EPS SCI 8 Study Guide - Midterm Guide: Continental Crust, Fault Scarp, Plate Tectonics
12 Dec 2017
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Document Summary
Proposed continental drift theory in 1912 based on these observations. Noticed matching coastlines on both sides of the pacific ocean. Found fossils of the same species in separate continents. Objected wegener"s theory arguing that the strength of the mantle was far greater than any conceivable driving force. Proposed that rocks flow because they are heated from below & cooled from above. (aka convection): flow driven by heat from below. Hotter material is less dense, cooler material is more dense. Liquid continually overturns (like a pot on a stove) Became independent supercontinents from the split of pangaea & opening of the tethy"s sea in the late. *about 550 myr ago these continents were joined together & situated near the south pole. Theory: continents collide, insulate mantle underneath, then separate as mantle gets hot & upwells. Oceanic crust: thin (~8km), made of basalt, more dense.
