Earth Sciences 1022A/B- Final Exam Guide - Comprehensive Notes for the exam ( 28 pages long!)
29 Mar 2018
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Document Summary
Hot spots: chain of volcanic islands and seamounts forms as a plate move over a magma plume in the mantle, age of sediment gets older farther from hot spots. Mountains rise above ocean because of isostasy. Oceanic crust is thicker and moves under continental crust and push up. Mantle plume rises, uplifts, and splits continental lithosphere to form rift valley with blocks dropped along normal faults, and volcanoes along valley sides. Sea water ows in between and sea basins develop. Rift widens, seawater invades, and a new ocean basin forms whose sides experience no seismic activity but gradually subside under weight of sediment load. As mountains grow, undergo isostatic adjustments to balance weight. Oceanic crust subducts under continental, forming accretionary wedge, continental volcanic arc, and. One oceanic crust is more dense than the other and subducts forming volcanic island arc andesitic to granitic plutons. Continental crust is so light that it cannot subduct. Ocean closes, subduction stops, high mountains form.
