EOSC 114 Lecture Notes - Lecture 5: Shield Volcano, Volcanism, Debris Flow
12 Sep 2016
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Document Summary
May erupt many times and stay active for 100,000 yrs. Mafic magma from a plume of hot mantle. Difference between volcanoes on oceanic island arc and hotspot look at the age. Form a chain of volcanoes parallel to plate motion. Only one volcano active at the end of the chain. Island arc and island chain from hot spot. Hot material that rises from core/mantle boundary (deep) Melting (magma) caused by lower pressure near surface. If continental crust intermediate to felsic magma. Lava erupts from fissure, runs down gentle slopes, cooling. Trail of progressively younger crust leading to the hotspot. Created from large, explosive eruptions of felsic pyroclastic material. Created when roof of the magma chamber collapses. Melting of mafic to felsic rock by rising mafic magma, depends on location of hot spot. Types of volcanoes: shield volcanoes mafic, non-explosive, stratovolcanoes- intermediate, felsic, mixed, explosive, caldera felsic, explosive, cinder cones mafic, explosive.
