GEOL107 Study Guide - Midterm Guide: Abyssal Plain, Convergent Boundary, Continental Crust
10 Dec 2016
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Document Summary
Mid-ocean ridges - the place where new crust is created. Plates moving apart from each other create a gap in which magma rises to fill it. About 70% of earth"s volcanic activity happens here. Abyssal hills- the crust moving away from the mid-ocean ridge. As it gets farther it cools and becomes more dense then sinks. They are the flattest portion of the ocean floor (very little relief). Deep ocean trenches- occurs at convergent plate boundaries where oceanic lithosphere is being subducted. They are long, linear, and the deepest depths of the ocean. Seamounts- underwater volcanoes (can be in a chain or individual) Guyots- flat-topped seamounts (due to erosion from waves). This indicates that at some point the seamount was at surface level. Continental margins- transition zone between land and ocean. Continental shelf- extends from shoreline to water depths of 100-300m, gentle slope, exposed during glacial time periods.
