Earth Sciences 1022A/B Chapter Notes - Chapter 3: Magma Chamber, Phanerite, Aphanite
15 Nov 2018
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Document Summary
A magma"s composition is affected by the amount of silica, and the relative amounts of iron, magnesium, sodium, and calcium. Where the magma originate also controls the magma"s composition. As temperature changes and crystallization of minerals occur the magma composition will change. Previously formed crystals are removed from the melt to prevent them from reacting with the rest of the melt. Density, gravity contrasts causing the crystals to settle out of the. Hot magma absorbs and melts the rocks surrounding the magma chamber. Usually occurs when hot magma rises up through colder crustal/country rocks. Two or more melts combine to form a hybrid melt that in intermediate in composition. This is less common than fractional crystallization and assimilation. The bowen"s reaction series is a chart that gives the order of crystal formation as magma cools. Magma composition and temperature determines which parts of the sequence the melt will progress through. Different melts give rise to different volcanoes.
