Theory of PlateTectonics – an  overview    Geo 100N   Spring 2005
Plate Tectonics -Overview1.   The Lithosphere and Crust2.   Basic Concepts of Plate Tectonics3.   Plate Movements and Boun...
Inside the Earth                   USGS
The Lithospherehttp://volcano.und.edu/vwdocs/vwlessons/plate_tectonics/part1.html
Basic Concepts of Plate       Tectonics
The Earth’s surface is covered by  about 12 lithospheric plates                             USGS
The plates move slowly (a few          cm/year).                           USGS
Most endogenic geological activityoccurs at or near plate boundaries.                      Endogenic = process that origin...
Plate interiors are relatively quiet            geologically
Plate Movements and     Boundaries
Divergent boundariesPlates move apartVolcanic activity is always presentEarthquakes are shallowTwo types of boundaries:  1...
Oceanic Divergent Boundary   Sea-floor spreading of oceanic lithosphere   examples: Mid Atlantic Ridge, East Pacific    ...
Sea-floor spreading of oceanic          lithosphere                   USGS, Digital elevation model
Mid Atlantic Rift at Iceland               Þingvellir (Thingvellir), Iceland
Continental Divergent BoundaryContinental riftingEventually, oceanic crust is formed and  divergence becomes oceanic typeM...
East African Rift ZoneOldoinyo Lengai, Kenya
Convergent boundariesPlates move toward each otherVolcanic activity commonDeep, medium, and shallow   earthquakesThree typ...
Ocean-ocean convergence   Subduction – one oceanic plate subducts    (dives) beneath the other   Volcanic island arc is ...
Aleutian Islands, Alaska              Kanaga
Ocean-continent convergenceDuring ocean-continent convergence,  oceanic lithosphere always subducts  beneath continental l...
Continent-continent convergenceSubduction does not occur (continental crust  is too buoyant to be subducted)Mountain build...
India-Asia Collision   Collision of India    with Eurasian plate    caused uplift of the    Himalaya, the    highest moun...
Transform boundaries          Plates slide past each            other          Little or no volcanic            activity  ...
San Andreas Fault         Pacific plate is           moving NW relative           to the North           American Plate   ...
Summary1.   Earth’s surface is covered by about     12 lithospheric plates.2.   The plates move slowly (2.5-15     cm/year...
Geo 100- Useful InformationCourse Homepage:  http://mercury.atmos.albany.edu/geo10For SKN, email your name to  instructor ...
04.plate tectonics
04.plate tectonics
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04.plate tectonics

  1. 1. Theory of PlateTectonics – an overview Geo 100N Spring 2005
  2. 2. Plate Tectonics -Overview1. The Lithosphere and Crust2. Basic Concepts of Plate Tectonics3. Plate Movements and Boundaries4. Summary
  3. 3. Inside the Earth USGS
  4. 4. The Lithospherehttp://volcano.und.edu/vwdocs/vwlessons/plate_tectonics/part1.html
  5. 5. Basic Concepts of Plate Tectonics
  6. 6. The Earth’s surface is covered by about 12 lithospheric plates USGS
  7. 7. The plates move slowly (a few cm/year). USGS
  8. 8. Most endogenic geological activityoccurs at or near plate boundaries. Endogenic = process that originates within the Earth’s interior Mt St Helens, 1980
  9. 9. Plate interiors are relatively quiet geologically
  10. 10. Plate Movements and Boundaries
  11. 11. Divergent boundariesPlates move apartVolcanic activity is always presentEarthquakes are shallowTwo types of boundaries: 1. Oceanic 2. Continental
  12. 12. Oceanic Divergent Boundary Sea-floor spreading of oceanic lithosphere examples: Mid Atlantic Ridge, East Pacific Ridge USGS
  13. 13. Sea-floor spreading of oceanic lithosphere USGS, Digital elevation model
  14. 14. Mid Atlantic Rift at Iceland Þingvellir (Thingvellir), Iceland
  15. 15. Continental Divergent BoundaryContinental riftingEventually, oceanic crust is formed and divergence becomes oceanic typeModern Example: East Africa
  16. 16. East African Rift ZoneOldoinyo Lengai, Kenya
  17. 17. Convergent boundariesPlates move toward each otherVolcanic activity commonDeep, medium, and shallow earthquakesThree types of Convergent Boundaries 1. Ocean-ocean 2. Ocean-continent 3. Continent-continent
  18. 18. Ocean-ocean convergence Subduction – one oceanic plate subducts (dives) beneath the other Volcanic island arc is formed Example: Aleutian Islands
  19. 19. Aleutian Islands, Alaska Kanaga
  20. 20. Ocean-continent convergenceDuring ocean-continent convergence, oceanic lithosphere always subducts beneath continental lithosphereContinental volcanic arc formedExample: Andes mountains
  21. 21. Continent-continent convergenceSubduction does not occur (continental crust is too buoyant to be subducted)Mountain building occurs without volcanismExample: Himalayas, Alps
  22. 22. India-Asia Collision Collision of India with Eurasian plate caused uplift of the Himalaya, the highest mountains on Earth.
  23. 23. Transform boundaries Plates slide past each other Little or no volcanic activity Shallow earthquakes Example: oceanic transform faults; San Andreas Fault
  24. 24. San Andreas Fault Pacific plate is moving NW relative to the North American Plate As plates move, transform fault slips, and earthquakes occur
  25. 25. Summary1. Earth’s surface is covered by about 12 lithospheric plates.2. The plates move slowly (2.5-15 cm/year).3. Most volcanism and earthquake activity occurs at or near plate boundaries.4. Plate interiors are relatively quiet geologically (some exceptions).
  26. 26. Geo 100- Useful InformationCourse Homepage: http://mercury.atmos.albany.edu/geo10For SKN, email your name to instructor atarnason@albany.edu

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