That

all

aspe

cts o

f stru

ctur

al g

eolo

gy &

te

cton

ics a

re in

trins

ical

ly c

onne

cted

Mic

rost

ruct

ures

link

stru

ctur

al g

eolo

gy &

te

cton

ics t

o ot

her g

eolo

gic

disc

iplin

es**

To c

onfr

ont t

he d

iffer

ence

bet

wee

n th

e cu

rren

t rig

id c

hara

cter

of r

ock

& it

s for

mer

duc

tility

&

ther

eby

inte

grat

e th

eir o

bser

vatio

ns a

cros

s tim

e

Parti

cula

r com

bina

tions

of r

ock

type

, te

mpe

ratu

re, p

ress

ure,

por

e flu

id p

ress

ure,

flu

id p

hase

com

posi

tion,

etc

. yie

ld

char

acte

ristic

suite

s of m

icro

stru

ctur

es

To in

fer r

ock

beha

vior

& p

redi

ct re

ason

able

co

mbi

natio

ns o

f diff

eren

tial s

tress

& st

rain

rate

at

diff

eren

t tim

es in

a te

cton

ic h

isto

ry

Mat

hem

atic

al e

xpre

ssio

ns d

escr

ibe

&

enca

psul

ate

rock

rheo

logy

That

they

can

infe

r roc

k be

havi

or fr

om

mic

rost

ruct

ural

obse

rvat

ions

eve

n th

ough

they

ca

n’t o

bser

ve d

efor

mat

ion

in re

al ti

me

Roc

k rh

eolo

gyde

pend

s upo

n w

hich

de

form

atio

n m

echa

nism

pre

dom

inat

e

How

thei

r ow

n ob

serv

atio

ns c

an c

onst

rain

in

fere

nces

of c

ondi

tions

at k

ey p

oint

s dur

ing

a te

cton

ic h

isto

ry

Roc

ks d

efor

med

und

er d

iffer

ent c

ondi

tions

de

velo

p di

ffer

ent s

uite

s of m

icro

stru

ctur

es

Why

thei

r obs

erva

tions

of g

rain

-sca

le &

han

d-sa

mpl

e sc

ale

feat

ures

are

sign

ifica

ntD

iffer

ent d

efor

mat

ion

mec

hani

sm p

redo

min

ate

at d

iffer

ent c

ondi

tions

To in

tegr

ate

defo

rmat

ion

acro

ss a

rang

e of

le

ngth

scal

esA

ll m

acro

scop

ic d

efor

mat

ion

is a

ccom

plis

hed

by m

icro

scop

ic, g

rain

-sca

le p

roce

sses

TH

EN

ST

UD

EN

TS

LE

AR

N …

..IF

YO

U T

EA

CH

TH

AT

……

.,

Onl

y 50

% o

f the

70

stru

ctur

al g

eolo

gist

s sur

veye

d at

the

rece

nt C

uttin

g Ed

ge w

orks

hop

on T

each

ing

Stru

ctur

al G

eolo

gy in

the

21st

Cen

tury

incl

ude

grai

n-sc

ale

defo

rmat

ion

mec

hani

sms,

mic

rost

ruct

ures

, and

rheo

logy

in th

eir c

ours

es, y

et th

e ca

se fo

r inc

ludi

ng th

ese

topi

cs is

stro

ng. F

unda

men

tally

, mic

rosc

opic

pro

cess

es a

ccom

plis

h al

l mac

rosc

opic

def

orm

atio

n. T

here

are

onl

y a

few

dist

inct

gra

in-s

cale

def

orm

atio

n m

echa

nism

s; e

ach

one

dom

inat

es a

t diff

eren

t P,T

con

ditio

ns, p

rodu

ces c

hara

cter

istic

mic

rostr

uctu

res,

and

has a

diff

eren

t for

m o

f con

stitu

tive

rela

tion

betw

een

stre

ss a

nd st

rain

or s

train

rate

. Und

erst

andi

ng th

e di

ffer

ent m

echa

nism

s inf

orm

s the

mos

t fun

dam

enta

l que

stio

ns in

our

dis

cipl

ine.

