Magma and volcanoes

Magma and volcanoes - Geol 101 Magma and Volcanoes...

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Geol 101 Magma and Volcanoes 04/10/2007 12:42:00 In the news: Mt. Saint Helens October 1, 2004.  A small explosive eruption of Mt. Saint Helens following a  week of earthquake activity September 23, 2004. Earthquakes began  Bowen’s Reaction series predicts: Mineral Structure Temperature of igneous rock formations Mineral and chemical composition Viscosity  The ability to flow Forms thick, dome like blob Depends on o Temp and SiO2 o Granitic magmas much more viscous than basaltic Granitic Magmas (Si-rich) commonly form intrusive rocks Basaltic magmas (Si-poor) extrusive Nonviscous Spreads out in a thin sheet Pluton Bodies of intrusive igneous rocks, all shapes/sizes Minor
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Dike Sill (flat like a window sill) Laccolith (like a sill just with a dome shape in the middle) Volcanic Pipe Batholith Largest, irregular shape o 1000s km long Xenoliths Rock body enclosed in magma Stoping o Rising magma dislodges rock Basaltic Flow Low Si Shield Volcano Lava flows downward Andesitic Flow Intermediate Si Composite Volcano Dome so the lava flows both directions Rhyolitic Dome/Spire High Si
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Domes and Spires Basaltic Magam
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This note was uploaded on 04/28/2008 for the course GEOL 101 taught by Professor Olinsky during the Fall '08 term at Texas A&M.

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Magma and volcanoes - Geol 101 Magma and Volcanoes...

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