GEOS126 Lecture 2: Plate Tectonics and Ocean Basins Part 1
28 Nov 2018
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Document Summary
11km below sea level mariana trench to. 70% of the earth"s surface is covered by oceans. The earth"s surface is unique as it is bimodal (has two distinct peaks) 2/3 of the earth"s crust is less than. 200 m years old (young compared to the earth"s age of 4. 5 b years old) Can be divided into: oceanic crust. Isostasy: the crust floats on top because it is less dense than the fluid mantle. Oceanic crust is thinner and denser thus it sits lower on the mantle. As you go deeper into the earth, the. Core is made of mostly iron (around 95%) Ring of fire: 75% of the wold"s volcanoes and 90% of the earthquakes. Follows the plate boundaries that encircle the pacific. Different combinations of the three are possible such as weak convergent which would include transform or side to side motions.
