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Published byDarrell Miles Modified over 9 years ago
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Plate Tectonics Theory of why and how plates move
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Pangaea
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http://www2.wwnorton.com/college/geo/eg eo/flash/2_1.swfhttp://www2.wwnorton.com/college/geo/eg eo/flash/2_1.swf
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I.Layers of the Earth A.Lithosphere: A combination of the earth’s crust and upper mantle 1. ~ 55 miles thick 2. Contains oceanic and continental crust
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a.Oceanic crust: portion of the crust that lies underneath the ocean, dense basaltic rock b. Continental crust: portion of the crust that makes up the continents, less dense granite
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B. Asthenosphere: Layer of earth beneath the lithosphere. 1. semi solid rock that is like silly putty 2. More dense than the lithosphere
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II.Types of plate boundaries A. Divergent boundary: two plates are moving away from each other
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B. Convergent Boundary: plates are moving towards each other
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1. 3 types of collisions at convergent boundary a. Oceanic crust vs. continental crust i. More dense crust goes underneath the less dense (subduction)
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ii. Continental crust vs. continental crust same density so they go up (mountain ranges)
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iii. Oceanic crust vs. oceanic crust Island arc forms
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deep ocean trench
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C. Transform Boundary: plates slip past each other
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III. Causes of plate movement A.Convection: less dense things rise while more dense things sink 1. As the magma rises at the Mid- Atlantic ridge and creates new oceanic crust, dense crust is being forced under continents at convergent boundaries
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B.Paleomagnetism on the Ocean Floor: Magnetic patterns on the ocean floor alternate as liquid rock solidifies and locks in the magnetic orientation of the earth.
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