Continental drift theory
- Created by: bethanymcguire
- Created on: 15-05-17 18:59
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- Continental Drift Theory
- 1912 Alfred Wegner
- Pangea, before splitting into Laurasia and Gondwanaland... evidence based on:
- Jigsaw fit of South America and Asia
- Matching rock sequences link NW Scotland and E Canada
- Coal found in the Antartic
- Permian fossil brachiopods in India match those in Australia
- Mesosaurus found only in Brazil and SW Africa, aswell as glacial deposits in these 2 areas
- Pangea, before splitting into Laurasia and Gondwanaland... evidence based on:
- Criticisms and later evidence
- did not explain how they moved at the time
- 1919 convection currents
- 1946 sonar mapping of the ocean floor
- 1960 Hess/Dietz sea floor spreading
- 1963 paleomagnetism
- Paleomagnetism
- iron oxide once cooled and solidified, aligns with the polarity. records the magnetic orientation.
- magnetic fields measured by magnetometers which show a pattern of switches as it moves away from the mid atlantic ridge.
- oldest the further away you get from the MAR showing repeated reversals, confirming the spreading of the MAR
- Paleomagnetism
- 1912 Alfred Wegner
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