Essentials of Geology, 9e Crustal Deformation and Mountain Building Chapter 17.
CHAPTER 11 MOUNTAIN BUILDING
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Transcript of CHAPTER 11 MOUNTAIN BUILDING
CHAPTER 11 MOUNTAIN BUILDING
Roots: Erg = work (energy)Aesth = feeling (aesthetic)Ethno = race (ethnic)Eu = good (euphoria)Ex = out (exit)Extra = outside (extraterrestrial)Fact = make (artifact)Fer = carry (ferry)Fid = faith (confide)Flect = bend (deflect)
CH. 11.1 ROCK DEFORMATIONMostly happens at Plate Boundaries.
Deformation = all changes in the original shape and/or size of a rock body.
What affects whether a rock will deform?:• temperature• confining pressures• rock type• time
Temperature & Pressure
Brittle Deformation
• Deform when near the surface.• Deform under lower temperatures and
pressures.• Break instead of folding.
Temperature & Pressure
Ductile Deformation
• Deform at depth.• Deform under higher temperatures and
pressures.• Fold, bend and flatten.
Rock Type
Rocks like granite and basalt that are made of strong
structures usually fail by brittle deformation.
Rocks made of weaker sedimentary rocks usually fail by ductile deformation.
Time
Forces that are unable to deform rock at first may be able to affect a change over long periods of time.
For example, marble benches have been
known to bend under their own weight over
hundreds of years.
TYPES OF STRESS!
Compressional Stress = rocks are squeezed.
Tensional Stress = rocks are pulled apart.
Shear Stress = rocks are distorted.
Types of Folds
Monocline = step-like Anticline = arching
Syncline = trough-like
Monocline, Anticline, or Syncline? You decide!
MonoclineSynclineSyncline
Anticline
SynclineAnticline
Faults
Normal = hanging wall drops Reverse = hanging wall lifts
Thrust = reverse of < 45o Strike-slip = horizontal movement
Joints = no movement
CH 11.2 Types of Mountains
FOLDED MOUNTAINS
Formed primarily by folding.Most often associated with compression.
Fault-Block Mountains = large scale normal faults
GrabenHorst
Dome Mountains = circular or elongated structure produced by upwarping.
Basin = circular shape produced by downwarping.
CH 11.3 Mountain Formation
Mountain Buildinghttp://www.learner.org/vod/vod_window.html?pid=318
Mostly convergent boundary formations.
Accretion = when crustal fragments collide with a continental plate and become stuck to or embedded into the plate.
Himalayan MountainsFormed when India collided with southern Asia
GoogleEarth all the way down and show Mt Everest from above and side views.
Google earth mid atlantic ridge go all the way to the base and turn up then scan horizon
Divergent Mountains = mountains built at divergent boundaries
Example: Mid-Atlantic ridge
Continental Accretion - Terranehttp://www.geology.um.maine.edu/geodynamics/analogwebsite/UndergradProjects2005/Perry/html/introduction.html
Terrane = crustal fragment that has a geologic history distinct from the rocks around it.
Figure 16Pg 322
Isostasy = the gravitational balance of floating continental plates.
Floating block interactive animationhttp://www.ikswonad.com/portfolio/index.php?show=isostasy
Mountains of the World
Rockies
Andies
Himalayas
AppalachiansAlps
Urals
Zagros
Atlas
Great Dividing Range
AlpsAndies
Appalachians
AtlasGreat Dividing Range
RockiesUrals
ZagrosHimalayas