in olivine

Stress field around an edge dislocation

Wood-split analogy

Shear stress

Interactions between neighboring edge dislocation

(b) Like dislocation on widely separated glide planes may attract or repel depending on the angle between the lines joining the dislocation

(c) Unlike dislocation on the same or nearby glide planes attract

(a) Like dislocation on the same or nearby glide planes repel

Crystal Plasticity (晶體的塑性流動)

bull Dislocation are able to migrate through the crystal lattice if the activation energy (活化能) for movement is achieved

bull Distortion of crystal lattice around the dislocation is one source of driving energy as the system tries to achieve a lower internal strain energy

bull Applying a differential stress is another driving mechanism for dislocation motion

Crystal Plasticity (晶體的塑性流動)

bull Associated distortion of solid phases is called crystal plasticity

bull Dislocation movement may occur by glide and a combination of glide and climb (creep)depending mainly on temperature

bull Twinning (双晶 crystal-plastic behavior)occurs at low temperature in some minerals

Crystal Plasticity (晶體的塑性流動)

(1) Dislocation Glide (差排滑動)(2) Cross-slip and climb (側向滑動與爬升) (3) Mechanical Twinning (機械性的雙晶作用)

Dislocation glide (差排滑動)

Dislocation glide(差排滑動)

bull At low temperature dislocations are restricted to glide planes (or slip planes) The glide plane of a dislocation is the plane that contains the Burger vector (b) and the dislocation line (差排線 l) Each edge dislocation has one slip plane because b and l are perpendicular

bull A screw dislocation has many potential slip planes because b and l are parallel

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 20: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Determination of the Burgers vector (伯格向量)

(1) b and l are parallel(2) Potential slip plane(3) Glide plane

crystallogrphic plane

柏格環路 Table 91

Mixed dislocations (混合差排)

bull Edge and screw dislocations are only end-member geometries (perfect dislocation) dislocations that consists of part edge and part screw components are called mixed dislocation

Dislocation in olivine

Stress field around an edge dislocation

Wood-split analogy

Shear stress

Interactions between neighboring edge dislocation

(b) Like dislocation on widely separated glide planes may attract or repel depending on the angle between the lines joining the dislocation

(c) Unlike dislocation on the same or nearby glide planes attract

(a) Like dislocation on the same or nearby glide planes repel

Crystal Plasticity (晶體的塑性流動)

bull Dislocation are able to migrate through the crystal lattice if the activation energy (活化能) for movement is achieved

bull Distortion of crystal lattice around the dislocation is one source of driving energy as the system tries to achieve a lower internal strain energy

bull Applying a differential stress is another driving mechanism for dislocation motion

Crystal Plasticity (晶體的塑性流動)

bull Associated distortion of solid phases is called crystal plasticity

bull Dislocation movement may occur by glide and a combination of glide and climb (creep)depending mainly on temperature

bull Twinning (双晶 crystal-plastic behavior)occurs at low temperature in some minerals

Crystal Plasticity (晶體的塑性流動)

(1) Dislocation Glide (差排滑動)(2) Cross-slip and climb (側向滑動與爬升) (3) Mechanical Twinning (機械性的雙晶作用)

Dislocation glide (差排滑動)

Dislocation glide(差排滑動)

bull At low temperature dislocations are restricted to glide planes (or slip planes) The glide plane of a dislocation is the plane that contains the Burger vector (b) and the dislocation line (差排線 l) Each edge dislocation has one slip plane because b and l are perpendicular

bull A screw dislocation has many potential slip planes because b and l are parallel

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 21: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Mixed dislocations (混合差排)

bull Edge and screw dislocations are only end-member geometries (perfect dislocation) dislocations that consists of part edge and part screw components are called mixed dislocation

Dislocation in olivine

Stress field around an edge dislocation

Wood-split analogy

Shear stress

Interactions between neighboring edge dislocation

(b) Like dislocation on widely separated glide planes may attract or repel depending on the angle between the lines joining the dislocation

(c) Unlike dislocation on the same or nearby glide planes attract

(a) Like dislocation on the same or nearby glide planes repel

Crystal Plasticity (晶體的塑性流動)

bull Dislocation are able to migrate through the crystal lattice if the activation energy (活化能) for movement is achieved

bull Distortion of crystal lattice around the dislocation is one source of driving energy as the system tries to achieve a lower internal strain energy

bull Applying a differential stress is another driving mechanism for dislocation motion

Crystal Plasticity (晶體的塑性流動)

bull Associated distortion of solid phases is called crystal plasticity

bull Dislocation movement may occur by glide and a combination of glide and climb (creep)depending mainly on temperature

bull Twinning (双晶 crystal-plastic behavior)occurs at low temperature in some minerals

Crystal Plasticity (晶體的塑性流動)

(1) Dislocation Glide (差排滑動)(2) Cross-slip and climb (側向滑動與爬升) (3) Mechanical Twinning (機械性的雙晶作用)

