Metamorphic Facies and Facies Series

Abstract

Goldschmidt’s (1911) study of the contact metamorphism of the Oslo area and Eskola’s (1914) study of the regional metamorphism of the Orijärvi region revealed that well-recrystallized metamorphic rocks approached chemical equilibrium at a stage of their history and that the mineral compositions they acquired then have usually been preserved over long subsequent periods of time. In a group of metamorphic rocks that have reached chemical equilibrium under the same definite P-T conditions, the mineral compositions of the rocks depend only on their bulk chemical compositions, regardless of their previous history. There exists a regular relationship between the mineral and chemical compositions of such metamorphic rocks. Eskola (1915) attempted to visualize the relationship by his ACF and A’KF diagrams.