Chapter 15.4Chapter 15.4Deforming the Earth’s CrustDeforming the Earth’s Crust

stressstress• a force that acts on rock deforming it’s

shape or volume

3 typesof stress

shearing tension compression

pushes rock in

opposite directions

pulls on cruststretches rock so that it becomes

thinner in the middle

squeezes rock until it folds

or breaks

YouTube video-Bill Nye Stress

Stress causes rocks to either fold (bend) or fault (break).

Folding

Folded Mountains

• fold-bend in rock that forms when compression shortens & thickens part of Earth’s crust –can create folded Mountains

Three Types of Folds

• Anticline

• Syncline

• Monocline

AAnticlinenticline • fold in rock layers that forms an Arch

Syncline

• fold in rock layers that bends down to form a bowl –SMILEY FACE!

Anticline & syncline

Anticline & syncline

Monocline

• Rock layers are folded so that both ends of the fold are horizontal.

3 typesof faults

strike-slip normal reverse

caused by shearing

caused bytension

caused bycompression

Hanging Wall/Footwall

Normal fault

hanging wall

footwall

hanging wall moves down relative to the footwall

Normal Faults

Reverse faulthanging wall moves up relative to the footwall

footwall

hanging wall

Reverse Fault

Strike-Slip Fault

• Faulting at a transform boundary – fault blocks slide past each other

What kind of fault is this?strike-slip fault

San Andreas fault

Example of a strike-slip fault

Fault-Block Mountains

• mountains formed when normal faults cause large blocks of rocks to slip down due to tension

Grand Teton mountain range

fault-block fault-block mountainmountain

Uplift and Subsidence• Vertical movements in the crust are

divided into two types—– Uplift – the rising of regions of the Earth’s

crust to higher elevations (mountains and rebound – slow movement back to normal level after weight is removed)

– Subsidence – sinking of regions of Earth’s crust to lower elevations (rift zones and oceanic crust as it moves away from the ridge)

plateauplateau= large area of flat land elevated high above sea level (an area of uplift)

• The Colorado Plateau is a 150,000 square mile region covering parts of Arizona, Utah, Colorado, and New Mexico.

syncline

• What is a fold in rock layers that bends down to form a bowl ?

syncline

syncline

fold

What is a bend in rock that forms when compression shortens & thickens part of Earth’s crust ?

A fold is a bend in rock that forms when compression shortens & thickens part of Earth’s crust.

A fold is a bend in rock that forms when compression shortens & thickens part of Earth’s crust.

fault-block mountain• What is a mountain formed when normal faults cause a block of rock to slip down?

Sierra-Nevada mountain range

aanticline nticline

• What is a fold in rock layers that forms an arch ?

• In a _____________

fault, the rocks on either side of the fault slip past each other sideways.

• In a strike-slip fault, the rocks on either side of the fault slip past each other sideways.

What are the 3 types

of stress ?

shearing tension compression

• The 3 types of stress are shearing, tension and compression.

• The 3 types of stress are shearing, tension and compression.

tensiontensionWhat type of stress pulls on the

crust, stretching the rock so that it becomes thinner in the middle ?

B. shearingB. shearing

• What type of stress pushes rock in opposite directions?

A. tensionA. tension

What are the 3 types of faults?What are the 3 types of faults?

1. strike-slip2. normal3. reverse

What type of fault is caused by shearing?

A.A. Strike-slipStrike-slipB.B. NormalNormalC.C. ReverseReverseD.D. Fault-blockFault-block