Earth and Space Science / Unit 3: Plate Tectonics
3.3 Continental Drift
Notes
In 1912 Alfred Wegener proposed that continents once formed one supercontinent, Pangaea, and have drifted apart.
- Evidence: coastlines that fit (especially South America and Africa); matching fossils (Mesosaurus, Glossopteris) across oceans; matching rock types and mountain chains; glacial deposits in now-warm places.
- Wegener could not explain how continents move, so most scientists rejected the idea at first.
- Later evidence from the seafloor led to the accepted theory of plate tectonics.
Practice
Which was part of Wegener's evidence?
Matching fossils on separated continents suggested they were once joined.
The supercontinent in Wegener's hypothesis was called:
Pangaea means "all land".
Why was Wegener's hypothesis rejected at first?
Lack of a mechanism was the main objection.
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