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Granite
GraniteGranite, which makes up 70–80% of Earth's crust , is an igneous rock formed of interlocking crystals of quartz , feldspar , mica, and other minerals in lesser quantities. Large masses of granite are a major ingredient of mountain ranges. Granite is a plutonic rock, meaning that it forms deep underground. Slow cooling gives atoms time to migrate to the surfaces of growing crystals, resulting in a coarse or mottled crystalline structure easily visible to the naked eye. Geologists have debated rival theories of granite's origin for over 150 years. The two theories most favored today are the magmatic theory and the hypermetamorphic theory. Supporters of the magmatic theory observe that granite is strongly associated with mountain ranges, which in turn tend to follow continental edges where one plate is being subducted (wedged under another). Tens of kilometers beneath the continental edge, the pressure and friction caused by subduction are sufficient to melt large amounts of rock. This melted rock or magma ascends toward the surface as large globules or plutons, each containing many cubic kilometers of magma. Apluton does not emerge suddenly onto the surface but remains trapped underground, where it cools slowly and may be repeatedly injected from beneath with pulses of fresh magma. To become surface rock, a solidified pluton must finally be uplifted to the surface and stripped bare by erosion . The ultrametamorphic theory, in contrast, argues that granite is not formed from raw magma but consists of sedimentary rock thoroughly melted and re-crystallized. Most geologists now argue that granites can be formed by magmatism, ultrametamorphosis, or a combination of both. Until recently, geologists thought that plutons of granitic magma would require millions of years to ascend to the surface. However, laboratory experiments with melted rock has shown that granitic magma is thin and runny enough (i.e., of low viscosity) to squirt rapidly upward to the surface through small cracks in the crust. Granite plutons may thus be created in 1,000–100,000 years, rather than in the millions of years previously thought. The precise origin and process of granite formation continues to be a subject of active research. See also Bowen's reaction series; Convergent plate boundary; Plate tectonics |
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"Granite." World of Earth Science. 2003. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. "Granite." World of Earth Science. 2003. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1G2-3437800262.html "Granite." World of Earth Science. 2003. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3437800262.html |
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granite
granite Granites are intrusive igneous rocks that contain large amounts of silica (SiO2). They contain minerals such as feldspar, which is white or pink, quartz, which is generally colourless, and either biotite, a flaky black mineral, amphibole, a black mineral, or both.
Granitic magma is thought to be generated in two ways: either by the melting of an existing rock or by the differentiation of a basaltic magma by fractional crystallization. In the process of fractional crystallization, denser magnesium-rich and silica-poor minerals crystallize and are separated from a melt, leaving it richer in silica. If a large volume of crystals is lost, the composition of the melt will be sufficiently modified to form a granite. Perhaps the most spectacular granite bodies are those of the cordilleras of North and South America: a series of batholiths extending from the Coast Range in Canada to Chile. Some of these plutons are of vast extent; the coastal batholith of Peru, for example, is more than 2400 km long and up to 65 km wide. Granites are not only strong and durable but also decorative; they are thus popular as facing stone for buildings, or as restaurant counters. They are particularly popular for the decoration of banks that wish to suggest financial durability. One of the most popular British granites for such purposes is the Shap granite, quarried on the Shap Fells in Cumbria, which is easily recognized by the large (2–3 cm) pink feldspar crystals in it. Judith M. Bunbury |
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PAUL HANCOCK and BRIAN J. SKINNER. "granite." The Oxford Companion to the Earth. 2000. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. PAUL HANCOCK and BRIAN J. SKINNER. "granite." The Oxford Companion to the Earth. 2000. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1O112-granite.html PAUL HANCOCK and BRIAN J. SKINNER. "granite." The Oxford Companion to the Earth. 2000. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O112-granite.html |
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granite
granite coarse-grained igneous rock of even texture and light color, composed chiefly of quartz and feldspars. It usually contains small quantities of mica or hornblende, and minor accessory minerals may be present. Depending on the feldspar present, granite may be pink, dark gray, or light gray. It is commonly believed to have solidified from molten rock (called magma) under pressure. However, some granites show no contacts with surrounding wall rock, but instead gradually grade into metamorphic rock. Others show relic features found in sediments. This evidence suggests that some granites are not igneous in origin, but metamorphic. Some granites are the oldest known rocks on earth; others were formed during younger geologic periods. Crystallized at depth, granite masses are exposed at the earth's surface by crustal movement or by the erosion of overlying rocks. Very coarse-grained granite, called pegmatite, may contain minerals and gemstones of economic value. Such pegmatites are found in the Black Hills of South Dakota. Granite has been used since ancient times as a building material. |
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"granite." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. "granite." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1E1-granite.html "granite." The Columbia Encyclopedia, 6th ed.. 2011. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1E1-granite.html |
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granite
granite. A general term for a class of very hard igneous rock consisting essentially of quartz, feldspar, and mica. Granite is one of the commonest of all rocks, found throughout the world, and it has many varieties, differing in texture and coarseness. It occurs in a wide range of colours—grey, green, rose, yellow—and the small scales of mica give it a lively sparkle. It takes a brilliant polish on a mirror-smooth surface and is extremely durable and resistant to weather, but it is one of the most difficult stones to carve. Consequently it has been used a good deal for building and paving but much less for sculpture—mainly for large outdoor works, most notably in ancient Egypt. Among modern sculptors, Masayuki Nagare has made memorable use of it.
