GEOL 212 Lecture Notes - Lecture 52: Outer Core, Volatiles, Convection
26 Dec 2017
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Document Summary
Igneous rocks: rocks that form through the solidification of magma. Volcanism: the eruption of magma onto a planet"s surface. The geotherm - a graph of the relationship of temperature and depth, is a useful means of visualizing the processes the cause rocks to melt. At right, a schematic geotherm tracks the big patterns of. Earth"s temperature gradient all the way to its center. The following graphs track: the terrestrial geotherm only to the depths of the asthenosphere (right), the melting curve for peridotite (below). The melting curve shows the boundary of temperature and pressure beyond which peridotite melts. Three factors influence melting point: temperature, pressure, volatiles. All other things being equal, every mineral has a distinct melting point. In the mantle, heat is brought upward by convection. As hot rocks convect upward they transfer heat to cooler rocks lying above them, which may melt. When rocks experience decompression without losing their heat, they can experience decompression melting.
