Journal article

Amphibolites with staurolite and other aluminous minerals: calculated mineral equilibria in NCFMASH

J Arnold, R Powell, M Sandiford

JOURNAL OF METAMORPHIC GEOLOGY | BLACKWELL SCIENCE INC | Published : 2000

Abstract

Amphibolite facies mafic rocks that consist mainly of hornblende, plagioclase and quartz may also contain combinations of chlorite, garnet, epidote, and, more unusually, staurolite, kyanite, sillimanite, cordierite and orthoamphiboles. Such assemblages can provide tighter constraints on the pressure and temperature evolution of metamorphic terranes than is usually possible from metabasites. Because of the high variance of most of the assemblages, the phase relationships in amphibolites depend on rock composition, in addition to pressure, temperature and fluid composition. The mineral equilibria in the Na2O-CaO-FeO-MgO-Al2O3-SiO2-H2O (NCFMASH) model system demonstrate that aluminium content i..

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