EARTH 119 Chapter 4: Portrait of a Planet Chapter 4
27 Sep 2016
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Document Summary
Earth 119- chapter 4: the way the earth works: plate tectonics. Plate tectonics: the theory that the outer layer of the earth (the lithosphere) consists of separate plates that move with respect to one another. Lithosphere: the relatively rigid, nonflowable, outer 100- to 150-km-thick layer of the. Earth, constituting the crust and top part of the mantle. Asthenosphere: the layer of the mantle that lies between 100-150 km and 350 km deep, the asthenosphere is relatively soft and can flow when acted on by force. Lithosphere plates: one of about 20 distinct pieces of the relatively rigid lithosphere. Plate boundaries: the border between two adjacent lithosphere plates. Active continental margins: a continental margin that coincides with a plate boundary. Passive margins: a continental margin that is not a plate boundary. Continental shelf: a broad, shallowly submerged fringe of a continent; ocean-water depth over the continental shelf is generally less than 200 meters; the widest continental shelves occur over passive margins.
