1. CONTINENTAL DRIFT AND PLATE TECTONICS

2. DEFINE-CHAPTER 9 Continental drift subduction Trenches Plates

3. ALFRED WEGENER-1915 Proposed theory of continental drift Continents were once joined as Pangaea 200 mya

4. WHY WOULD HE THINK THIS?

5. THEORIES ARE BASED ON EVIDENCE Matching coastlines Matching fossils Matching rock types Ancient climates

7. MESOSAURUS

8. MATCHING ROCKS

9. MATCHING GLACIERS

10. IF THERE WAS SO MUCH EVIDENCE, WHY WAS THIS THEORY REJECTED? Answer on boards please with your partner. https://www.youtube.com/watch?v=T1-cES1Ekto

11. SEA FLOOR SPREADING The advent of sonar allows underwater topography to be viewed.

12. SEA FLOOR SPREADING This is the mechanism that moves the plates around. New ocean floor is produced at mid ocean ridges and consumed at trenches.

13. WHAT KINDS OF EVIDENCE WOULD SUPPORT THIS IDEA? Answer with your partner

14. MAGNETIC SYMMETRY HOW DOES THIS SUPPORT SFS?

15. SEDIMENT THICKNESS- HOW DOES THIS SUPPORT SFS?

16. AGE OF THE SEA FLOOR- HOW DOES THIS SUPPORT SFS?

17. CONCLUSION Earth’s lithosphere is divided into major plates which move around by the process of sea floor spreading. Alfred Wegner proposed continental drift which was falsified and turned into the theory of sfs. SFS leads to the theory of plate tectonics which we will learn about next.