EESA06H3 Lecture Notes - Basalt, Supercontinent Cycle, Mount John Laurie
8 May 2012
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Document Summary
Orogeny (mountain/formation) is an episode of mountain building, intense deformation of the rocks in a region. Arc-continent convergence: when an island arc collides with a continent it destroys oceans by subduction, flipping subduction zone - direction of the new subduction is opposite to the direction of the original subduction. Continent-continent convergence: mountain belts form when an ocean basin closes and continents collide, ex. Nothing is fixed in plate tectonics (boundaries, subduction, etc. ) Plate"s sizes can change (smaller, larger, etc. ) Movement of mantle rock beneath the plate. Mantle plumes narrow columns of hot mantle rock that rise through the mantle from thermal boundary layers at the base of the mantle. Continental breakup caused by mantle plume (diagram page 58) Plumes may form hot spots: yellowstone. Seamounts cone-shaped undersea mountains that rise 1,000m or more above sea floor (diagram. Guyots flat-topped seamounts found mostly in the western pacific ocean. Flat top is because of wave actions.
