Definitions

from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun A gray, fine-grained volcanic rock consisting chiefly of plagioclase feldspar and one or more mafic minerals.

from The Century Dictionary.

  • noun A volcanic rock of wide-spread occurrence, especially in the Cordilleran region of North America.

from the GNU version of the Collaborative International Dictionary of English.

  • noun (Min.) An eruptive rock allied to trachyte, consisting essentially of a triclinic feldspar, with pyroxene, hornblende, or hypersthene.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun geology A class of fine-grained intermediate igneous rock, of volcanic origin, containing mostly plagioclase feldspar.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • noun a dark grey volcanic rock

Etymologies

from The American Heritage® Dictionary of the English Language, 4th Edition

[After the Andes.]

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Examples

  • A third type of magma, called andesite, named after the Andes Mountains where it is often found, is composed of a mixture of both felsic and mafic magma.

    PhysOrg.com - latest science and technology news stories 2010

  • (FeCO3), used as a pigment, and also found in the Kirtland shale; and various metamorphic and igneous rocks (such as andesite, schist, gabbro, slate, and olivine), which could have been picked up in the river

    Tseh So, a Small House Ruin, Chaco Canyon, New Mexico : 1937

  • The Miocene volcanic rocks are mostly andesite, basalt, and pyroclastic rocks.

    Santa Monica Mountains (Bailey) 2009

  • St. Lucia, and Martinique are predominantly composed of acid andesite and dacitic rocks.

    Grenada 2009

  • The western Cascades are older and more eroded than the lava plateau and prominent snow-covered cones of the high Cascades (Ecoregions 4c and 4d); they are composed of dark basalt in contrast to the gray andesite of the high Cascades.

    Ecoregions of Oregon (EPA) 2009

  • Miocene basalt, andesite, pyroclastic, and marine sedimentary rocks predominate in this subsection.

    Northern Channel Islands (Bailey) 2009

  • Floral mapping of the nominated area recognizes 5 broad communities including the dolomite grasslands, andesite mountain bushveld, witwatersrand mountain bushveld, VD granite grassland and the riverine bushland.

    Vredefort Dome, South Africa 2009

  • The Volcanic Mid-Elevation Forests ecoregion occurs at elevations of about 7500 to 10,000 feet and is composed of igneous rocks of andesite and basalt.

    Ecoregions of New Mexico (EPA) 2009

  • Basalt magma typically generates very little ash compared to other types (andesite, dacite, and rhyolite).

    volcanic ash hazards and ways to minimize them 2009

  • Typically occurring in Virginia are basalt and metabasalt of the Catoctin Formation, granite and granodiorite of the Virginia Blue Ridge Complex, and andesite, tuft, and greenstone of the Swift Run Formation.

    Ecoregions of Delaware, Maryland, Pennsylvania, Virginia, and West Virginia (EPA) 2008

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