11 ocean floor - Earth Sciences 1022a Lecture Brief 20 Sep...

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Earth Sciences 1022a Lecture Brief 20 Sep 09 THE OCEAN FLOOR Mapping the ocean floor is done by comparing multibeam sonar and satellite images Continental Margins : passive continental margins – not associated with plate boundaries, volcanoes, or earthquakes; three parts include: continental shelf: gentle slope from shoreline to 130 m depth, averages 80 km wide; valuable for oil and gas reserves, sand and gravel deposits, and fishing grounds - rivers cut into it during glaciations when sea level fell and mammals roamed on it continental slope: steeper slope beyond the shelf about 20 km wide that forms the boundary between continental crust and oceanic crust continental rise: gentle slope formed by turbidity currents and deep-sea fans submarine canyons and turbidity currents: valleys cut into the continental slope - some extend from river valleys carved during glaciations, others form by earthquake induced turbidity currents of dense sediment-rich water eroding the shelf and slope - turbidity currents form
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This note was uploaded on 02/27/2010 for the course EARTH SCIE 1028 taught by Professor Hicko during the Spring '10 term at UWO.

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