EASC 104 Lecture Notes - Volcanic Arc, Sulfur Dioxide, Continental Crust
28 Dec 2012
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Document Summary
Magma consists of liquid (melt), solid (crystals), and volatiles (gases that are typically dissolved in the melt of the magma, water carbon dioxide, sulfur dioxide) Viscosity: a liquid"s/fluid"s resistance to flow if the liquid has low viscosity, it will be able to flow easily. Stratavolcano: made up of layers (strata) island arc: ocean-ocean collision. Rhyolite (felsic): most silica, most explosive (explosivity), most gas (volatile), most viscosity. Basalt (mafic): lowest silica, least explosive (effusive), least gas (volatile), least viscosity. Pressure is also increasing as you go down=increasing melting temperature. Must reduce melting temperature or increase the heat. Water acts as a catalyst to induce melting for volatiles for rocks to melt faster. Most volcanoes happen around pacific ring of fire. Volcanoes in the middle of nowhere and not near plate boundary associated with plumes of heat in the mantle. Especially when these occur in oceanic plates, they form basaltic magma; melting mantle not the continental crust.
