1. Chapter 7
Plate Tectonics

2. Chap 7, Sec 4 (Deforming the Earth’s Crust)
Objectives:
Describe the three types of stress (force) that deform rocks.
Explain the differences between the three major types of faults.

3. Tech Terms:
deformation – the change in the shape of rock in response to stress.
stress – a force that acts on rock to change its shape or volume.

4. 3 types of stress:
shearing –when rock is pushed in opposite directions
tension - pulls on the crust, stretching rock so it becomes thinner in the middle
compression – squeezes rock until it folds or breaks

7. 3 types of faults:
3. normal fault – tension creates this fault at divergent boundaries, causing rock to pull apart (the footwall slides up and the hanging wall slides down). Occur along the Rio Grande rift valley.

8. Normal Fault

9. 4. reverse fault – compression creates this fault at convergent boundaries, causing rock to compact (the footwall slides down and the hanging wall slides up). Occurs along the Appalachian Mountains.

10. Reverse Fault

11. 5. strike-slip fault – shearing creates this fault at transform boundaries, which causes rock to move past each other in opposite directions. Occurs along the San Andreas Fault in California.

12. Strike Slip Fault