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