Evidence of Plate Tectonic Processes

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Evidence of Plate Tectonic Processes

  1. 1. Plate Tectonic Processes d c e b a © 2011 Pearson Education, Inc.
  2. 2. Sea Floor Spreading Evidence Frederick Vine and Drummond Matthews (1963) Sea floor stripes record Earth’s magnetic polarity © 2011 Pearson Education, Inc.
  3. 3. Age of Ocean Floor Late 1960s deep-sea drilling. Radiometric dating of ocean rocks. Symmetric pattern of age distribution about mid-ocean ridges. Oldest ocean floor only 180 million years old. © 2011 Pearson Education, Inc.
  4. 4. Age of Ocean Floor © 2011 Pearson Education, Inc.
  5. 5. Earthquakes As Evidence Most large earthquakes occur at subduction zones. Earthquake activity mirrors tectonic plate boundaries. © 2011 Pearson Education, Inc.
  6. 6. Global Distribution of Earthquakes © 2011 Pearson Education, Inc.
  7. 7. Types of Plate Boundaries © 2011 Pearson Education, Inc.
  8. 8. Examples of Plate Boundaries © 2011 Pearson Education, Inc.
  9. 9. Transform Boundary Features Offsets oriented perpendicular to mid-ocean ridge ◦ Segments of plates slide past each other Offsetspermit mid-ocean ridge to move apart at different rates Shallow but strong earthquakes © 2011 Pearson Education, Inc.
  10. 10. Transform Boundary Features Oceanic Transform Fault – ocean floor only All transform faults occur between mid-ocean ridge segments. © 2011 Pearson Education, Inc.
  11. 11. Applications of Plate Tectonics Mantle Plumes and Hotspots ◦Intraplate features Volcanic islands within a plate Island chains Record ancient plate motions ◦Nematath – hotspot track © 2011 Pearson Education, Inc.
  12. 12. Global Hotspot Locations © 2011 Pearson Education, Inc.
  13. 13. Hawaiian Island – EmperorSeamount Nematath © 2011 Pearson Education, Inc.
  14. 14. Plate Tectonics and IntraplateFeatures Seamounts ◦ Rounded tops Tablemounts or guyots ◦ Flattened tops Subsidence of flanks of mid-ocean ridge Wave erosion may flatten seamount © 2011 Pearson Education, Inc.
  15. 15. Detecting Plate Motion withSatellites © 2011 Pearson Education, Inc.
  16. 16. Paleogeography Paleogeography – study of ancient continents Continental accretion ◦ Continental material added to edges of continents through plate motion © 2011 Pearson Education, Inc.
  17. 17. Paleogeographic Reconstructions © 2011 Pearson Education, Inc.
  18. 18. Future Predictions Future positions of continents and oceans ◦ Assume same direction and rate of plate motions as now. © 2011 Pearson Education, Inc.
  19. 19. World Map 50 million Years inFuture © 2011 Pearson Education, Inc.
  20. 20. Wilson cycle John Tuzo Wilson Life cycle of ocean basins ◦Formation ◦Growth ◦Destruction © 2011 Pearson Education, Inc.
  21. 21. Wilsoncycle © 2011 Pearson Education, Inc.

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