GEOLOGY 105 Chapter 15: geology chapter 15 test 4
28 Jan 2019
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Document Summary
If surface of the lithosphere were completely smooth ocean water would surround the earth as a uniform 2. 5 km deep layer. Surface of lithosphere is not smooth instead it has a vertical relief of almost 20 km as measured from the deepest point in the ocean to highest point on land. Dry land has an average elevation of 0. 8 km above sea level and covers 29. 2% of the earth"s surface. Seafloor accounts for the remaining 70. 8% of earth"s surface has an average elevation of 3. 7 km below sea level. Oceanic lithosphere rests on the asthenosphere so that its surface is lower than the surface of continental lithosphere. Ocean basins include several bathymetric provinces distinguished from one another by water dept. Water dept over the continental shelf does not exceed 500 m. Broad continental shelves form along passive continental margins, which are margins that are not plate boundaries and thus lack the frequency of earthquakes.
