J-i-T igneous rocks - Magma is molten rock that flows over...

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Magma is molten rock that flows over Earth's surface. True False Match the four magma compositions with their chemcial properties. lowest silica content, highest Fe-Mg content Forms andesites and diorites Forms peridotites Highest silica content, lowest Fe-Mg content lowest viscosity Forms granites and rhyolites Highest gas content medium silica content, medium Fe-Mg content Forms basalts and gabbros low silica content, high Fe-Mg content 1 .Felsic 2 . Intermediate 3 .Mafic 4 . Ultramafic Match the following terms, cooling rates, and likely geologic environments with the grain sizes observed in igneous rocks. cooled slowly aphanitic phaneritic cooled quickly magma chamber cools to form a pluton partially crystallized magma erupts from a volcano cooled slowly, then quickly porphyritic lava cools on the Earth's surface 1 . small crystals difficult to see with the naked eye 2 . large crystals easy to see without magnification 3 . mixture of small and large grains
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Why does peridotite melt at a divergent plate boundary? Pressure decreases as rocks rise through the mantle.
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This note was uploaded on 09/26/2011 for the course GEOL 1114 taught by Professor Staff during the Fall '11 term at The University of Oklahoma.

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J-i-T igneous rocks - Magma is molten rock that flows over...

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