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Andesite - Wikipedia, the free encyclopedia
Andesite (pronounced /ˈændəsaɪt/) is an igneous, volcanic rock, of intermediate composition, with aphanitic to porphyritic texture. The mineral assembly is typically dominated ...
Andesite
Andesite from the Sutter Buttes, California. ... Andesite (c) 2007 Andrew Alden, licensed to About.com, Inc. (fair use policy)
Andesite line - Wikipedia, the free encyclopedia
The andesite line is the most significant regional geologic distinction in the Pacific Ocean basin. It separates the mafic basaltic volcanic rocks of the Central Pacific Basin from ...

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Andesite, a dark, fine-grained volcanic rock, the extrusive equivalent of diorite. Intermediate in composition between basalt and rhyolite, andesite consists mostly of plagioclase feldspar and lesser amounts of biotite or hornblende. The rock occurs as lava flows and dikes in regions where the plates of the earth's crust collide with one another—in the Aleutian islands, the Andes and Cascades mountains, Japan, and Siberia. In other areas of volcanic activity, basalt predominates. See also Plate Tectonics.