Chapter 7 Plate Tectonics

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.

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.

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

3 types of faults: 3. normal fault – tension creates this fault at divergent boundaries. Occur along the Rio Grande rift valley.

4. reverse fault – compression creates this fault at convergent boundaries. Occurs along the Appalachian Mountains.

5. strike-slip fault – shearing creates this fault at transform boundaries. Occurs along the San Andreas Fault in California.