1. Tectonic Plates

2. Predict the layers: • Corn syrup • Water • Oil

3. Layers of Earth • picture

4. 2 Kinds of Crust • picture

5. 2 Kinds of Crust • Continental – less dense, thicker • Oceanic – more dense, thinner

6. 2 Kinds of Mantle • Upper – solid, floats on… • Lower – plastic (somewhat fluid) • Why?

7. Earth’s crust and upper mantle “float” on the plastic portion of the mantle.

8. Convection Currents • Movement of hot liquid or gas • Heated – rises • Cools – drops

9. Earth’s Crust Cracks… • Convection currents in mantle cause cracking in crust

10. Crustal Plates • Huge sections of earth’s crust that move relative to each other

11. What happens when they hit each other?

12. Types of Plate Boundaries • Divergent • Convergent

13. Divergent Boundary • picture

14. Convergent Boundary • picture

15. What happens when…

16. Divergent Boundary • picture

17. Divergent O to O • New crust formed and pushed up (ridge) • Ex. Mid-Atlantic Ridge

18. Ocean Ridges

19. Divergent C to C • Continent spreads, ocean basin may form • Ex. Red Sea

20. Red Sea

21. Convergent Boundary • picture

22. Ocean to Continent • Ocean plate goes below continent • Subduction • Subducted plate partially melts • Trenches, volcanic mountains • Ex. Western South America

23. O to C Convergent

24. O to O Convergent • Older slips below newer • Subducted plate melts • Volcanic islands formed • Ex. Aleutian islands, Japan

25. Aleutian Islands

26. Islands of Japan

27. C to C Convergent • Same densities, no subduction • Compression, folding, uplifting • Ex. Himalayas, Alps

28. Alps

29. Another type of plate movement…

30. Transform faulting • Plates move past each other

31. Ex. – Transform Faulting San Andreas Fault

32. How do you think scientists identified the plate boundaries?

33. What is the “Ring of Fire?”

34. Ring of Fire • picture

35. Activity #3 – Crustal Plates • “Connect the dots” – volcanoes and earthquakes • Label 8 major plates

36. Plate Map

37. Pangea Theory

38. Pangea Theory • 1912 – Alfred Wegener • Idea that continents were once part of one large land mass – theory of continental drift

39. How did he know? • Continents’ shapes fit together like a puzzle • Rocks and fossils found on different continents matched

40. Early 1960s • Scientific evidence proves continental drift, plate tectonics, and Pangea theory

41. Ocean Features Picture

42. Ocean Features Picture 2