1. Plate Tectonics

2. Plate Tectonics is a theory that describes the formation, movements, and interactions of Earth’s plates.

3. Alfred Wegener, a German meteorologist, proposed a hypothesis called Continental Drift in 1912.

4. Continental Drift supposed that the continents have moved, or drifted, from one location to another over long periods of time.

5. moved, or driftedmoved, or drifted

6. Wegener based his idea on the following observations: Wegener based his idea on the following observations:

7. The continents had similar shapes.

8. The same fossils were found in South America and Africa.

9. Similar rock formations were found in South America and Africa.

10. Climate Change: Areas once covered in glaciers are now in warmer climate zones.

11. Wegener’s idea could not explain how the continents moved.

12. The Theory of Plate Tectonics suggests that the continents are part of the lithospheric plates. Evidence for this:

13. Volcano, Earthquake, and Mountain Belts are located along plate boundaries.plate boundaries

14. The ocean floor gets older away from a mid-ocean ridge. away

15. The rock record shows that the magnetic field of the Earth has reversed many times.magnetic field

16. Types of Plate Boundaries

17. Divergent Boundary Rift Valleys and Mid- Ocean Ridges

18. Convergent Boundary Deep Sea Trenches, Subduction Zones, and Mountain Ranges

19. Convergent (2 Types)

20. Convergent Subduction More Dense (Oceanic Crust) Less Dense (Continental or Oceanic Crust)

21. Convergent Collision Equal Density Continental Crust

22. Transform (Strike-Slip) Boundary San Andreas Fault Division between North American and Pacific Plates

23. North American Plate Pacific Plate North American Plate

24. Types of Plate Boundaries

25. Causes of Plate Movement

26. 3 Hypotheses Mantle Convection Ridge Push Slab Pull

27. Mantle ConvectionMantle Convection: The mantle moves the plates along as it convects (heats from below). Mantle Convection Animation #2 Mantle Convection Animation #2 Mantle ConvectionMantle Convection Animation #2

28. Ridge PushRidge Push: The accumulating magma at a mid-ocean ridge “pushes” material away. Ridge Push

29. Slab PullSlab Pull: When a plate subducts, it pulls the rest of the plate with it. Slab Pull