EAR 105 Lecture Notes - Lecture 8: Mafic, Connate Fluids, Mass Wasting
24 Oct 2016
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Document Summary
Heat from below: heat from the geothermal gradient; rate at which temperature increases with increasing depth. Heat vs pressure: melting point of minerals generally increases with increasing pressure. Decompression melting occurs when pressure is released. We classify igneous rocks two ways: tecture (crystal size, mineral composition (relates to elemental composition) vs. Felsic (silicic) rocks = 65a% silica by weight, and contain light-colored minerals that are abundant in silica, aluminum, sodium, and potassium. Intermediate rocks = silica contents between those of mafic and felsic rocks: gray or salt and pepper; no pink or potassium. Mafic rocks = 50% silica by weight, contain dark-colored minerals that are abundant in iron, magnesium, and calcium. Breaking down rocks by weathering (chemical and physical weathering) Transport of weathered material (erosion, mass wasting, sedimentation) Precipitation of minerals from a water solution. Sand, formed from grains, erodes off the rock cliffs and collects on the beach.
