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Continental Drift

Continental Drift. Alfred Wegener (1912) First serious proponent Took time to look carefully at the data & carefully study it Many scientists have ideas and don't follow up Many geologists were more familiar with the data, but couldn't bring themselves to believe it

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Continental Drift

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  1. Continental Drift Alfred Wegener (1912) • First serious proponent • Took time to look carefully at the data & carefully study it • Many scientists have ideas and don't follow up • Many geologists were more familiar with the data, but couldn't bring themselves to believe it • Wegener looked at the facts in the perspective of the theory & looked for consistencies Alfred manning the weather station, Greenland - 1913

  2. Fit of the Continents A modern view than Wegener’s uses 1000 or 2000 m isobath as estimate of edge of continental crust

  3. Fit of Structural Elements

  4. Pennsylvanian (300 Ma) Glaciation Glacial striations in bedrock, South Australia

  5. Pennsylvanian (300 Ma) Glaciation Arrows indicate ice movement directions Using present continental locations

  6. Pennsylvanian (300 Ma) Glaciation Arrows indicate ice movement directions Using pre-drift continental locations

  7. Fossil Evidence Glossopteris: an ancient seed fern (200 Ma) Distribution of Glossopteris fossils

  8. Fossil Evidence Distribution of Mesosaurus fossils Mesosaurus couldn’t swim in open ocean

  9. Paleomagnetism The Earth as a dipole Magnetic declination and inclination

  10. Paleomagnetism Magnetization of volcanic rocks and sediments

  11. Paleomagnetism “Polar Wandering” curves

  12. In spite of this data, the theory of continental drift died off in the 1950s, mainly because the geophysicists could not find an adequate mechanism to move the rigid crust and mantle

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