Inte

rpre

tatio

n of

the

mic

rost

ruct

ures

pre

serv

ed in

de

form

ed ro

cks a

llow

s us t

o in

fer t

he p

hysi

cal c

ondi

tions

and

his

tory

of d

efor

mat

ion.

Kno

wle

dge

of ro

ck rh

eolo

gyal

low

s us t

o pr

edic

t the

def

orm

atio

n st

yle

and

rock

stre

ngth

indi

ffer

ent

tect

onic

setti

ngs,

and

prov

ides

crit

ical

inpu

t to

geod

ynam

ics q

uest

ions

. Th

e st

udy

of d

efor

mat

ion

mec

hani

sms,

mic

rost

ruct

ures

and

rheo

logy

allo

ws s

tude

nts t

o co

rrel

ate

grai

n-sc

ale

feat

ures

and

pro

cess

es to

thos

e de

velo

ped

at h

and

sam

ple,

out

crop

and

re

gion

al sc

ales

, and

to c

onfro

nt h

ow d

efor

mat

ion

rate

s rel

ate

toro

ck st

reng

th a

t diff

eren

t dep

ths i

n th

e cr

ust.

Stud

ents

trai

ned

to re

cogn

ize

and

unde

rsta

nd th

e ac

tual

pro

cess

es o

f bot

h br

ittle

and

du

ctile

def

orm

atio

n ar

e be

tter a

ble

to c

ritic

ally

ana

lyze

the

bulk

beh

avio

r of r

ocks

in d

iffer

ent g

eolo

gic

setti

ngs.

To fa

cilit

ate

the

inco

rpor

atio

n of

def

orm

atio

n m

echa

nism

s and

mic

rost

ruct

ures

into

stru

ctur

al g

eolo

gy c

ours

es, o

ur w

orki

ng g

roup

has d

evel

oped

shor

t tea

chin

g m

odul

es o

n cr

itica

l co

ncep

ts (e

.g. c

atac

last

icflo

w, d

iffus

ion

and

pres

sure

solu

tion,

dis

loca

tion

cree

p) th

at c

an b

e in

corp

orat

ed in

to e

xist

ing

cour

ses d

urin

g di

scus

sion

of r

elat

ed to

pics

(e.g

. fau

lts, f

olia

tions

, fol

ds).

Thes

e m

odul

es in

clud

e in

stru

ctor

’s n

otes

, key

dia

gram

s, an

nota

ted

phot

os, p

ossi

ble

hand

outs

, and

idea

s for

cla

ss o

r lab

dem

onst

ratio

ns a

nd a

ctiv

ities

. The

mod

ules

and

supp

lem

enta

l res

ourc

es

(e.g

. ani

mat

ions

, ana

logs

, arti

cles

) can

be

foun

d at

http

://se

rc.c

arle

ton.

edu/

NA

GTW

orks

hops

/stru

ctur

e04.

Add

ition

al c

ontri

butio

ns to

this

reso

urce

ban

k fr

om a

ll ge

osci

entis

ts a

re w

elco

me.

Abs

trac

t

Our

Man

ifest

o

I.In

stru

ctor

’s n

otes

II.C

lass

room

han

dout

sII

I.In-

clas

s dem

os &

act

iviti

esIV

.Add

ition

al re

sour

ces

To

mak

e it

poss

ible

, in

tere

stin

g an

d ev

en fu

n fo

r yo

u to

in

corp

orat

e m

icro

stru

ctur

es a

nd

defo

rmat

ion

mec

hani

sms

into

you

r st

ruct

ural

ge

olog

y co

urse

s!

The

Mod

ules

Our

Goa

l

Many thanks to our colleagues from the Teaching Structural Geology in the 21stCentury Workshop!

LA-UR-04-6084

JAN

TU

LL

IS,D

ept.

