A grey to grey-green colored volcanic rock containing 53% to 63% silica (compositionally between basalt and dacite). Minerals commonly found in andesite include intermediate composition plagioclase and hornblende.
Andesite is a gray to black volcanic rock with between about 52 and 63 weight percent silica (SiO2). Andesites contain crystals composed primarily of plagioclase feldspar and one or more of the minerals pyroxene (clinopyroxene and orthopyroxene) and lesser amounts of hornblende. At the lower end of the silica range, andesite lava may also contain olivine. Andesite magma commonly erupts from stratovolcanoes as thick lava flows, some reaching several km in length. Andesite magma can also generate strong explosive eruptions to form pyroclastic flows and surges and enormous eruption columns. Andesites erupt at temperatures between 900 and 1100° C.
Close view of andesite lava flow Brokeoff Volcano, California
Did you know?
The word andesite is derived from the Andes Mountains, located along the western edge of South America, where andesite rock is common.
Andesite was the main rock type erupted during the great Krakatau eruption of 1883.

Glossary of volcanic terms. - University of Wisconsin Oshkosh. . 2001.

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Look at other dictionaries:

  • Andesite — Andésite Un échantillon d andésite (en noir) avec des inclusions de zéolite …   Wikipédia en Français

  • andésite — [ ɑ̃dezit ] n. f. • 1866; d ab. en all., pour désigner une lave des Andes; de Andes ♦ Minér. Variété de feldspath à sodium et calcium. ⇒ plagioclase. Andésite noire, blanche. Roche éruptive essentiellement composée de cette pierre. ● andésite nom …   Encyclopédie Universelle

  • Andesite — ist der Name von: Andesite Creek, ein Fluss im US Bundesstaat Alaska Andesite (Kalifornien), eine Ortschaft im US Bundesstaat Kalifornien Andesite Lookout Tower, ein Aussichtsturm im US Bundesstaat Montana Andesite Peak, ein Berg im US… …   Deutsch Wikipedia

  • Andesīte — Andesīte, jüngere vulkanische Gesteine von porphyrartiger Struktur, bestehen aus einer in der Regel glasreichen Grundmasse und aus darin ausgeschiedenem Plagioklas (daneben zuweilen Sanidin), Hornblende und Augit, seltener Hypersthen und Glimmer …   Meyers Großes Konversations-Lexikon

  • Andesite — An des*ite, n. (Min.) An eruptive rock allied to trachyte, consisting essentially of a triclinic feldspar, with pyroxene, hornblende, or hypersthene. [1913 Webster] …   The Collaborative International Dictionary of English

  • andesite — [an′də zīt΄] n. [after ANDES (MOUNTAINS) + ITE1] a dark colored, fine grained, extrusive igneous rock consisting chiefly of plagioclase feldspars with some biotite, hornblende, or pyroxene …   English World dictionary

  • Andésite — Un échantillon d andésite (en noir) avec des cavités remplies de zéolite …   Wikipédia en Français

  • Andesite — For the extinct cephalopod genus, see Andesites. Andesite (pronEng|ˈændəsaɪt) is an igneous, volcanic rock, of intermediate composition, with aphanitic to porphyritic texture. The mineral assemblage is typically dominated by plagioclase plus… …   Wikipedia

  • andesite — andesitic /an deuh zit ik/, adj. /an deuh zuyt /, n. a dark colored volcanic rock composed essentially of plagioclase feldspar and one or more mafic minerals, as hornblende or biotite. [1840 50; named after ANDES; see ITE1] * * * Any member of a… …   Universalium

  • andesite — andezitas statusas T sritis chemija apibrėžtis Netolygiai grūdėtos struktūros, koryta efuzinė uoliena. atitikmenys: angl. andesite rus. андезит …   Chemijos terminų aiškinamasis žodynas

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