Title Page-pg. 43

Chapter 11 Deformation of the Crust• 3 pictures• 3 keyword• 3 colors

• Which type of fault motion best matches the general pattern of crustal movement at California’s San Andreas Fault?

A. Diagram 1B. Diagram 2C. Diagram 3D. Diagram 4

In: pg. 44

• Deformation means to change shape, to go away from the normal What are 3 examples of deformation of the

Earth’s crust?

StressAmount of

force per area put on an object

Rocks can change

shape due to stress

StressStress-The squeezing, stretching and twisting of the Earth’s crust.

Isostasy

• Isostasy-The balance between the downward pull of gravity on the lithosphere and the upward push of the asthenosphere.

• If the mass of the crust increases, it sinks.–New mountains, glaciers, sediment

deposition• If the mass of the crust decreases, it rises.– Erosion of mountains, melting of glaciers

a. The weight of the crust pushes down on the asthenosphere.

b. As the mountain erodes away, the crust gets lighter and rises. The deposition of sediments causes the crust to sink.

Three types of stress:

Compression

Tension

Shear

StressTypes of stress:• Compression-Pushing together • Tension-Pulling apart • Shear stress- sliding in opposite

directions

FOLDINGRock layers bend

due to stressAssume most rocks are laid

down horizontal

FoldsFold-bend in rock layers.• Happen below the earth’s surface where it is

warmerAnticline-folds upwardsSyncline-folds downwards

FAULTSThe line

along which rocks break and move

Faults

• Hanging wall-The rock above the fault• Foot wall-The rock below the fault

Normal FaultsCaused

by tension forces

Hanging wall

moves down

Reverse Faults

Caused by compression forces

Hanging wall moves up

Strike-slip Faults

Opposing forces cause rock to

breakMove

horizontally

Types of Faults•Normal Fault-hanging wall

move down, footwall moves up.–Caused by tension stress

• Reverse Fault-hanging wall moves up, footwall move down.–Caused by compression stress

• Strike Slip Fault-rock on either side of the fault slides horizontally past each other in opposite directions.–Caused by shearing stress

Follow-Up Questions

1.Does the shape of the marshmallow lengthen during compression or tension stress?

2.What happens to the shape of the marshmallow during shear stress?

3.Describe the differences between the three types of stresses that can occur to rocks as the lithosphere moves.

Answers1.Tension stress.

2.Shear stress pulls the marshmallow in more than one direction.

3.Compression stress squeezes and shortens rocks, tension stress pulls rocks apart, and shear stress distorts the shapes of rocks.

How Mountains FormMountain Range-A group of mountains that are close together and formed together.

example: Cascade Range, Great Smokey Mountains, Rocky Mountains

Mountain System-A group of mountain ranges that are close to each other.Example: The Appalachian Mountain system.

Thru 2

Pg. 46Ch. 11 3 Column Vocab1. Deformation2. Isostasy3. Stress4. Compression5. Tension6. Shear stress7. Fold

Pg. 478. Anticline9. Syncline10. Fault11. Footwall12. Hanging wall13. Mountain range14. Mountain system**Not all words are in glossary, some are italicized in the chapter or in notes.

Out

• Less than five million years ago, the range that we now know as the Sierra Nevada began to rise. Through a combination of uplift of the Sierran block and down-dropping of the area to the east, the Sierra rose upward. The entire Sierra Nevada can be thought of as an enormous tilted fault block mountain with a long, gentle slope westward to California's Central Valley and steep eastern slope towards Nevada.

1. When did the Sierra Nevadas start to uplift?

2. Where are the Sierra Nevadas located?

3. What type of mountains are the Sierra Nevada Mountains?

InUse your notes to answer these questions.1. _______ is the balance between the crust and the

asthenosphere.2. If a mountain is eroded away, will the crust move up or down?3. What are the 3 types of stress?4. _______ stress results in rock being pushed together.5. What are the 2 types of folds?6. A _______ fault is caused by compression stress.7. In a _______fault, the rock on either side of the fault slides

horizontally in opposite directions.8. The Rocky Mountains are an example of a mountain_______.9. What are the 4 types of mountains?10. Which type of mountain forms from compression stress?

Thru 1: Pg. 49

Movie: Shaping the Planet