GEL Week 2- Drifting continents (1)

What is continental drift?

The hypothesis that continents are mobile. Proposed by Alfred Wegener in 1915.

What did Wegener propose?

Wegener proposed a former supercontinent-Pangea

Why didn’t scientists believe Wegener’s idea?

Problem: Lack of mechanism for drift (couldn’t understand how it worked)

Continental fit (Wegener’s evidence)

Continents seemed to fit together. Wegener argued the fit was not coincidental

Glacial evidence

Ancient glacial deposits on 4 continents. Some are now near equator, so those continents must have been away from equator in the past

Paleoclimatic evidence

Wegener predicted past climate (paleoclimate); claimed that rocks types deposited at Pangea location were based on climate at the time

Fossil evidence

Identical fossils were found on currently separated land. These organisms couldn’t have crossed an ocean, as they were unable to swim

Geologic evidence

Geologic matches were found across the atlantic (same geologic structures. rock types, and ages)