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THE THEORY OF PLATE TECTONICS
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INTRODUCTION Tectonics- large scale deformational features of the crust Plate tectonics Earth’s outer shell divided into plates Plates move & change in size thru time
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INTRODUCTION Ideas Continental drift- Alfred Wegener
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Early Case for Continental Drift- Alfred Wegener (F. B. Taylor & H. H
Early Case for Continental Drift- Alfred Wegener (F.B. Taylor & H.H. Baker) Continental coastlines fit together 1620 Sir Francis Bacon: Africa and S. America Rocks & structures indicated that continents joined Pangea- supercontinent of the late Paleozoic Separated into Laurasia & Gondwanaland Fossil evidence- Glossopteris & Mesosaurus Late Paleozoic glaciation Skepticism about Continental Drift Problem of driving mechanism
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Continental Drift Alfred Wegener 1912 Pangaea (ALL EARTH) Evidence:
Continents FIT together like the pieces of a puzzle Fossils Rocks & structures Paleoclimate
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Continental Drift Alfred Wegener 1912 Pangaea (ALL EARTH) Evidence:
Continents FIT together like the pieces of a puzzle Fossils Rocks and structures Paleoclimate
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Continental Drift Alfred Wegener 1912 Pangaea (ALL EARTH) Evidence:
Continents FIT together like the pieces of a puzzle Fossils Rocks and structures Paleoclimate
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Evidence for Continental Drift- Revisited
Fitting continents at continental slope rather than shoreline- 1000m depth Refined matches of rocks between continents Isotopic ages support matches Glacial evidence Matches between Africa and South America are particularly convincing
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