1. 9.1 Continental Drift

2. Wegener’s hypothesis Alfred Wegener was a German scientist
Proposed his hypothesis of continental drift that stated, that the continents had once been joined to form a single supercontinent called Pangaea (1915)
Pangaea means all land
Wegener also hypothesized that around 200 million years ago Pangaea begin to break into smaller continents and drifted to their current positions today

4. Evidence
Similarity between the shorelines on the opposite sides of the coast
Fossil evidence for continental drift includes several fossil organisms found on different landmasses
Wegener argued that the organisms couldn’t cross the present day ocean
Land bridges were a thought, but if that were the case the fossils would still be on the sea floor

6. Evidence continued…
Rock evidence for continental drift exists in the way of several mountain belts that end at one shoreline, that then reappears on a landmass across the ocean
If Pangaea occurred then matching rock types and mountain belts should be seen in both present day landmasses
Like a puzzle

7. New theory…PLATE TECTONICS
New data on earthquakes and the Earth’s magnetic field led to new beliefs
1968 Plate Tectonics
Provides outline for understanding most geological processes. (example – mountain formation)