ERS120H5 Lecture 6: ERS Lecture 6
Document Summary
Mafic (rich in magnesium and iron (fe): ultramafic. Felsic rocks light in colour, mostly made up of feldspars and silicates. Mafic rocks darker in colour, mostly made up of magnesium and iron. Partial melting release of silicic components first as rock melts, separates mafic and felsic material, resulting in felsic magma and mafic residue. Fractional crystallization formation and settling of mafic minerals first as rock cools, original magma is mafic resulting in the remaining magma to be felsic. Volatiles are released from the crust at convergent plate boundaires/subduction. Heat transfer/contact melting occurs at divergent/convergent continental plates. Higher pressure increases melting temperature of rocks. Lower pressures reduce the melting temperatures of rocks. Density differences in heat-transfer melting causes the magma to cool in between the fault zone or sutre zone. Heat rising from magma melt the crust and causes a volcanic eruption called a rhyolitic melt. Basaltic magma rising to the crust causes a volcanic eruption called a basaltic melt.