Dislocation glide (差排滑動)

Dislocation glide(差排滑動)

bull At low temperature dislocations are restricted to glide planes (or slip planes) The glide plane of a dislocation is the plane that contains the Burger vector (b) and the dislocation line (差排線 l) Each edge dislocation has one slip plane because b and l are perpendicular

bull A screw dislocation has many potential slip planes because b and l are parallel

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 22: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Dislocation in olivine

Stress field around an edge dislocation

Wood-split analogy

Shear stress

Interactions between neighboring edge dislocation

(b) Like dislocation on widely separated glide planes may attract or repel depending on the angle between the lines joining the dislocation

(c) Unlike dislocation on the same or nearby glide planes attract

(a) Like dislocation on the same or nearby glide planes repel

Crystal Plasticity (晶體的塑性流動)

bull Dislocation are able to migrate through the crystal lattice if the activation energy (活化能) for movement is achieved

bull Distortion of crystal lattice around the dislocation is one source of driving energy as the system tries to achieve a lower internal strain energy

bull Applying a differential stress is another driving mechanism for dislocation motion

Crystal Plasticity (晶體的塑性流動)

bull Associated distortion of solid phases is called crystal plasticity

bull Dislocation movement may occur by glide and a combination of glide and climb (creep)depending mainly on temperature

bull Twinning (双晶 crystal-plastic behavior)occurs at low temperature in some minerals

Crystal Plasticity (晶體的塑性流動)

(1) Dislocation Glide (差排滑動)(2) Cross-slip and climb (側向滑動與爬升) (3) Mechanical Twinning (機械性的雙晶作用)

Dislocation glide (差排滑動)

Dislocation glide(差排滑動)

bull At low temperature dislocations are restricted to glide planes (or slip planes) The glide plane of a dislocation is the plane that contains the Burger vector (b) and the dislocation line (差排線 l) Each edge dislocation has one slip plane because b and l are perpendicular

bull A screw dislocation has many potential slip planes because b and l are parallel

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 23: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Stress field around an edge dislocation

Wood-split analogy

Shear stress

Interactions between neighboring edge dislocation

(b) Like dislocation on widely separated glide planes may attract or repel depending on the angle between the lines joining the dislocation

(c) Unlike dislocation on the same or nearby glide planes attract

(a) Like dislocation on the same or nearby glide planes repel

Crystal Plasticity (晶體的塑性流動)

bull Dislocation are able to migrate through the crystal lattice if the activation energy (活化能) for movement is achieved

bull Distortion of crystal lattice around the dislocation is one source of driving energy as the system tries to achieve a lower internal strain energy

bull Applying a differential stress is another driving mechanism for dislocation motion

Crystal Plasticity (晶體的塑性流動)

bull Associated distortion of solid phases is called crystal plasticity

bull Dislocation movement may occur by glide and a combination of glide and climb (creep)depending mainly on temperature

bull Twinning (双晶 crystal-plastic behavior)occurs at low temperature in some minerals

Crystal Plasticity (晶體的塑性流動)

(1) Dislocation Glide (差排滑動)(2) Cross-slip and climb (側向滑動與爬升) (3) Mechanical Twinning (機械性的雙晶作用)

Dislocation glide (差排滑動)

Dislocation glide(差排滑動)

bull At low temperature dislocations are restricted to glide planes (or slip planes) The glide plane of a dislocation is the plane that contains the Burger vector (b) and the dislocation line (差排線 l) Each edge dislocation has one slip plane because b and l are perpendicular

bull A screw dislocation has many potential slip planes because b and l are parallel

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 24: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Interactions between neighboring edge dislocation

(b) Like dislocation on widely separated glide planes may attract or repel depending on the angle between the lines joining the dislocation

(c) Unlike dislocation on the same or nearby glide planes attract

(a) Like dislocation on the same or nearby glide planes repel

Crystal Plasticity (晶體的塑性流動)

bull Dislocation are able to migrate through the crystal lattice if the activation energy (活化能) for movement is achieved

bull Distortion of crystal lattice around the dislocation is one source of driving energy as the system tries to achieve a lower internal strain energy

bull Applying a differential stress is another driving mechanism for dislocation motion

Crystal Plasticity (晶體的塑性流動)

bull Associated distortion of solid phases is called crystal plasticity

bull Dislocation movement may occur by glide and a combination of glide and climb (creep)depending mainly on temperature

bull Twinning (双晶 crystal-plastic behavior)occurs at low temperature in some minerals

Crystal Plasticity (晶體的塑性流動)

(1) Dislocation Glide (差排滑動)(2) Cross-slip and climb (側向滑動與爬升) (3) Mechanical Twinning (機械性的雙晶作用)

Dislocation glide (差排滑動)

