GEOL 101 Lecture Notes - Lecture 3: Magma Chamber, Intrusive Rock, Andesite
23 Dec 2015
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(cid:1) (cid:1: low silica, high mg and fe, two types of basaltic lava flows. Intermediate (andesitic: moderate silica, moderate mg and fe, lava flow. Felsic (silicic or rhylitic: high silica, low mg and fe, lava flows. Viscosity resistance to flow (below magma listed from low to high) Builds up right over the main vent, acts like a cork to the volcano. Craters (what forms at the top: bowl-shaped depression, formed as lava piles up around the vent, accentuated by summit collapse into conduit, super sized crater can end up being filled with water, example: crater lake in oregon. **types of volcanoes formed is determined by the type of (cid:1) (cid:1) magma that is fueling the volcano** Examples: crater lake, oregon and yellowstone national. Stratovolcanoes intermediate in size: felsic to intermediate magma, concave shape because we are dealing with an intermediate magma that erupts and starts to run down but does not spread out very far.
