Mineral chemistry of some mafic granulites from the Adirondack region

The mineral assemblages correspond with a reaction bundle containing an invariant point for granulite-facies metamorphism. Equilibrium is indicated by the observed correlation between amphibole and plagioclase compositions. The intercrystalline distribution of Mg and Fe (super 2+) depends on the intracrystalline occupancy of distorted cubic sites in which the Fe (super 2+) /Mg ratio is a positive function of the Ca content. Mineral and rock analyses for 11 mafic granulites are included.