Dislocation glide(差排滑動)

bull At low temperature dislocations are restricted to glide planes (or slip planes) The glide plane of a dislocation is the plane that contains the Burger vector (b) and the dislocation line (差排線 l) Each edge dislocation has one slip plane because b and l are perpendicular

bull A screw dislocation has many potential slip planes because b and l are parallel

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 25: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Crystal Plasticity (晶體的塑性流動)

bull Dislocation are able to migrate through the crystal lattice if the activation energy (活化能) for movement is achieved

bull Distortion of crystal lattice around the dislocation is one source of driving energy as the system tries to achieve a lower internal strain energy

bull Applying a differential stress is another driving mechanism for dislocation motion

Crystal Plasticity (晶體的塑性流動)

bull Associated distortion of solid phases is called crystal plasticity

bull Dislocation movement may occur by glide and a combination of glide and climb (creep)depending mainly on temperature

bull Twinning (双晶 crystal-plastic behavior)occurs at low temperature in some minerals

Crystal Plasticity (晶體的塑性流動)

(1) Dislocation Glide (差排滑動)(2) Cross-slip and climb (側向滑動與爬升) (3) Mechanical Twinning (機械性的雙晶作用)

Dislocation glide (差排滑動)

Dislocation glide(差排滑動)

bull At low temperature dislocations are restricted to glide planes (or slip planes) The glide plane of a dislocation is the plane that contains the Burger vector (b) and the dislocation line (差排線 l) Each edge dislocation has one slip plane because b and l are perpendicular

bull A screw dislocation has many potential slip planes because b and l are parallel

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 26: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Crystal Plasticity (晶體的塑性流動)

bull Associated distortion of solid phases is called crystal plasticity

bull Dislocation movement may occur by glide and a combination of glide and climb (creep)depending mainly on temperature

bull Twinning (双晶 crystal-plastic behavior)occurs at low temperature in some minerals

Crystal Plasticity (晶體的塑性流動)

(1) Dislocation Glide (差排滑動)(2) Cross-slip and climb (側向滑動與爬升) (3) Mechanical Twinning (機械性的雙晶作用)

Dislocation glide (差排滑動)

Dislocation glide(差排滑動)

bull At low temperature dislocations are restricted to glide planes (or slip planes) The glide plane of a dislocation is the plane that contains the Burger vector (b) and the dislocation line (差排線 l) Each edge dislocation has one slip plane because b and l are perpendicular

bull A screw dislocation has many potential slip planes because b and l are parallel

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 27: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Crystal Plasticity (晶體的塑性流動)

(1) Dislocation Glide (差排滑動)(2) Cross-slip and climb (側向滑動與爬升) (3) Mechanical Twinning (機械性的雙晶作用)

Dislocation glide (差排滑動)

Dislocation glide(差排滑動)

bull At low temperature dislocations are restricted to glide planes (or slip planes) The glide plane of a dislocation is the plane that contains the Burger vector (b) and the dislocation line (差排線 l) Each edge dislocation has one slip plane because b and l are perpendicular

bull A screw dislocation has many potential slip planes because b and l are parallel

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 28: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Dislocation glide (差排滑動)

Dislocation glide(差排滑動)

bull At low temperature dislocations are restricted to glide planes (or slip planes) The glide plane of a dislocation is the plane that contains the Burger vector (b) and the dislocation line (差排線 l) Each edge dislocation has one slip plane because b and l are perpendicular

bull A screw dislocation has many potential slip planes because b and l are parallel

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 29: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Dislocation glide(差排滑動)

bull At low temperature dislocations are restricted to glide planes (or slip planes) The glide plane of a dislocation is the plane that contains the Burger vector (b) and the dislocation line (差排線 l) Each edge dislocation has one slip plane because b and l are perpendicular

bull A screw dislocation has many potential slip planes because b and l are parallel

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 30: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

What is the actual process that allows the movement of dislocation

bull Rather than simultaneously breaking all atomic bonds across a plane (fracturing) only bonds along the dislocation line are broken during an increment of movement Less energy required than fracturing

bull Edge dislocation move by successive breaking of bonds under the influence of a minimum stress acting on the gliding plane which is called the critical resolved shear stress (臨界分解剪應力 CRSS)

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 31: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Edge dislocation gliding

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 32: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Pile-ups (堆積)

bull Pile-ups Obstacles that result from the presence of many immobile dislocations

bull In order to overcome these obstacle edge and screw dislocations must move out of there current glide plane which they do by the presence of climb and cross-slip (差排的爬升運動與側向滑動)

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 33: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Cross-slip (側向滑動)

bull Screw dislocation are not confined to a single glide plane because the dislocation line and Burgers vector are parallel thus they can leave one glide plane and move to another glide plane

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 34: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Climb (爬升)

bull Edge dislocation cannot cross-slip because they have only one glide plane They can climb to a different parallel glide plane if there are vacancies to accept the lowest atoms of the extra half-plane

bull The rate of vacancy production increases with rising temperature the efficiency of dislocations climb is temperature dependant

