Experimental constraints of metamorphic pressure and temperature, and phase relations of a phlogopite-bearing orthopyroxene granulite from Howard Hills, Napier Complex, East Antarctica
Journal of Mineralogical and Petrological Sciences
High pressure and high temperature experiments were carried out at 9 13 kbar and 950 1200°C using a piston cylinder apparatus, simulating the equilibrium conditions of a phlogopite bearing orthopyroxene granulite from the Howard Hills, Napier Complex, East Antarctica. This granulite consists of orthopyroxene, sapphirine, spinel, alkali feldspar and F rich phlogopite with minor amounts of plagioclase, rutile and quartz, and is garnet free. The experiments clarified the equilibrium phase
... rium phase relations of the phlogopite bearing orthopyroxene granulite under ultrahigh temperature metamorphism conditions. The following mineral assemblages were obtained with decreasing rutile. