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Tectonic Plates

Tectonic Plates

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Tectonic Plates

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  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