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 35: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Cross-slip of a screw dislocation

(a) Cross-slip of a screw dislocation by diffusion of atoms

(b) Climb of an edge dislocation by diffusion of atoms

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 36: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Dislocation creepbull Dislocation creep is used for the combined

activity of glide and climb

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 37: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Dislocation annihilation (差排的毀滅)One way of reducing the internal strain energy that arise

from lattice distortion in a crystal

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 38: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Calcite twins (方解石雙晶)

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 39: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Growth twins (成長雙晶)

bull Twins that develop during the growth of a crystal little or nothing about the condition of deformation (ie stress and strain)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 40: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is a type of crystal plastic process that involves the glide of partial dislocations

bull A surface imperfection the twin boundary separate two regions of a twinned crystal

bull The lattice in these two portions are mirror images of each other a twin boundary is a mirror plane with a specific crystallographic orientation (Table 92)

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 41: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Mechanical twins(機械雙晶作用)

bull Mechanical twinning is common in low-symmetry minerals such as trigonal (三方)calcite and dolomite and triclinic (三斜)feldspar

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 42: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Mechanical twinning

Twin grain

Twin boundaries

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 43: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Calcite Crystal TwinLayer of Ca

C

O

Angular rotation

partial dislocation

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 44: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Calcite strain-gauge technique

tan p=qγ = Ψ 2 tan( 2)tT

φγ =

1

07 n

ii

tT

γ π=

= sum

Single Twin Multiple twins

twin thickness

grain thickness

1

07 n

ii

tT

γ π=

= sum1

2 tan( 2)n

ii

tT

γ φ=

= sumtan p=qγ = Ψ

2 tan( 2)tT

φγ =

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 45: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Calcite strain-gauge (應變計) method

bull If we measure the total width of twins and the grain size perpendicular to the twin plane we can obtain the total shear strain for a single twinned grain

bull In an aggregate of grains the hear strain will vary as a function of the crystallographic orientation of individual grains relative to bulk strain ellipsoid We use this variation of the principal strain axes by determining the orientations for which the shear strains are zero and maximum

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 46: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Dislocation multiplication in a

Frank-Read source

缺陷形成的原因

一旦形成就生生不息

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 47: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Diffusion Mass Transfer

bull Diffusion flow of rocks occurs by the transfer of material

bull Three diffusion-related deformation mechanisms (1) pressure solution (2) grain-boundary diffusion and (3) volume diffusion

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 48: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Diffusion (擴散作用)Diffusion occurs when an atom (or a point defect) migrates

through a crystal (晶體中的一個原子跳進一個空缺的過程稱為擴散作用) The process is strong temperature dependent because thermal energy causes atoms vibrate facilitating the breaking and reattachment of bonds

2 2R tr= ΓR2 average arear jump distance the distance between atoms in the crystal

structure t timeΓ Jump frequency (單位時間內跳進空缺的原子數目)

Einsteinrsquos equation

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 49: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Diffusion (擴散作用)1 Increasing the temperature of a material

proportionally increases the abilities of individual atoms to jump to neighboring vacant sites

2 Example Fe at melting point (Th=1)Γ (jump frequency)=1010 per secondr (jump distance) 01 nmt= 1 second thus R2 = 01 mm2

3 Geological time t= 1 my (31 x 1013 s) R2 gt 3000 m2

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 50: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Radom-walk process

bull Diffusion is nondirectional in an isotropic stress field so the final distance traveled is distinct from the path and area covered

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 51: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Diffusion Coefficient (擴散係數)

( ) 26D r= Γ

D0 material constant (為材料的常數)E activation energy (打破化學鍵所需的

活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)

0 exp( )D D E RT= minus

擴散係數為單位時間內有原子跳進空缺的面積

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 52: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Volume diffusion and Grain-boundary diffusion

bull 擴散中的空缺若給予足夠的時間則會到達晶體的表面而消失

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散

Grain-bonndary diffusion (Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 53: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)

Diffusional flow by material transport through grains and around grains with a differential stress

Shape change

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 54: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Pressure Solution (壓溶作用)

太麻里 日昇之鄉

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 55: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

石灰岩中的縫合線構造(stylolite)

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 56: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Pressure Solution (壓溶作用)

Pressure solution is a mass transfer process that occurs in natural rocks at temperature much lower that those solid diffusion The process is geometrically similar to grain boundary diffusion but involves the presence of a fluid film on grain boundary

Pressure solution Fluid-assisted diffusion or wet diffusionGrain-boundary diffusion Solid-state diffusion or dry diffusion

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 57: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Pressure solution seams (stylolites) and veins in argillaceous limestone

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 58: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Constitutive Equations of Flow Laws流動定律的組成方程式

( ) exp( )de Af E RTσ= minus

et strain rateA material constant (為材料的常數)E activation energy (打破化學鍵所需的活化能 kJmol)R gas constant (氣體常數 831 Jmol K)T absolute temperature in K (絕對溫度)f(σd) differential stress function (軸差應力函數)

