Continental Drift Theory

1. Continental Drift Theory

4. What is Continental Drift Theory? Continental drift theory: Proposed by Alfred Wegener that all the continents were once together as one super continent named… Pangaea (1 Earth / Land) Continental drift theory

5. How long ago was Pangaea last together. Pangaea was last together 250 Million Years ago How did they break up? Wegener could never show how it broke up, he thought they floated apart on the ocean like boats on the water (they drifted with help from waves)

6. Proof or crazy idea?

7. What proof did he have? Proof: 1) Continents fit together like a puzzle Then when you line them up: 2) Mountains match up 3) Rock types match up 4) Plant fossils match up (Glossopteris) 5) Animal fossils match (Mesosaurus) 6) Glacial deposits match 7) Past climates match

8. Laurasia (Northern Half) Panthalassa Sea (1 large Ocean) Gondwanaland (Southern Half) Pangaea's first split was North and South (like the U.S.)

9. Purpose – Learn about Continental Drift Theory Data – Map of Pangaea (label its parts) 10 ?’s Con – What is CDT (continental drift theory)? Research Wegener (find new info). What were his proofs? What was Pangaea ? (give its parts: Northern, southern, large ocean) How long ago was it last together? What was Wegener missing? CDT lab

10. What happens if we plot earthquake locations

13. What did plotting Earth Quakes show? Plotting Earth quakes revealed the Earth was not 1 solid outer crust. It is made of plates. (Most appear at plate boundaries, so do volcanoes) What are plates? Plates are Large broken up pieces of the Earths crust (Lithosphere). ~ 8 major plates and several minor

14. How to find German U Boats?

15. Zebra banding: Iron acting as a compass in rock shows the North and South pole have been flipping. They also appear in a matching pattern on both sides of the Atlantic Other Discoveries

16. How else can you find a submarine

17. Using Sonar a Large Mt. Range is found to run down the center of the Atlantic. (Mid Atlantic Ridge) Rock close to the ridge (in the center of Atlantic) is newest. Far rocks (on both sides by the continents… S. America/Africa) are 250 million years old.

18. How can this be explained. Sea floor spreading: theory by Hess (A geologist in the Navy) that the Sea floor is young rock <250 million years old. Rock is getting created in the center at the Mid Atlantic Ridge and is being pushed outwards. This is growing the Atlantic Ocean. Sea floor spreading proves the plates are moving apart

20. Putting all this new information together? Plate tectonics is the movement of Earths Plates. And what happens at their boundaries. It is CDT + Plates + Sea Floor Spreading Plate Tectonics

21. http://www.youtube.com/watch?v=QDqskltCixA

22. How do plates move? Plates move due to convection currents in the mantle.

23. Why do Continents move? Continents move because they ride on top of the plates.

24. How do plates move?

25. What are the layers of the Earth called?

31. What are the layers of the Earth called?

32. Layers of the Earth. • 1) Core (center): 2 parts • A) Inner core (Solid Iron and Nickel) • B) Outer core (Liquid Iron and Nickel) • 2) Mantle: flowing molten (melted) rock • Convection currents move mantle around • Lava = molten rock on surface • Magma = molten rock under the surface

33. 2B) Asthenosphere – upper part of the mantle, called plastic mantle because it flows like heated plastic (continents ride on this) 3) Lithosphere – The crust & Rigid Mantle Ocean crust – Basalt (bass, salt) d= 3.0g/cm3 Continental crust – Granite (counter tops) d=2.7g/cm3 Ocean crust is more dense

35. What clues do we have about the inside of the Earth if we have never been down there? To infer about the interior of the Earth we use: 1) Meteorites: They have iron & nickel cores. If we started from the same materials we should have an iron and nickel core too. *Shows composition The Earths interior

36. 2) Earthquakes – Earthquakes send seismic waves through the Earth. Based on their actions, we can infer a solid and liquid core. *shows state of matter

37. 3) Lava. By studying lava you are studying material that was inside the Earth. *shows hot interior

38. How can plates move in relation to one another. Plates can move in 3 ways to each other 1) Divergent – divides or moves apart 2) Convergent – Comes together 3) Transform – Slide past each other Types of PLATE Boundaries

39. What are divergent boundaries? Divergent boundaries

46. What happens at a Divergent Boundary? At a divergent boundary: 1) Plates move apart 2) Plates grow (addition of Lava) 3) Ridges are pushed up 4) Rift valleys are created (Rift ~ Ripped) These occur on continents too

48. What happens when continental plates with the same Density crash? http://www.youtube.com/watch?v=loFxYSHxTf0&feature=related Convergent boundaries

49. When 2 continental plates with the same density converge they buckle up and make mountains like the Himalayas, (Everest is where India collided).

50. What happens when a Denser Oceanic plate converges with a less dense continental plate?