greenschist


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greenschist

[′grēn‚shist]
(petrology)
A schistose metamorphic rock with abundant chlorite, epidote, or actinolite present, giving it a green color.
References in periodicals archive ?
This is based on the following evidences: Field relations between the different lithotypes of metabasites reflect the occurrence of a prograde metamorphism, which is manifested by an increase of metamorphism from the greenschist facies (chlorite and actinolite schists with or without garnet, and metabasalts) to the amphibolite facies (amphibolites with or without garnet).
The northwestern and youngest Geotectonic Province of Santa Marta (GPSM) comprises an inner sub-belt of Cretaceous imbricated metamorphic rocks (greenschists and amphibolites) and an outer sub-belt of Mesozoic amphibolites, greenschists and phyllites separated by the lower to middle Cenozoic Santa Marta Batholith (Doolan, 1970; MacDonald, et al., 1971).
The bedrock is of Cambro-Silurian origin (amphibolite, greenschist, and calcareous phyllite) and the Quaternary deposits consist of peat, till, glacifluvial, and loessic accumulations.
Lithologies metamorphosed to the greenschist facies have a contact at mile marker 16.5 along US Highway #64 in the Ocoee Gorge.
Whereas [D.sub.1] and [D.sub.2] developed under amphibolite and greenschist facies metamorphic conditions, [D.sub.3] represents an event leading to the development of kink bands, localized shear zones, and slickensides along the thrust sheet of the Qatruyeh area [47].
Host structures are mainly shear zones and brittle faults developed within the metabasalt unit of the Marraba Volcanics which has been metamorphosed to greenschist and amphibolite.
The Kagi Metamorphics are composed of leucocratic felsic chlorite-muscovite -quartz-feldspar schist (low grade greenschist facies), some garnet-mica schist and minor metabasite (Department of Mineral Resources, unpublished).
floridana haematoreia: range 671-975 m; Table 1) in the Greenschist and Amphibolite Metamorphic Facies Zones of the Blue Ridge Belt (North Carolina Geologic Survey, 1985).
The complex zonation of amphiboles suggest that the Sona amphibolites had undergone an counterclockwise regional metamorphism progressive from the greenschist facies to the hornblende plagioclase amphibolite facies at low to medium pressure and temperature (350 to 650[degrees]c).
Schist: composed of biotite and quartz, and chlorite and quartz (greenschist); schistocity is well defined, and sometimes folding is seen.
The hydrothermal alteration of the samples varies from literally fresh rocks to true greenschist facies rocks.

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