1. Continental Drift

2. Looking at your Pangaea Puzzles…
What did you discover?

3. 1700’s – geologists thought that the continents had always remained in the same place
Early 1900’s – Alfred Wegener (VAY guh nur) thought continents could have once been joined together as one landmass

4. Wegener hypothesized…
All continents were once joined together in a single landmass and have since drifted apart
This idea became know as continental drift

5. According to Wegener…
Continents drifted together to form Pangaea (the supercontinent)
Means “all lands”
Existed about 300 million years ago
Over 10’s of millions of years ago, Pangaea began to break apart
Continents slowly moved to positions they are today

6. Wegener gathered evidence…
From different areas in science to support his ideas
Land features
Fossils
Climate change

7. Evidence from Land Features…
Mountains of Africa & S. America lined up
European coal fields matched up with fields in N. America

8. Evidence from Fossils…
Fossil – any trace of an ancient organism that has been preserved in rock
Glossopteris (glaw SAHP tuh ris) found in rocks in Africa, S. America, Australia, India, & Antarctica
Mesosaurus & Lystrosaurus (fresh water reptiles) found on different continents

9. Evidence from Climate…
As continent moves toward equator, climate becomes warmer
As continent moves toward poles, climate becomes colder
Continents carry with it fossils and rocks formed at old location

10. Evidence from Climate cont…
Example…
Fossils of tropical plants found on island in Arctic Ocean
Deep scratches in rocks show glaciers covered S. Africa (too warm for this to happen today)

12. Wegener’s Hypothesis….
Wegener suggested continents plowed across ocean floors

13. Wegener could not provide a satisfactory explanation for the force that pushes or pulls the continents
Could not identify cause of continental drift so…