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Plate Tectonics

Plate Tectonics. The earth in motion. Earth’s Interior. Science of Geology Studying surface changes Constructive forces Build up mountains and land masses Destructive forces Wear away mountains and other surface features Wind, water, and waves Finding indirect evidence Seismic waves.

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Plate Tectonics

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  1. Plate Tectonics The earth in motion

  2. Earth’s Interior • Science of Geology • Studying surface changes • Constructive forces • Build up mountains and land masses • Destructive forces • Wear away mountains and other surface features • Wind, water, and waves • Finding indirect evidence • Seismic waves

  3. A Journey to the Center of the Earth • Temperature • Increases as you travel toward the core • Pressure • Increases as you travel toward the core

  4. Layers inside the earth Convection currents Crust Mantle Core

  5. Crust Mantle Core

  6. The Crust • Earth’s outer skin • Includes dry land and the ocean floor • 5 to 40 kilometers thick • Oceanic crust • Basalt • Continental crust • granite

  7. The Mantle • Solid layer of hot rock • 3,000 kilometers thick • Lithosphere • Rigid • Upper part of mantle and all of crust • Floats on top of astheosphere • 100 kilometers thick • Asthenosphere • Bends like plastic • Soft • Can flow slowly

  8. The Core • Core • 30% of earth’s mass, 15% of volume • Slightly smaller than the moon • Outer core • Liquid • Behaves like a thick liquid • Iron and nickel • Inner core • Solid • Extreme pressures • Iron and nickel

  9. Convection Currents and the Mantle • Heat Transfer • Radiation • Direct Transfer of energy through empty space • Conduction • Heat transfer by direct contact • Convection • Heat transfer by the movement of a heated fluid

  10. Drifting Continents • Continental Drift • Alfred Wegener • Pangaea – 300 million years ago

  11. Pangaea • Evidence • From landforms – matching mountain ranges • From fossils – Glossopteris found in Africa, S. America, Australia, India, and Antarctica • From climate – warm area fossils found where it is cold now

  12. Sea-Floor Spreading • Mid-Ocean Ridge • Longest mountain chain on ocean floor • Iceland • Sonar used to map the ocean floor

  13. Evidence of Sea-Floor Spreading • Molten material • Pillows of hardened magma • Magnetic stripes • Earth’s magnetic poles have reversed themselves • Drilling samples • Older rocks are further away from the ridge • Younger rocks are closer to the ridge

  14. Mid-Ocean Ridge

  15. Sea-floor spreading

  16. Theory of Plate Tectonics • Theory of plate motion • Pieces of earth’s crust in constant motion • Driven by convection currents • Explains the formation, movement and subduction of crust • Plate boundaries • Transform boundaries • Divergent boundaries • Convergent boundaries

  17. Plate boundaries

  18. Volcano Review #1 #2

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