ENVIRSC 1G03 Lecture Notes - Lecture 8: Stratovolcano, Hornblende, Pyroxene
12 Apr 2016
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Document Summary
Crater= small circular depression at volcano top. Caldera= >1km diameter crater (formed by explosion and collapse) Volcano= a vent in the surface of the earth through which magma, gases, and rock fragments (pyroclastics) erupt, usually conical in shape. Different sizes, rock types, explosiveness, plate tectonics settings. Shield volcanoes (in hawaii) best volcano to live near. Composite volcanoes- smaller and less wide than shield volcanoes, crazy and dangerously explosive. Classification of igneous rocks: texture & mineral content. Texture: fine or coarse depending on how quickly magma cooled. Mineral content: depends on the origin and chemical evolution of the magma. Classification of igneous rocks reflects the chemical and cooling history of the rocks. 6 minerals compose 95% of the igneous rocks. 3-4 of these minerals commonly present in each type of igneous rock igneous rock families named after their most common rock members. All have silicate tetrahedra as part of their structure.
