intro_to_geo_7

intro_to_geo_7 - Magma and igneous rocks Extent of igneous...

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Magma and igneous rocks Extent of igneous rocks Igneous rocks make up a majority of the crust Basalt/gabbro make up most of oceanic crust Granite and granodiorite make up most of continental crust Ultramafic and intrusive igneous rock peridotite makes up the mantle, including the rigid, subcrustal lithosphere Sources of heat Earth was initially so hot that its surface was molten; heat was attained from gravitational compression radioactive isotopes meteoric bombardment differentiation of Earth’s metallic core After sufficient time, the magma surface cooled to produce Earth’s first (igneous) rocks Igneous rocks solidify (freeze) from melt (either lava or magma) Melts are derived from: pressure release addition of volatiles the assimilation of heat from hot surrounding rocks or melts Freezing magma vs. freezing water Crystallization from magma is similar to freezing ice cubes in that crystals form from the liquid state upon passage of the liquid through a critical temperature (or
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This note was uploaded on 04/08/2011 for the course GEOL 2001 taught by Professor Babaie during the Winter '09 term at UGA.

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intro_to_geo_7 - Magma and igneous rocks Extent of igneous...

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