CAS ES 105 Lecture 5: Notes
7 Oct 2015
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Document Summary
Andesite and rhyolite volcanism: at subduction zones; derived from melting of subducted ocean crust (basalt) or overlying mantle wedge (wet peridotite) due to influx of volatiles (lots of gases, also continental hot spots , such as yellowstone, wy and. Mammoth, ca: high silica and low temperature high viscosity, highest volatiles (co2, h20, most explosive. Linear to arcuate chains of volcanic islands 100-200km above inclined subduction zone with a forearc accretionary wedge and trench and back arc basin. Andean margin accretion complex folded geocline lower crustal melting slab melting (adakites) Wedge metasomatism and wet pyrolite melting: like island arcs increased sources for melting, including the subducted basaltic ocean slab overlying mantle wedge and lower continental crust. Strata or composite volcano (mt fuji, japan: lower temperature (600-900c) and higher silica leading to. 10^5x more viscous high volatile contents causing dangerous & more explosive volcanoes. 87: deep earthquakes because the subducting slab is cold.
