The crust is deformed through bending, tilting, and breaking. Isostatic adjustments cause the crust to bend up and down as mountain ranges erode and lighten the crust. Stress in the form of compression, tension, and shearing forces act on rocks in the crust, causing them to be squeezed together, pulled apart, or pushed in opposite directions.

1. Chapter 5
Deformation of the Crust
5.1 How is the crust deformed?
Deformation -
the bending, tilting, and
breaking of the earth’s crust
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2. Isostatic adjustment
Isostasy – the balance between
the forces of the crust pressing
down on the mantle, and the
mantle pressing up on the crust
Isostatic adjustments cause the
crust to bend up and down
Why do isostatic adjustments constantly occur in areas with mountain ranges?

3. Mountain ranges erode.
As the crust lightens, area rises
Rivers can carry large amounts of mud, sand, and gravel.
Glaciers melt, so crust rises

4. Stress
Stress – force that causes pressure in the rocks of the crust
Compression
Rocks are squeezed together
Tension
Force that pulls rocks apart
Shearing
Push rocks in opposite directions
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5. Identify the stress forces on the rocks below...

6. Identify the stress forces on the rocks below...
Shearing

7. Identify the stress forces on the rocks below...
Shearing
Tension

8. Identify the stress forces on the rocks below...
Tension
Shearing
Tension

9. Identify the stress forces on the rocks below...
Compression
Tension
Shearing
Tension