Geo

logi

cal S

cien

ces,

Bro

wn

Uni

v, P

rovi

denc

e, R

I 029

12; P

AT

RIC

IA C

AM

PBE

LL,

Dep

t. G

eogr

aphy

, Geo

logy

and

Env

ironm

ent,

Slip

pery

Roc

k U

niv,

Shi

ppen

sbur

g,

PA 1

6057

; JU

LIE

T C

RID

ER

, Dep

t. G

eolo

gy, W

este

rn W

ashi

ngto

n U

nive

rsity

, Bel

lingh

am, W

A, 9

8225

; DY

AN

NA

CZE

CK

, Dep

t. G

eosc

ienc

es, U

niv

of W

isco

nsin

-M

ilwau

kee,

M

ilwau

kee,

WI 5

3201

; TE

KL

A H

AR

MS,

Dep

t. of

Geo

logy

, Am

hers

t Col

lege

, Am

hers

t, M

A, 0

1002

; MIC

HA

EL

HA

RR

ISO

N, D

ept.

of E

arth

Sci

ence

s, Te

nnes

see

Tech

Uni

v, C

ooke

ville

, TN

385

05-0

001;

CH

RIS

KO

PF, D

ept.

Geo

logi

cal S

cien

ces,

Uni

v. N

orth

Car

olin

a, C

hape

l Hill

, NC

275

99; C

AR

OL

OR

MA

ND

, Dep

t. G

eolo

gy, W

itten

berg

Uni

v, S

prin

gfie

ld, O

H 4

5501

; L

IND

A R

EIN

EN

, Dep

t. G

eolo

gy, P

omon

a C

olle

ge, C

lare

mon

t, C

A 9

1711

; AV

IVA

SU

SSM

AN

, MS

D46

2, L

os A

lam

os N

atio

nal L

abor

ator

y, L

os A

lam

os, N

M 8

7545

;BE

TSY

TO

RR

EZ,

D

ept.

Geo

grap

hy a

nd G

eolo

gy, S

am H

oust

on S

tate

Uni

v, H

unts

ville

, TX

773

41; S

TE

VE

WO

JTA

L, D

ept.

Geo

logy

, Obe

rlin

Col

lege

, Obe

rlin,

OH

440

74

1.Te

ach

abou

t mic

rost

ruct

ures

in y

our c

lass

es!

2.Sh

are

your

idea

s with

us!

3.Pr

ovid

e us

with

add

ition

al re

sour

ces

1.Sl

ides

from

PPT

pre

sent

atio

ns o

n D

efor

mat

ion

Twin

ning

Mec

hani

cal

Mec

hani

cal T

win

ning

Tw

inni

ng

Sim

ple

shea

r of

par

t of

Si

mpl

e sh

ear

of p

art

of

the

crys

tal l

attic

e al

ong

a th

e cr

ysta

l lat

tice

alon

g a

crys

tallo

grap

hic

plan

ecr

ysta

llogr

aphi

c pl

ane

Resu

lts in

sym

met

ry o

f Re

sults

in s

ymm

etry

of

the

crys

tal l

attic

e ac

ross

th

e cr

ysta

l lat

tice

acro

ss

the

twin

pla

neth

e tw

in p

lane

Geo

met

ry o

f e-t

win

s in

calc

ite

(aft

er C

arte

r &

Ral

eigh

, 196

9)

Acco

mpl

ishe

s a

fixed

am

ount

of

shea

r Ac

com

plis

hes

a fix

ed a

mou

nt o

f sh

ear

stra

in (

cont

rolle

d by

the

cry

stal

logr

aphy

st

rain

(co

ntro

lled

by t

he c

ryst

allo

grap

hy

of t

he m

iner

al)

of t

he m

iner

al)

Occ

urs

whe

n th

e sh

ear

stre

ss a

long

the

O

ccur

s w

hen

the

shea

r st

ress

alo

ng t

he

twin

pla

ne e

xcee

ds a

crit

ical

val

uetw

in p

lane

exc

eeds

a c

ritic

al v

alue

Com

mon

ly f

ound

in c

alci

te, do

lom

ite,

Com

mon

ly f

ound

in c

alci

te, do

lom

ite,

and

plag

iocl

ase

(but

occ

urs

in m

any

othe

r an

d pl

agio

clas

e (b

ut o

ccur

s in

man

y ot

her

min

eral

s)m

iner

als)

