GEOL-1010 Lecture Notes - Lecture 4: Continental Crust, Oceanic Crust, Andesite
5 Feb 2018
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Geology in the news: large diamonds from great depth are being studied for the first time, formed > 220 miles below earth"s surface, providing new insights into the composition. Why do we care: lava threatening to destroy homes, how can we minimize damage, we use a lot of these rocks in construction. What is magma: magma: molten rock, if you heat up the rock until it is completely melted. Sounds like lava, the only difference is where you find it: lava: magma that made it to the surface of the earth. Melting processes: how to melt rock, 1. Magma: rhyolite= another type of igneous rock, temperature, 700-800, coolest type of magma, silica content, about 70, depth, more shallow. In continental crust (not in mantle but in crust, specifically continental: water content, wet magma. Part two: igneous rocks: two broad types, 1. Plutonic (intrusive: form below the surface of the earth, 2. Volcanic (extrusive: form above the surface of the earth.
