EPSC 201 Lecture Notes - Lecture 15: Pyrite, Goethite, Net.
11 Mar 2013
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Document Summary
Partial melting minerals that melt at low temperatures melt into a liquid before minerals with high melt- ing points. If the mantle is in the range where only some melting occurs, partial melting occurs. The minerals with lower mps melt and leave the mantle, forming a magma. The mineral that is last to melt is magnesium rich olivine. The iron olivine melts at a lower temperature. In general, minerals with high silica content melt lower (feldspar and quartz). The early magma is enriched in potassium, sodium, and silica, because these are found in minerals with low mps. The left over residue that doesn"t melt is called mafic residue and contains lots of magne- sium olivine. This chart shows which minerals melt the easiest. What we see is that as the silicates get more compli- cated, the temperature of crystalliza- tion increases (from tetrahedrons to silicate sheets). At the bottom, the minerals melt eas- ily, and have a low mp.
