Eclogite ( /ˈɛklədʒaɪt/) is a metamorphic rock formed when mafic igneous rock is subjected to high pressure. ids. Green omphacite (+ late chlorite) + pink garnet + blue glaucophane + colorless phengite. Eclogite facies is determined by the temperatures and pressures required to metamorphose basaltic rocks to an eclogite assemblage. Study of eclogite rocks provides important information about what happens to ocean crust after it plunges into a subduction zone and thus provides insight into very deep mantle processes. Eclogite forms at pressures greater than those typical of the crust of the Earth. Eclogite is a metamorphic rock consisting of pyroxene omphacite and pyrope-rich garnet. This is high-pressure, medium- to high-temperature metamorphism. Importance of eclogite Photomicrograph of a thin section of eclogite from Turkey. C This article has been rated as C-Class on the project's quality scale. Some UHP rocks appear to record burial at depths greater than 120 km (75 mi) if diamond occurs in these rocks. Eclogite rheology is an important piece of information for understanding the subduction of continental crust to great depth and then return to the surface. Eclogite plays an important role in mantle convection and geodynamics in subduction zones. Eclogite-rich layers would be intermittent because of low melting points and the temperature-dependency of the relevant phase changes. Rocks are rated on the on the Moh's Hardness Scale which rates the rocks on the scale from 1 to 10. Hensen and R. Armstrong, This page was last edited on 10 August 2020, at 13:48. Eclogites record pressures over 1.2 GPa (170,000 psi) (45 km (28 mi) depth) at about 400 to 1,000 °C (752 to 1,832 °F) and usually over 600–650 °C (1,112–1,202 °F). Diamond and coesite occur as trace constituents in some eclogites and record particularly high pressures. 1. Harzburgitic diamonds typically have titaniferous pyrope, chromian spinel and chromian diopside inclusions, minerals which are not typically found in eclogites. Eclogite importance jamesbalmes208 is waiting for your help. What does eclogite mean? Xenoliths of eclogite occur in kimberlite pipes of Africa, Russia, Canada, and elsewhere. Posted on 24 October, 2012 by Metageologist. Eclogites containing lawsonite (a hydrous calcium-aluminium silicate) are rarely exposed at Earth's surface, although they are predicted from experiments and thermal models to form during normal subduction of oceanic crust at depths between about 45–300 km (28–186 mi). In some retrogressed eclogites and accompanying more silica-rich rocks, ultrahigh-pressure (UHP) metamorphism has been recognized only because of the preservation of coesite and/or diamond inclusions within trace minerals such as zircon and titanite. Eclogites are helpful in elucidating patterns and processes of plate tectonics because many represent oceanic crust that has been subducted to depths in excess of 35 km and then returned to the surface. Eclogite is a rare and important rock because it is formed only by conditions typically found in the mantle or the lowermost part of thickened crust.  The rarity of lawsonite eclogites therefore does not reflect unusual formation conditions but unusual exhumation processes. An unusually dense rock, eclogite can play an important role in driving convection within the solid Earth. A. Camacho, B.J. Eclogite is a rare and important rock because it is formed only by conditions typically found in the mantle or the lowermost part of thickened continental crust.. Eclogites are helpful in elucidating patterns and processes of plate tectonics because many represent oceanic crust that has been subducted to depths in excess of 35 km and then returned to the surface. ... eclogite residues is primarily ‘east-to-west’, and not ‘north-to-south’, as the amphibolite. Likewise, partial melting of eclogite has been modeled to produce tonalite-trondhjemite-granodiorite melts.  Transitional granulite-eclogite facies granitoid, felsic volcanics, mafic rocks and granulites occur in the Musgrave Block of the Petermann Orogeny, central Australia. Information and translations of eclogite in the most comprehensive dictionary definitions resource on the web. Eclogite is an important constituent of subduction slabs and plays a critical role in transporting surface materials (e.g., water) into the deep Earth. Removal of the dense lower continen tal crust is an important element of … "The importance of the Raudkleivane locality lies in the prograde metamorphism of eclogite within peridotite" In simpler words: in a 5000km2 large area, metamorphic eclogite can be found as pods in UHP gneiss formed as a part of the caledonian orogeny, in some places olivine bearing eclogite can be found in metamorphosed peridotite. Journal of Metamorphic Geology. Eclogite may completely retrogress to amphibolite or granulite during exhumation. Likewise, peridotite is a much more important source rock of common magmas. Be on the lookout for your Britannica newsletter to get trusted stories delivered right to your inbox. Eclogite is an unusually dense metamorphic rock, typically of basaltic composition, that represents a recorder and/or driving force for planetary-scale processes and evolution. Lawsonite eclogite is known from the U.S. (Franciscan Complex of California; xenoliths in Arizona); Guatemala (Motagua fault zone), Corsica, Australia, the Dominican Republic, Canada (British Columbia), and Turkey. H2O. Eclogite is part of WikiProject Geology, an attempt at creating a standardized, informative, comprehensive and easy-to-use geology resource. Ring in the new year with a Britannica Membership, This article was most recently revised and updated by, https://www.britannica.com/science/eclogite, University of California Santas Barbara - Earth Science - Eclogite Formation and the Rheology, Buoyancy, Seismicity, and H20 Content of Oceanic Crust. Eclogite is the highest pressure metamorphic facies and is usually the result of advancement from blueschist metamorphic conditions.