greenschist

views updated

greenschist A low-grade, regional metamorphic rock, containing abundant chlorite with albite, epidote, and sericite, and possessing a distinct cleavage. Greenschists form by metamorphism of basic igneous rocks, the chlorite component being derived from the ferromagnesium minerals present in the original rock. Chlorite imparts a green colour to the cleaved rock, hence the name ‘greenschist’.

More From encyclopedia.com