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 59: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律

exp( )exp( )de A E RTσ= minus

For dislocation glide (low temperature creep) the function of stress is exponential

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 60: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Power-law Creep (冪律潛變)

exp( )nde A E RTσ= minus

bull For dislocation glide and climb (high-temperature creep) which is typical for deep crustal and mantle rocks the stress is raised to the power n (stress exponent應力冪數)

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 61: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Limiting stress difference for frictional sliding for different faults

Note that the frictional sliding law is experimental confirmedonly up to pressure corresponding to mid-crust depths

1 3 (1 )gzσ σ βρ λminus ge minusSibson 1974

β parameters depending on the type of faultingβ = 3 for Tβ = 12 for SSβ =075 for Nλ pore fluid factor (ratio of pore fluid pressure to overburden pressure

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 62: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Depth-Strength diagram

exp( )nA Q RTε σ= minus

strain rateσ the differential stress(σ1-σ3)R gas constantT temperatureA n Q material parameters

Experimentally determined flow law for all crust and upper mantle

ε

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 63: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Assumption of geotherms for different tectonic settings

1 Linear variable of T(z) is assumed in the lithosphere from T = 300 K to T = 1500 K at the lower boundary of the tectonic lithosphere

2 Another fixed point is given by T = 1700 K at z = 400 km (top of the mantle transition zone)

Model C cold lithosphere 150 km thinkshield province in continent

Model H hot lithosphere 50 km thick active tectonic province in

continentModel O intermediate lithosphere 75 thick lithosphere mature oceanic province

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 64: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Creep parameters for lithosphere materials

Material A (GPa-ns-1) n Q (kJmol-1)-----------------------------------------------------------------Rocksalt 629 53 102 Granite 18 10-9 32 123Granite (wet) 20 10-4 19 137Quartzite 67 10-6 24 156Quartzite (wet) 32 10-4 23 154Albite rock 26 10-6 39 234Anorthosite 32 10-4 32 238Quartz diorite 13 10-3 24 219Diabase 20 10-4 34 260Peridotite (Olivine) 40 x 104 35 532

Ranalli 1995 see Table 56

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 65: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Rheological profiles of the lithosphereCurves of creep strength vs depth

Note for very small grain size (lt 10-100 μm) andor low stress silicate polycrystals may follow a Newtonian flow law with strain rate linearly proportional to the stress (diffusion creep) rather than the power-law creep

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 66: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Changes in the deformation behavior of quartz aggregates with depth

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 67: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Distribution of the main types of fault rocks with the depth in the crust

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 68: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Synoptic model of a shear zone

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 69: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Individual Defects or Atoms

exp( ) rde A E RT dσ minus= minus

bull If n=1 this means that diffusion is linearly related to the strain rate and diffusional creep is a linear viscous process (Newtonian viscous process線性黏性作用)

bull Strain rate of diffusional creep is nonlinearlyrelated to the grain size Value of r is in the range of 2 to 3

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 70: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

A Microstructural View of Laboratory behavior

bull Rheology (流變學) How material respond to stressbull Steady-state flow generation motion and removal of

dislocation is sufficiently fast to achieve strain at a constant rate for certain stress level

bull Work hardening Limited climb and cross-slip at low temperature prevent dislocations from slipping past inclusions and other obstacles

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 71: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

The formation of a jog from the interaction of two mobile edge dislocations

Dislocation D2 kept stationary while D1 moves

Jog small step due to of one Burgers vector b1

gliding plane

dislocationline

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 72: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Image Dislocation

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 73: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Deformation Microstructures

bull Can we recognize the past activity of a particular deformation mechanism and determine the rheological conditions during deformation

bull Microstructures Geometric characteristics of rocks on the scale of microscope

bull (Micro)fabric (微組構) dimensional-preferred fabric for geometric alignment

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 74: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Recovery (恢復)

bull 恢復(Recovery)與再結晶作用(recrystallization)新結晶作用 (neo-mineralization)

bull Dislocation glide使晶體產生新的缺陷而Recovery 與 recrystallization則是使消除晶體中的缺陷使晶體癒合並使儲存在晶體晶格中的能量減少

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 75: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Irregularly distributed dislocations不規則分佈的刃差排經由滑動與爬升重新排列成差排牆形成傾斜的顆粒邊界分隔次顆粒

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 76: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

傾斜的邊界(tilt boundary)是由刃差排所組成在一個晶格中刃差排之間的距離為h 顆粒邊界兩側的晶格並沒有在同一個方向兩者之間有一個夾角θ(單位為弧角)2sin(θ2)=bh b為Burgers向量當θ角很小時 θ=bh

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 77: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

大理岩糜稜岩中的次顆粒微構造(subgrainmicrostructure)與波狀消光(undulose extinction)

