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Plate tectonics:

Plate tectonics:. The Key to understanding mountain formation. Plate boundaries. ......DocumentsCLASSESMtn_geog10Videosess01_int_boundariesess05_int_boundaries.html. Volcanoes, earthquakes. ......DocumentsCLASSESMtn_geog10Videosess02_int_tectonicess05_int_tectonic.html.

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Plate tectonics:

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  1. Plate tectonics: The Key to understanding mountain formation

  2. Plate boundaries • ..\..\..\Documents\CLASSES\Mtn_geog\10\Videos\ess01_int_boundaries\ess05_int_boundaries.html

  3. Volcanoes, earthquakes • ..\..\..\Documents\CLASSES\Mtn_geog\10\Videos\ess02_int_tectonic\ess05_int_tectonic.html

  4. World’s tectonic plates

  5. Earth’s Topographic Regions Clue #1: Mountain ranges found only in certain areas (edges of continents)

  6. Marine fossils on top of Everest • Granite core • sedimentary • rock layer • Limestone • (top) Clue #2: Material composition of mountains N side, view from Rongbuk Monastery, Tibet

  7. Clue #3: Continental Shields in interior of continents

  8. GEOLOGY OF THE USA • Craton (kratos; • Greek for strength) • old and stable part of the • continental crust that has • survived the merging and • splitting of continents • interiors of continents • formed of a crust of • lightweight rock, e.g. granite, • attached to a section • of the upper mantle.

  9. Clue #4: Ocean crust oldest near continents and youngest towards middle of oceans oldest youngest

  10. Plate motion • Plates move away from, toward, or slide past each other. • There are 3 types of plate boundaries: - divergent - convergent - transform.

  11. Three types of plate boundary

  12. A. DIVERGENT PLATE BOUNDARY • occur along spreading centers where plates are moving apart • new crust is created by magma pushing up from the mantle

  13. Example: Mid-Atlantic Ridge • a topographically high area • near the middle of the Atlantic • Ocean • splits nearly the entire • Atlantic Ocean north to south,

  14. Divergent: Atlantic Ridge LAVA FOUNTAINS KRAFLA VOLCANO ICELAND

  15. B. CONVERGENT PLATE BOUNDARY • Plates are moving toward each other • destruction (recycling) of crust takes place along convergent boundaries Sometimes, pne plate sinks (is subducted) - SUBDUCTION ZONE

  16. Convergent plate boundaries 3 types depending on type of plate involved: • Oceanic-continental convergence • Oceanic-oceanic convergence • Continental-continental convergence

  17. 1. Oceanic-Continental Collision • oceanic Nazca Plate is pushing into and being subducted • under the continental part of the South American Plate • South American Plate is being lifted up, creating the Andes • Strong, destructive earthquakes • rapid uplift of mountain ranges are common in this region.

  18. Oceanic-continental: Pacific RING OF FIRE

  19. Example: Andes Mtns • West margin of the South American continent • oceanicNazca Plate is pushed toward and beneath the continental portion of the • South American Plate • typical example of a convergent plate boundary

  20. ALPAMAYO, CORDILLERA BLANCA

  21. 2. Oceanic-oceanic Collision • Subduction processes in oceanic-oceanic • plate convergence result in the • formation of volcanic arc islands

  22. Examples of volcanic arc islands • Aleutians • the Kuriles • Japan • the Ryukyus, • the Philippines • Indonesia

  23. 3. Continental-continental Collision • neither plate subducted because • the continental rocks are relatively light • like two colliding icebergs, plates resist • downward motion

  24. HIMALAYAS collision between the Indian and Eurasian plates has pushed up the Himalayas and the Tibetan Plateau

  25. C. TRANSFORM BOUNDARY • At a transform plate boundary, plates slide past each other. • Crust neither produced nor destroyed

  26. Example: San Andreas fault in California Pacific Plate slides past the North American Plate.

  27. Special case: HOTSPOTS “Plume” = huge column of upwelling lava

  28. HOTSPOTS HAWAII VIDEO http://www.teachersdomain.org/resource/ess05.sci.ess.earthsys.hawaii/

  29. How fast are plates moving? • The Arctic Ridge • slowest rate (less than 2.5 cm/yr) • East Pacific Rise near Easter Island, in the South Pacific about 3,400 km west of Chile • fastest rate (more than 15 cm/yr).

  30. Plate Motion Summary

  31. Mountain Maker, Earth shaker • Interactive media

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