Class of high-grade medium to coarse grained metamorphic rocks
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A sample of granulite-facies metamorphic rock of felsic composition, with garnet porphyroblasts
Granulites are a class of high-grade metamorphic rocks of the granulite facies that have experienced high-temperature and moderate-pressure metamorphism. They are medium to coarse–grained and mainly composed of feldspars sometimes associated with quartz and anhydrous ferromagnesian minerals, with granoblastic texture and gneissose to massive structure.[1] They are of particular interest to geologists because many granulites represent samples of the deep continental crust. Some granulites experienced decompression from deep in the Earth to shallower crustal levels at high temperature; others cooled while remaining at depth in the Earth.
The minerals present in a granulite will vary depending on the parent rock of the granulite and the temperature and pressure conditions experienced during metamorphism. A common type of granulite found in high-grade metamorphic rocks of the continents contains pyroxene, plagioclase feldspar and accessory garnet, oxides and possibly amphiboles. Both clinopyroxene and orthopyroxene may be present, and in fact, the coexistence of clino- and orthopyroxene in a metabasite (metamorphed basalt) defines the granulite facies.
A granulite may be visually quite distinct with abundant small pink or red pyralspite garnets in a 'granular' holocrystalline matrix. Concentrations of garnets, micas, or amphiboles may form along a linear pattern resembling gneiss or migmatite banding.
Eclogite
Blueschist
Greenschist
Prehnite- Pumpellyite
Zeolite
Granulite
Amphibolite
Hornfels
Sanidinite
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Diagram showing metamorphic facies in pressure-temperature space. The domain of the graph corresponds to circumstances within the Earth's crust and upper mantle.
^D.R. Bowes (1989), The Encyclopedia of Igneous and Metamorphic Petrology; Van Nostrand Reinhold ISBN 0-442-20623-2
Granulites are a class of high-grade metamorphic rocks of the granulite facies that have experienced high-temperature and moderate-pressure metamorphism...
Survey strongly discourages the use of granulite as a classification for rock metamorphosed to the granulite facies. Instead, such rock will often be...
the resulting fractionated granulite rises steeply in the crust, water exits from its supercriticality phase, the granulite starts to crystallize, becomes...
The Lapland Granulite Belt is an elongate and arcuate zone of granulite rock in the Cap of the North spanning areas within Norway, Finland and Murmansk...
as granulites in the lower continental crust at high thermal gradients. This leads to significant extraction of hydrous felsic melts from granulite-facies...
calcite + diopside ± forsterite (higher pressure and temperature) The granulite facies is the highest grade of metamorphism at medium pressure. The depth...
tectonic province, a Neoproterozoic mobile belt known as the Southern Granulite Terrane (SGT) or Pandyan Mobile Belt. This geologic province represents...
tectonic activity until 1.05 Ga. It was at this point that the Central Granulite Terrane was exhumed and minor magmatism occurred. The reason for change...
areas of regional metamorphism that reaches the middle amphibolite to granulite metamorphic facies. In other words, the rock was metamorphosed at a temperature...
quartz-feldspar rock formed at high temperature and pressure, commonly found in granulite facies’ metamorphic regions, sensu stricto as an endmember of the charnockite...
have been faulted southward over continental crust composed of Archean granulites of the Indian Plate during the Cenozoic collision of India with Asia....
high temperature but variable pressure. Example rocks include gneiss and granulite. It occurs with andalusite, kyanite, potassium feldspar, almandine, cordierite...
Geological Survey strongly discourages use of granulite as a classification for rock metamorphosed to the granulite facies. Instead, such rock will often be...
the Central Region was the 2.5 Ga granulite facies Badcallian event. The Northern Region lacks evidence of granulite facies and in the Southern Region...
formed of a great variety of metamorphic and igneous rocks, including granulite and granite. Oceanic crust is composed primarily of basalt and gabbro...
formed under high pressure Gneiss – Common high-grade metamorphic rock Granulite – Class of high-grade medium to coarse grained metamorphic rocks Greenschist –...
aluminous mineral assemblages from the prehnite-pumpellyite facies to the granulite facies, as well as the blueschist facies and eclogite facies at higher...
550 million years ago, an event known as the Woodroffe Thrust lifted granulite facies rocks northward over low-grade metamorphic rocks. The eventual...
water. In dry rocks, however, additional heat (and burial) may result in granulite facies conditions. Uralite is a particular hydrothermally altered pyroxenite;...
facies, EA = Epidote-Amphibolite facies, AM = Amphibolite facies, GRA = Granulite facies, UHT = Ultra-High Temperature facies, HAE = Hornfels-Albite-Epidote...
lies on Precambrian strata, some of it dating back 2 billion years. The granulite facies rocks of the Highland Series (gneisses, sillimanite-graphite gneisses...
carbonation reactions occur in ultramafic rocks at lower greenschist through to granulite facies metamorphism when the rock in question is subjected to metamorphism...
California Coast Ranges. Transitional granulite-eclogite facies granitoid, felsic volcanics, mafic rocks and granulites occur in the Musgrave Block of the...
creation of Pangaea and Rodinia. Secular trends such as carbonatites, granulites, eclogites, and greenstone belt deformation events are all possible indicators...
plutonic belts surrounded by the vast gneissic terrain. The southern granulite - gneiss terrain of Tamil Nadu - Kerala. The Eastern Ghat Mobile Belt...
Calvin F. (May 2004). "Precise Time and Conditions of Peak Taconian Granulite Facies Metamorphism in the Southern Appalachian Orogen, U.S.A., with Implications...
occurs in relatively high-temperature metamorphic rocks such as mafic granulite and metamorphosed iron formations. It commonly occurs in association with...
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