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 78: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Recrystallization (再結晶作用)

bull 變形的顆粒在恢復(recovery)之後再把顆粒內留存的應變能去除的過程稱為再結晶作用這種作用造成高角度的顆粒邊界(high-angle grain boundaries)界開幾乎沒有應變的顆粒 (strain-free grains)

bull 在岩石裡面再結晶顆粒的微構造特徵是顆粒沒有波狀消光(undulatory extinction)邊界相當平直邊界的交角為120o因為這種微構造跟肥皂的泡沫很類似因此也稱為泡沫構造(foam structure)

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 79: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)

bull 在不均勻的應力場(即有軸差應力)中的再結晶作用稱為動態再結晶作用這種動態再結晶作用會造成顆粒尺寸的變小在剪切帶中的岩石(例如mylonite)這種尺寸的變小是很普遍的現象

bull 在均勻的應力場或者軸差應力去除之後的應力場中的再結晶作用稱為靜態再結晶作用或者另稱為Annealing (退火)

bull 靜態再結晶作用與動態再結晶作用的差別在於經過靜態再結晶作用的顆粒會相當地大而且很少有應變能留存

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 80: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

動態再結晶作用(dynamic recrystallization )變形作用時所發生的恢復(Recovery)與再結晶作用

(recrystallization)

退火(annealing)變形作用後所發生的恢復(Recovery)與再結晶作用

(recrystallization)

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 81: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的

顆粒平直的顆粒邊界

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 82: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 83: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Mechanisms of Recrystallization

(1) Rotation recrystallization (旋轉性再結晶作用)

(2) Migration recrystallization (遷移性再結晶作用)

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 84: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Rotation recrystallization (旋轉性再結晶作用)

bull 當越來越多的差排移動到顆粒邊界的差排牆(dislocation wall)形成低角度的顆粒邊界(low-angle tilt boundary) 被差排牆所包圍的次顆粒與其他次顆粒之間晶格不契合的徵象也越明顯因此不用移動顆粒之間的邊界就形成高角度的顆粒邊界(high-angle tilt boundary)

bull 最終次顆粒與其他次顆粒之間晶格不契合的徵象明顯得可以分出次顆粒的邊界當一個顆粒的微構造為中心沒有變形徵象而向外部逐漸由次顆粒轉變為再結晶過的顆粒時這種微構造稱為core-mantle structure 或mortar structure (灰泥牆構造)

bull 旋轉性再結晶作用可以當作是一種同化式的再結晶作用

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 85: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Recrystallization

Subgrain rotation Bulge nucleation

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 86: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Migration recrystallization (遷移性再結晶作用)

bull 一個顆粒將旁邊顆粒的原子納進自己的晶格使其邊界擴展而變成尺寸較大的顆粒(侵略式再結晶作用) 差排密度較低的顆粒消耗掉差排密度較高的顆粒而成長為較大的顆粒

遷移性再結晶作用可以當作是一種侵略式的再結晶作用

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 87: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Core-mantle microstructure or

mortar structure (灰泥牆構造)

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 88: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Empirically derived recrystallized grain size versus differential stress

再結晶礦物顆粒的尺寸與軸差應力大小的關係顆粒的尺寸與軸差應力的大小成反比

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 89: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Superplastic Creep (超塑性潛變)bull Grain-boundary sliding superplasticity (GBSS)的簡稱

原始的定義是指岩石在不產生破裂面的情況下能夠累積很大的應變的能力在這種變形機制中顆粒受到軸差應力的作用使顆粒一方面可以沿著邊界滑動而溫度的效應又可以顆粒內部集體的擴散作用與邊界的擴散作用有效地彌補邊界的滑動所造成的空隙並且使顆粒的滑動不用克服摩擦力而能有效率地滑動(slide without friction)經由超塑性潛變所造成的應變可高達1000以上而顆粒內部卻沒有多少的變形痕跡能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小 (lt 15 μm)

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 90: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Grain-boundary sliding superplasticity (or superplastic creep)

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 91: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Superplastic Creep (超塑性潛變)

能使礦物以這種超塑性潛變進行變形的條件是軸差應力要小溫度要高顆粒要小

因此礦物最初可能經過動態再結晶作用(dynamic recrystalization)使其顆粒變小到足以讓超塑性潛變進行當這種情況產生時岩石變得很軟弱使岩石產生應變的軸差應力就可以很小這種使岩石產生應變的軸差應力降低的作用稱為應變軟化作用(strain softening or work softening)這種應變軟化作用在韌性斷層帶中(ductile fault zone)是一種很普遍的作用

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 92: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Superplastic Creep (超塑性潛變)bull 在超塑性潛變的流動律中應變速率與應力關係的應力函

數差不多是趨近於一個線性關係

bull 即應變速率(ė)是與顆粒的尺寸(d)成反比依據實驗的結果r在2與3之間由於超塑性潛變與顆粒大小有這樣密切的關係因此又稱為Grain-size-dependent creep

re d minuscong

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 93: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Deformation mechanism map for calcite

