Encyclopedia of Astrobiology

Living Edition
| Editors: Muriel Gargaud, William M. Irvine, Ricardo Amils, Henderson James Cleaves, Daniele Pinti, José Cernicharo Quintanilla, Michel Viso

Greenschist Facies

Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-27833-4_675-3

Definition

Greenschist facies is one of the major subdivisions within the classification scheme of metamorphic rocks. Greenschist facies refers to low- to medium-grade metamorphic conditions corresponding to temperatures of about 300–500 °C and pressures of 3–20 kbar, corresponding to crustal depths of about 8–50 km. The name is derived from the green color of its characteristic minerals (chlorite) and the schistose fabric induced by recrystallization and deformation. Characteristic minerals are chlorite, actinolite, and albite ± epidote in metabasalt; chlorite, serpentine ± talc, tremolite, and brucite in meta-ultramafic rocks; and muscovite, garnet, and andalusite in metapelitic sediments. Greenschist facies prevails in the middle levels of oceanic crust and in the upper levels of orogenic belts. Many supracrustal rocks in Archean terranes are metamorphosed at greenschist facies, hence the name “greenstone belts.”

See Also

Keywords

Bioorganic Chemistry Classification Scheme Metamorphic Rock Orogenic Belt Green Color 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  1. 1.Maison des GéosciencesLGCA, Université J. FourierSt-Martin d’HèresFrance