amphibolite facies


amphibolite facies

One of the major divisions of the mineral facies classification of metamorphic rocks, encompassing rocks that formed under conditions of moderate to high temperatures (950°F, or 500°C, maximum) and pressures. Less-intense temperatures and pressures form rocks of the epidote-amphibolite facies, and more-intense temperatures and pressures form rocks of the granulite facies. Amphibole, diopside, epidote, plagioclase, certain types of garnet, and wollastonite are minerals typically found in amphibolite facies rocks. They are widely distributed in Precambrian gneisses and probably formed in the deeper parts of folded mountain belts.

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