eclogite

/ek"leuh juyt'/, n.
a rock consisting of a granular aggregate of green pyroxene and red garnet, often containing kyanite, silvery mica, quartz, and pyrite.
[1815-25; < Gk eklog(é) selection (see ECLOGUE) + -ITE1]

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Any member of metamorphic rocks whose original composition is similar to that of basalt.

Eclogites consist primarily of green pyroxene (omphacite) and red garnet (pyrope), with small amounts of various other minerals such as kyanite and rutile. These minerals in the eclogite are the result of reactions in originally igneous minerals having been subjected to extremely high pressures and moderate to relatively high temperatures.

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rock
      any member of a small group of igneous and metamorphic rocks whose composition is similar to that of basalt. Eclogites consist primarily of green pyroxene (omphacite) and red garnet (pyrope), with small amounts of various other stable minerals—e.g., rutile. They are formed when volcanic or metamorphic rocks rich in such mafic minerals are subjected to extremely high pressures and moderate to relatively high temperatures. Laboratory experiments have revealed that eclogites will crystallize from basaltic magma under very high pressure conditions common to the deeper portions of the Earth's upper mantle, the mantle constituting the layer that lies between the crust and core and that comprises about two-thirds of the planet's bulk. These conditions are found in subduction zones where the ocean floor is forced beneath a continental margin—such as in the Cascadia subduction zone off the coast of western North America and the Sunda Trench subduction zone off the western coast of Sumatra, Indon. Many investigators believe that eclogite is representative of numerous parts of the upper mantle. In the crust, eclogites generally occur as xenoliths (i.e., foreign inclusions) in igneous rocks and as isolated blocks measuring as much as 100 m (328 feet) across in metamorphic rocks. Interestingly, eclogites somewhat resemble chondritic meteorites in composition (see chondrite).

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Universalium. 2010.

Look at other dictionaries:

  • Eclogite — (pronEng|ˈɛklədʒaɪt) is a coarse grained mafic (basaltic in composition) metamorphic rock. Eclogite is of special interest for at least two reasons. First, it forms at pressures greater than those typical of the crust of the Earth. Second, being… …   Wikipedia

  • Éclogite — de Norvège Une éclogite (du grec eklogê, choix) est une roche métamorphique qui s est formée dans le faciès éclogitique, c est à dire ayant subi les conditions de pression et température de ce champ. Historiquement, Eskola a défini les faciès… …   Wikipédia en Français

  • Eclogite — Éclogite Éclogite de Norvège Une éclogite (du grec eklogê, choix) est une roche métamorphique qui s est formée dans le faciès éclogitique, c est à dire ayant subi les conditions de pression et température de ce champ. Historiquement, Eskola a… …   Wikipédia en Français

  • Eclogite — Ec lo*gite, n. [See {Ecloque}.] (Min.) A rock consisting of granular red garnet, light green smaragdite, and common hornblende; so called in reference to its beauty. [1913 Webster] …   The Collaborative International Dictionary of English

  • éclogite — ● éclogite nom féminin (grec eklogê, choix) Roche métamorphique très dense, constituée essentiellement de pyroxène sodique et de grenat, formée à très haute pression dans un vaste domaine de températures …   Encyclopédie Universelle

  • eclogite — ˈekləˌjīt noun ( s) Etymology: French éclogite, from Greek eklogē selection + French ite : a metamorphic rock consisting of soda rich pyroxene and magnesia rich garnet as essential minerals …   Useful english dictionary

  • eclogite — noun a coarse grained metamorphic rock, a mixture of pyroxene, quartz and feldspar with inclusions of red garnet …   Wiktionary

  • eclogite — [ ɛklɒdʒʌɪt] noun Geology a metamorphic rock containing granular minerals, typically garnet and pyroxene. Origin C19: from Fr., from Gk eklogē selection + ite1 …   English new terms dictionary

  • eclogite — ec·lo·gite …   English syllables

  • eclogite — /ˈɛklədʒaɪt/ (say ekluhjuyt) noun a rock consisting of granular aggregate of green pyroxene and red garnet, often also containing kyanite, silvery mica, quartz, and pyrite. {Greek eklogē selection + ite1} …   Australian English dictionary

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