1. Chapter 7 Plate Tectonics

2. Chap 7, Sec 3 (The Theory of Plate Tectonics) What we will learn: 1.Describe the 3 types of plate boundaries. 2.Explain the difference between the 3 types of faults. 3.Describe the 3 types of stress that deform rock.

3. Vocab: 1.plates – separate sections of the lithosphere. 2.plate tectonics –theory that states that pieces of lithosphere are in constant motion, driven by convection currents in the mantle.

5. 3.faults – breaks in Earth’s crust where plate boundaries form.

6. 4.transform boundary – a place where two plates slide past each other in opposite directions (earthquakes are frequent).

8. 5.divergent boundary – the place where two plates move apart, or dive away (most occur at the mid- ocean ridge). 6.rift valley – develops on land, where two plates diverge.

9. Mid Ocean Ridge

11. 7.convergent boundary – the place where two plates come together, or collide. (the density of the plates dictates which one comes out on top). Ex: at the deep ocean trench where the oceanic crust (basalt) is more dense than the continental crust (granite) which is less dense

12. Subduction

13. Types of Stress Deformation: Process that changes the shape of rock because of stress. Tension: stress that forms when forces act to stretch an object (rubber band) Compression: stress that forms when forces squeeze an the rock. Shearing: pushes mass of rock in 2 opposite direction.

15. Faults Surface where rocks break or slide past each other. Hanging wall: the wall you would han g from. Footwall: the wall you put your foot on.

16. Faults Normal Fault: Rocks are pulled apart; hanging wall moves down relative to the footwall.

17. Reverse Fault: rocks are pushed together by compression, hanging wall moves up relative to footwall

18. Faults Strike-slip Fault: rocks are moved horizontally by opposite directions.

19. Mountain Building Folded Mountains: form where continents have collided. Applachians: formed when North America and Africa collided. Hint: push on the edges of a piece of paper towards the center.

20. Mountain Building Fault-block mountains: form when tension from normal faults forces blocks of rock to move upward