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metasomatism
metasomatism Metasomatism is a type of metamorphism caused by reaction between the minerals in the original rock and hot fluids that have passed through it. These fluids flush specific elements in or out of the rock, thereby changing its overall chemical composition, which thus distinguishes the process from other kinds of metamorphism.
The usual situation in which metasomatism occurs is when igneous rock, especially a large body such as a granite pluton, is intruded into water-bearing sediments. The heat of the igneous body initiates convection of the water, which is heated as it is drawn into the body and carries heat away after it becomes warm and buoyant, only to be replaced by cooler water drawn in from the sides. Such a hydrothermal circulation system can survive for hundreds of thousands of years. The consequent dissolution and precipitation of chemical elements by the hydrothermal fluids can be responsible for major redistribution of elements, and in some cases their concentration into economic ore deposits. For example, hydrothermal circulation and metasomatic redistribution of elements around igneous intrusions in the Andes is responsible for the world's largest copper deposits, and the ‘china clay’ of Cornwall is the metasomatized remains of granite that has been thoroughly rotted to leave a residue of the clay mineral kaolinite. David A. Rothery |
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Cite this article
PAUL HANCOCK and BRIAN J. SKINNER. "metasomatism." The Oxford Companion to the Earth. 2000. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>. PAUL HANCOCK and BRIAN J. SKINNER. "metasomatism." The Oxford Companion to the Earth. 2000. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1O112-metasomatism.html PAUL HANCOCK and BRIAN J. SKINNER. "metasomatism." The Oxford Companion to the Earth. 2000. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O112-metasomatism.html |
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skarn
skarn A contact metamorphic rock (see CONTACT METAMORPHISM) composed of calcium, magnesium, and iron silicates (with or without iron, copper, and manganese sulphides and oxides) which has been derived from limestone or dolomite by the metasomatic (see METASOMATISM) introduction of large amounts of silicon, aluminium, iron, and magnesium from a nearby igneous intrusion, usually a granite. Many skarns serve as host rocks for economic deposits of magnetite and copper sulphides.
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Cite this article
AILSA ALLABY and MICHAEL ALLABY. "skarn." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>. AILSA ALLABY and MICHAEL ALLABY. "skarn." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1O13-skarn.html AILSA ALLABY and MICHAEL ALLABY. "skarn." A Dictionary of Earth Sciences. 1999. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O13-skarn.html |
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metasomatism
metasomatism Kind of metamorphism that involves the introduction of chemical constituents into a rock, or their removal from it (or both), via a volatile phase. Complete mineral transformations may occur, but the original rock texture may remain (resulting in a pseudomorph).
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Cite this article
AILSA ALLABY and MICHAEL ALLABY. "metasomatism." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>. AILSA ALLABY and MICHAEL ALLABY. "metasomatism." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1O13-metasomatism.html AILSA ALLABY and MICHAEL ALLABY. "metasomatism." A Dictionary of Earth Sciences. 1999. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O13-metasomatism.html |
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skarn
skarn
•Abadan, Abidjan, Amman, Antoine, Arne, Aswan, Avon, Azerbaijan, Baltistan, Baluchistan, Bantustan, barn, Bhutan, Dagestan, darn, dewan, Farne, guan, Hahn, Hanuman, Hindustan, Huascarán, Iban, Iran, Isfahan, Juan, Kazakhstan, khan, Koran, Kurdistan, Kurgan, Kyrgyzstan, macédoine, Mahon, maidan, Marne, Michoacán, Oman, Pakistan, pan, Pathan, Qumran, Rajasthan, Shan, Siân, Sichuan, skarn, soutane, Sudan, Tai'an, t'ai chi ch'uan, Taiwan, Tajikistan, Taklimakan, tarn, Tatarstan, Tehran, Tenochtitlán, Turkestan, Turkmenistan, tzigane, Uzbekistan, Vientiane, yarn, Yinchuan, yuan, Yucatán
•Autobahn • Lindisfarne
•Bildungsroman • Nisan • Khoisan
•Afghanistan • bhagwan • Karajan
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Cite this article
"skarn." Oxford Dictionary of Rhymes. 2007. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>. "skarn." Oxford Dictionary of Rhymes. 2007. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1O233-skarn.html "skarn." Oxford Dictionary of Rhymes. 2007. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O233-skarn.html |
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