EOSC 314 Lecture Notes - Lecture 5: Paleomagnetism, Continental Drift, Continental Crust
6 Oct 2017
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Document Summary
Density of earth: ignious rocks, cooled from a magma, composed mostly of silicone and oxygen, oceanic crust, denser, forms at the surface (usually spreading centres, continental crust, less dense. Formed deep below the crust: the crust is thicker under the continent than the ocean, the land is floating on the rock beneath it. Continents: thick, less dense compared to oceanic crust, higher elevation above mantle, sinks to greater depth in the mantle. Ocean floor: thin, more dense compared to continental crust, low elevation above mantle, sinks to shallower depth in the mantle. Compensation depth: certain depth (located in the mantle) at which the total weight per unit area (density) is equal all around the earth, the mantle gets displaces (pushed out) is equal to has been put in. The earth is divided into plates: creates high earthquake activity. Pangaea: about 250 million years, last time with one single continent.
