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Plate Tectonics and Earth’s Interior

Plate Tectonics and Earth’s Interior. Pangea. Distribution of Late Paleozoic Fossils. Conventional Wisdom: Animals Migrated Across Land Bridges. Late Paleozoic Glaciation. Distribution of Ancient Mountain Belts. Patterns Fit, But Is It Possible?.

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Plate Tectonics and Earth’s Interior

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  1. Plate Tectonicsand Earth’s Interior

  2. Pangea

  3. Distribution of Late Paleozoic Fossils

  4. Conventional Wisdom:Animals Migrated Across Land Bridges

  5. Late Paleozoic Glaciation

  6. Distribution of Ancient Mountain Belts

  7. Patterns Fit,But Is It Possible? • Tremendous amount of energy needed to move continents around the globe • Wegener proposed that centrifugal force on the spinning Earth pushed continents from the south pole to the equator • Modeling/simulation indicated that this would be insufficient • Wegener proposed that the moving continents plowed through the oceans like an icebreaker • Experiments indicated that oceanic rock is stronger than continental rock, and so oceans would have cut through the continents Continental Drift was a Model without a Mechanism!

  8. Bathymetry of the Ocean Floor

  9. Volcanoes of the World

  10. Volcanoes Correlate Globally with Deep Earthquakes

  11. Benioff Zone of Seismicity

  12. Plate Tectonic Model

  13. Tectonic Plates

  14. Seismic Waves

  15. Seismic Wave Velocities

  16. Seismic Wave Paths S-Waves P-Waves

  17. Layers Within Earth

  18. Convection Cells and Plate Movements

  19. Plate Tectonic Model

  20. Differentiation: Basalt • Partial melting of peridotite will form basaltic magma • Basaltic magmas are formed from melting mantle due to upwelling heat

  21. Differentiation: Andesite • Partial melting of basalt will form an andesitic or granitic magma • Andesitic magmas are formed from melting oceanic crust • Subducting plate releases water (a flux) into mantle • Magma pools under crust and partially melts the oceanic crust

  22. Differentiation: Granite • Partial melting of andesite will form granitic magma • Granitic magmas are formed from melting of continental crust • Subducting plate releases water (a flux) into mantle • Magma pools under crust and partially melts the continental crust

  23. Sources of Heat for Metamorphism • Heat from Earth’s interior • Geothermal gradient is the increase in temperature with depth • Typical continental geothermal gradient is 25-30°C/km • Volcanically active areas have geothermal gradients of 30-50°C/km • Oceanic trenches have geothermal gradients as low as5-10°C/km

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