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IAN CHILVERS. "granite." The Oxford Dictionary of Art. 2004. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. IAN CHILVERS. "granite." The Oxford Dictionary of Art. 2004. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1O2-granite.html IAN CHILVERS. "granite." The Oxford Dictionary of Art. 2004. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O2-granite.html |
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granite
granite A light-coloured, coarse-grained, igneous rock, consisting of essential quartz (at least 20%), alkali feldspar, mica (biotite and/or muscovite), with or more commonly without amphibole, and accessory apatite, magnetite, and sphene. Hypersolvus granites are characterized by one type of alkali feldspar, usually microperthite, whereas subsolvus granites are characterized by two types of alkali feldspar: microperthite and albite. Granite can be formed by partial melting of old continental crust, on a local scale by in situ replacement of continental crust (granitization), by fractional crystallization of basalt magma, or by a combination of these processes.
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AILSA ALLABY and MICHAEL ALLABY. "granite." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. AILSA ALLABY and MICHAEL ALLABY. "granite." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1O13-granite.html AILSA ALLABY and MICHAEL ALLABY. "granite." A Dictionary of Earth Sciences. 1999. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O13-granite.html |
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granite
gran·ite / ˈgranit/ • n. a very hard, granular, crystalline, igneous rock consisting mainly of quartz, mica, and feldspar and often used as a building stone. ∎ used in similes and metaphors to refer to something very hard and impenetrable: [as adj.] a man with granite determination. DERIVATIVES: gra·nit·ic / grəˈnitik/ adj. gran·it·oid / ˈgraniˌtoid/ adj. & n. ORIGIN: mid 17th cent.: from Italian granito, literally ‘grained,’ from grano ‘grain,’ from Latin granum. |
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"granite." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. "granite." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1O999-granite.html "granite." The Oxford Pocket Dictionary of Current English. 2009. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O999-granite.html |
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granite
granite. Coarse-grained hard igneous crystalline rock composed of feldspar, mica, and quartz, usually grey or dark red, and capable of taking a high polish. Used by the Ancient Egyptians (e.g. for obelisks), it was also employed by the Romans for, e.g. the shafts of columns. As industrialized methods of cutting stone developed in C19, the material was frequently used for ashlar work, and especially for funerary monuments in the new cemeteries.
Bibliography N. Davey (1961); |
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JAMES STEVENS CURL. "granite." A Dictionary of Architecture and Landscape Architecture. 2000. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. JAMES STEVENS CURL. "granite." A Dictionary of Architecture and Landscape Architecture. 2000. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1O1-granite.html JAMES STEVENS CURL. "granite." A Dictionary of Architecture and Landscape Architecture. 2000. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O1-granite.html |
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granite
granite Coarse-grained, light-grey, durable igneous rock, composed chiefly of feldspar and quartz, with some mica or hornblende. It is thought to have solidified from magma (molten rock). It is a valuable construction material.
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"granite." World Encyclopedia. 2005. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. "granite." World Encyclopedia. 2005. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1O142-granite.html "granite." World Encyclopedia. 2005. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O142-granite.html |
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granite
granite XVII. — It. granito lit. grained, granular, pp. formation on grano grain.
Hence granitic XVIII. |
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T. F. HOAD. "granite." The Concise Oxford Dictionary of English Etymology. 1996. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. T. F. HOAD. "granite." The Concise Oxford Dictionary of English Etymology. 1996. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1O27-granite.html T. F. HOAD. "granite." The Concise Oxford Dictionary of English Etymology. 1996. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O27-granite.html |
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granite
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ELIZABETH KNOWLES. "granite." The Oxford Dictionary of Phrase and Fable. 2006. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. ELIZABETH KNOWLES. "granite." The Oxford Dictionary of Phrase and Fable. 2006. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1O214-granite.html ELIZABETH KNOWLES. "granite." The Oxford Dictionary of Phrase and Fable. 2006. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O214-granite.html |
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granite
granite
•dammit, Hammett, Mamet
•emmet, semmit
•helmet, pelmet
•remit • limit • kismet • climate
•comet, grommet, vomit
•Goldschmidt
•plummet, summit
•Hindemith
•hermit, Kermit, permit
•gannet, granite, Janet, planet
•magnet • Hamnett • pomegranate
•Barnet, garnet
•Bennett, genet, jennet, rennet, senate, sennet, sennit, tenet
•innit, linnet, minute, sinnet
•cygnet, signet
•cabinet • definite • Plantagenet
•bonnet, sonnet
•cornet, hornet
•unit
•punnet, whodunnit (US whodunit)
•bayonet • dragonet • falconet
•baronet • coronet
•alternate, burnet
•sandpit • carpet • armpit • decrepit
•cesspit • bear pit • fleapit
•pipit, sippet, skippet, snippet, tippet, Tippett, whippet
•limpet • incipit • limepit
•moppet, poppet
•cockpit • cuckoo-spit • pulpit • puppet
•crumpet, strumpet, trumpet
•parapet • turnspit
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"granite." Oxford Dictionary of Rhymes. 2007. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. "granite." Oxford Dictionary of Rhymes. 2007. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1O233-granite.html "granite." Oxford Dictionary of Rhymes. 2007. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O233-granite.html |
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