Geology Notes Feb 7 - conducted to the surface if the earth...

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Geology Notes Feb 7 -Classification of Igneous rocks: texture, mineral and chemical composition Magma -Molten Rock with dissolved gas: H20 + CO2 -Generated at depth -Eruption if magma reaches surface -Solidifies underground if doesn’t reach surface -intrudes country rock -intrusive contact -Felsic are rich in Silica and sodium and potassium content, low in iron, magnesium and calcium, has a lower melting point -Mafic- opposite of Felsic, and has a higher melting point -Magma is a partial melting of rock at depth -Source of heat is the geothermal gradient, rate of temperature increase with depth, average 30 C/km depth, not the same everywhere, and this all tells us that heat is being
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Unformatted text preview: conducted to the surface if the earth from the interior-melting points of minerals increase with pressure-water added under pressure lowers melting point of minerals-Magma differentiation –mirror image of partial melting-crystal formation over a range of temp, first to melt are first to crystallize-Fractional crystallization-as crystallization proceeds, crystals are separated from the melt, thus the melt evolves away from the compostion of the crystals removed-Dikes cut across layers of country rock-Sills are parallel to them-Batholiths are the largest forms of plutons-...
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This note was uploaded on 03/27/2008 for the course GEO 100 taught by Professor Demets during the Spring '08 term at University of Wisconsin Colleges Online.

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