1. The Dynamic Earth

2. Do Now 3/28/12 Who was Alfred Wegener? What did he claim?
Do you believe him? Why or why not?

3. Theory of Continental Drift
The idea that all of the continents were once joined and are still drifting apart

4. Pangaea
The giant land mass that broke apart about 200 million years ago.

5. Pangaea
This idea was proposed by a German scientist named Alfred Wegener in 1912.

6. Evidence Supporting Continental Drift
1. Shape- continents fit together like a puzzle

7. Evidence Supporting Continental Drift
2. Fossil Evidence- similar species found on different continents

8. Wegener’s matching of fossils different continents

9. Evidence Supporting Continental Drift
3. Climate- evidence of glacial deposits in Africa and South America

11. Evidence Supporting Continental Drift
4. Rocks- age and types of rock match across continents

12. Evidence Supporting Continental Drift
5. Mountains- ranges match up across continents

13. Wegener’s matching of mountain ranges on different continents

14. Guess What…
People didn’t believe in Wegener’s theory because… he could not explain how or why the continents were moving!!!

15. But wait…
Seafloor spreading was detected using sonar during WWII that helped explain the how and why.

16. Seafloor Spreading