Earth Sciences 1022A/B Lecture Notes - Lecture 11: Subduction, Abyssal Plain, Continental Crust
10 Jan 2017
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Document Summary
You can map the ocean floor by comparing multibeam sonar and satellite images. Multibeam sonar emits sound waves in fan shape beneath the ships haul, however the sonar doesn"t cover much area and can only collect data small parts at a time. Satellite images have detected the ocean floor isn"t flat and detects the structure of the oceans floor. Not associated with plate boundaries, volcanoes, or earthquakes. Contains three parts: continental shelf, continental slope, and continental rise. 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 glaciation when sea level fell and mammals roamed on it. Steeper slope beyond the shelf about 20 km wide that forms the boundary between continental crust and oceanic crust. Gentle slope formed by turbidity currents and deep sea fans.