顆粒尺寸為100μm的方解石變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 94: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Schematic of a Deformation Mechanism Map (變形機制圖)

變形機制圖橫座標為homologous temperature (TTm)縱座標為軸差應力除以剪力模數(shear modulus) (σdG)所得出的正規化應力比

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 95: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Deformation mechanism map for quartz

顆粒尺寸為100μm的石英變形機制圖(a) 沒有壓溶作用伴隨(b) 有壓溶作用伴隨

Volume diffusion (Nabbrro-Herring diffusion)空缺穿過晶體擴散Grain-bonndary diffusion(Coble diffusion)空缺沿著晶體邊緣狹窄的地帶擴散

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 96: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Deformation mechanism map for olivine (橄欖石) with grain size of 100 μm

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 97: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Deformation mechanism map for calcite at T=475oC

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 98: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Closing Remarks

bull 現在的構造地質解釋越來越需要整合各種尺度的觀察在揭開一個岩石與一塊地區的變形歷史時微構造分析(analysis of microstructures) 佔有很重要的地位例如方解石的機械雙晶(mechanical twinning)可以揭開褶皺逆衝帶(fold-and-thrust belt)早期的應力與應變歷史糜稜岩構造(mylonitic microstructures)可以用來估計變形時的溫度狀況軸差應力及應變速率捕獲岩(Xenoliths)中的橄欖石(olivine)可以供給地幔流動(mantle flow)的資訊

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 99: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Deformation Mechanism and Process (變形機制與變形過程) Table 96

過程(P)或機制(M) 原子尺度下的過程

構造特徵

Bulk rotation(M or P) (整體轉動)

礦物顆粒整體地或部分地做機械性的轉動

Helical inclusion trails bending of crystals delta and sigma porphyroclasts

Climb (M) ()

在排差線上原子以擴散的方式加入或移除

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 100: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Diffusive mass transfer (M or P)(集體擴散性的轉移)

原子長程的擴散 Veins pressure shadows porphyroblasts

Dislocation glide(M) (位錯的滑動)

原子間化學鍵重新排列

Deformational lamellae deformation band unduloseextinction

Fracturing (M)(破裂作用)

原子間化學鍵的破裂

Gouge brecciaboudinagedgrains

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 101: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Frictional sliding(M)(摩擦性滑動)

在一個面上做摩擦性的滑動

Gouge breccias pseuotachylytes domino grains

Grain-boundary migration(P or M)(顆粒邊界的遷移)

原子或原子群做局部的擴散或重新定向

Irregular grain boundaries pinning microstructures orientation families lattice-preferred orientations with strong point maximanon-1200

triple junction

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 102: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Grain-boundary sliding(M) (顆粒邊界的滑動)

位錯沿著剛竟乾淨的顆粒邊界運動或沿著髒的顆粒邊界剪動

Kinking(M) (彎折作用)

位錯沿著單一的滑動系統滑動

Kink

Lattice diffusion(M) (晶格的擴散)

Vancncy or interstitials做擴散性的運動

New cystalvoid of preexisting impurities (hard to prove in nature)

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 103: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Lattice rotation(P)(晶格轉動)

位錯滑動以及或顆粒整體轉動

Lattic-preferred orientations

Phase change (P)(相變)

結晶構造改變而整體的化學成分沒有改變

Phase boundaries in minerals

Recovery (P)(復原)

符號相反的位錯的爬升以及相互的殲滅形成次顆粒的牆

Polygonazation foam texture 1200 triple junctions

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 104: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Rotation recrystallization(P)(旋轉性再結晶作用)

相同符號的位錯持續地加到次顆粒的牆壁上

Mortar texture or core-and-mantle texture bimodal grain size

Twinning (M)(雙晶作用)

原子間化學鍵重新排列以及晶格位置的重新定位

Twins shaped-nosed parallel to rational twin planes

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 105: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Assignments

bull Structural Analysis An interactive course for Earth Science Student by Declan G De Paor

bull Chapter 10 Deformation Mechanism(1) DM maps(2) Points defects(3) Line defects(4) Plane defects(5) Recovery

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 106: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Homeworks

bull 945 Where do dislocations come frombull 9101 How to construct a deformation

mechanism map

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite
Page 107: Ductile Deformation(韌性變形 - gl.ntu.edu.t Structures/ES2008... · hand specimen, yet the mechanism of deformation is (micro)fracturing and/or friction sliding. • Cataclasis

Pseudotachylitebull Tachylite is a volcanic rock Early geologists in

Vredefort identified something a bit like it and called it Pseudotachylite It is formed largely by frictional melting along faults or after the impact event Clasts of the country rock (here granite) are found within In these images the Pseudotachylitic breccia is the black stuff