Mic

rosc

opic

ally

, M

icro

scop

ical

ly,

twin

lam

ella

e tw

in la

mel

lae

appe

ar a

s th

in,

appe

ar a

s th

in,

dark

, par

alle

l lin

es,

dark

, par

alle

l lin

es,

or a

s pa

ralle

l ban

ds

or a

s pa

ralle

l ban

ds

of a

ltern

atin

g of

alte

rnat

ing

extin

ctio

n co

lors

extin

ctio

n co

lors

Mic

rost

ruct

ures

Pro

duce

d:M

icro

stru

ctur

es P

rodu

ced:

twin

lam

ella

etw

in la

mel

lae

2. S

lides

from

PPT

pre

sent

atio

ns o

n D

iffus

ive

Mas

s Tra

nsfe

r

3. P

ages

from

Stu

dent

Han

dout

s on

Dis

loca

tion

Cre

ep

Diffu

sion

alpa

ths

•Diffu

sion

thr

ough

agg

rega

te m

ay o

ccur

along

the

followi

ng p

aths

:–

As

latt

ice

diff

usion

thro

ugh

the

latt

ices

of

the

grains

tha

t mak

e up

the

agg

rega

te–

As

grain

boun

dary

diffu

sion

alon

g th

e bo

unda

ries

bet

ween

gr

ains

in

the

aggr

egat

e–

As

free

sur

face

diffu

sion

alon

g th

e inte

rfac

e be

twee

n a

pore

fluid

& th

e miner

al g

rains

–As

free

fluid

diffu

sion

thro

ugh

fluid-

fille

d po

res

•Lo

oking

only a

t en

d re

sult,

one

cann

ot d

isting

uish

by

which

path

mat

erial m

oved

•Bu

t, s

ince

diffu

sion

rat

es inc

reas

e dr

amat

ically w

ith

the

addi

tion

of

a f

luid p

hase

, po

re f

luids

will

enha

nce

mat

erial re

arra

ngem

ent

by d

iffu

sion

Exam

ples

Get

ting

Invo

lved

Our

web

site

will

incl

ude

(1) t

each

ing

mod

ules

on:

A.a

n ov

ervi

ew o

f def

orm

atio

n m

echa

nism

sB

.dis

loca

tion

cree

pC

.diff

usio

n cr

eep/

diff

usio

nalm

ass t

rans

fer

D.d

efor

mat

ion

twin

ning

E.cr

ack

form

atio

n, c

oale

scen

ce, p

ropa

gatio

nF.

cata

clas

ticflo

wG

.ass

essm

ent o

f the

rela

tive

impo

rtanc

e of

diff

eren

t m

echa

nism

s & d

efor

mat

ion

mec

hani

sm m

aps

(2) a

dditi

onal

reso

urce

s (in

clud

ing:

inst

ruct

or’s

not

es, P

ower

Poin

t pr

esen

tatio

ns, d

igita

l im

ages

, vid

eos,

anim

atio

ns, c

lass

dem

os,

artic

les a

ppro

pria

te fo

r und

ergr

adua

tes)

acc

essi

ble

via

topi

cal,

web

-bas

ed se

arch

es.

http

://w

ww

-odp

.tam

u.ed

u/pu

blic

atio

ns/1

80_S

R/1

78/1

78_p

3.ht

m

cata

clas

ite

http

://w

ww

.ucl

.ac.

uk/~

ucfb

rxs/

PLM

/cal

cite

.htm

l

calc

ite tw

ins

selv

ages

and

qua

rtz

fiber

s on

mag

netit

e gr

ains

The

Web

site

mic

a fis

h &

obl

ique

elo

ngat

e re

crys

talli

zed

quar

tz g

rain

s in

quar

tz m

ylon

itein

dica

ting

dext

ral s

hear

http

://im

ages

.goo

gle.

com

/imgr

es?i

mgu

rl=h

ttp:

//ww

w.v

irtu

alex

plor

er.c

om

.au/

VE

jour

nal/2

000V

olum

es/V

olum

e2/w

ww

/con

trib

s/tu

llis/

Slid

es/

mic

rocr

acks

with

in a

cat

acla

site

zone

http

://w

ww

.vir

tual

expl

orer

.com

.au/

VE

jour

nal/2

000V

olum

es/V

olum

e2/w

ww

/con

trib

s/tu

llis/

Slid

es/

4. S

elec

tions

from

Inst

ruct

or’s

Not

es o

n Fr

actu

res

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