  • Ductile Deformation(韌性變形) Mechanisms
  • How can a strong layer of rock permanently bend into a tight fold
  • Three fundamental mechanisms
  • Which process dominate at a given time in a rockrsquos deformation history
  • Homologous temperature (溫度指標)
  • Cataclastic flow (碎屑流動) Bean bag experiment
  • Cataclastic Flow (碎屑流動)
  • Cataclastic Flow (碎屑流動)
  • Cataclasite (破碎岩)
  • Cataclastic rock (破碎岩)
  • Crystal Defects (晶體缺陷)
  • Crystal Defects (晶體缺陷)
  • Point defects
  • Diffusion (擴散作用)
  • Line Defects or Dislocations
  • Edge dislocation (刃差排)
  • Screw dislocation (螺旋差排)
  • Burgers vector (Burgers 向量)
  • Determination of the Burgers vector (伯格向量)
  • Determination of the Burgers vector (伯格向量)
  • Mixed dislocations (混合差排)
  • Dislocation in olivine
  • Stress field around an edge dislocation
  • Interactions between neighboring edge dislocation
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Crystal Plasticity (晶體的塑性流動)
  • Dislocation glide (差排滑動)
  • Dislocation glide(差排滑動)
  • What is the actual process that allows the movement of dislocation
  • Edge dislocation gliding
  • Pile-ups (堆積)
  • Cross-slip (側向滑動)
  • Climb (爬升)
  • Cross-slip of a screw dislocation
  • Dislocation creep
  • Dislocation annihilation (差排的毀滅)
  • Calcite twins (方解石雙晶)
  • Growth twins (成長雙晶)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twins(機械雙晶作用)
  • Mechanical twinning
  • Calcite Crystal Twin
  • Calcite strain-gauge technique
  • Calcite strain-gauge (應變計) method
  • Dislocation multiplication in a Frank-Read source
  • Diffusion Mass Transfer
  • Diffusion (擴散作用)
  • Diffusion (擴散作用)
  • Radom-walk process
  • Diffusion Coefficient (擴散係數)
  • Volume diffusion and Grain-boundary diffusion
  • Volume Diffusion (Nabarro-Herring creep) and Grain-boundary Diffusion (Coble creep)
  • Pressure Solution (壓溶作用)
  • 石灰岩中的縫合線構造(stylolite)
  • Pressure Solution (壓溶作用)
  • Pressure solution seams (stylolites) and veins in argillaceous limestone
  • Constitutive Equations of Flow Laws流動定律的組成方程式
  • Dislocation glide (exponential creep)差排滑動(低溫潛變)的流動定律
  • Power-law Creep (冪律潛變)
  • Limiting stress difference for frictional sliding for different faults
  • Depth-Strength diagram
  • Assumption of geotherms for different tectonic settings
  • Creep parameters for lithosphere materials
  • Rheological profiles of the lithosphere
  • Changes in the deformation behavior of quartz aggregates with depth
  • Distribution of the main types of fault rocks with the depth in the crust
  • Synoptic model of a shear zone
  • Individual Defects or Atoms
  • A Microstructural View of Laboratory behavior
  • The formation of a jog from the interaction of two mobile edge dislocations
  • Image Dislocation
  • Deformation Microstructures
  • Recovery (恢復)
  • Irregularly distributed dislocations
  • 大理岩糜稜岩中的次顆粒微構造(subgrain microstructure)與波狀消光(undulose extinction)
  • Recrystallization (再結晶作用)
  • 動態再結晶作用(dynamic recrystallization)與靜態再結晶作用(static recrystallization)
  • 動態再結晶作用(dynamic recrystallization ) 變形作用時所發生的恢復(Recovery)與再結晶作用 (recrystallization)退火(annealing) 變形作用後所發生的恢復(Re
  • 大理岩糜稜岩(marble mylonite)中的再結晶微構造(recrystalliztion microstructure)幾乎沒有應變的顆粒平直的顆粒邊界
  • 糜稜岩中的微構造細粒石英顆粒很多的基質包圍著相當剛硬的長石碎屑
  • Mechanisms of Recrystallization
  • Rotation recrystallization (旋轉性再結晶作用)
  • Recrystallization
  • Migration recrystallization (遷移性再結晶作用)
  • Core-mantle microstructure or mortar structure (灰泥牆構造)
  • Empirically derived recrystallized grain size versus differential stress
  • Superplastic Creep (超塑性潛變)
  • Grain-boundary sliding superplasticity (or superplastic creep)
  • Superplastic Creep (超塑性潛變)
  • Superplastic Creep (超塑性潛變)
  • Deformation mechanism map for calcite
  • Schematic of a Deformation Mechanism Map (變形機制圖)
  • Deformation mechanism map for quartz
  • Deformation mechanism map for olivine (橄欖石) with grain size of 100 mm
  • Deformation mechanism map for calcite at T=475oC
  • Closing Remarks
  • Deformation Mechanism and Process (變形機制與變形過程) Table 96
  • Assignments
  • Homeworks
  • Pseudotachylite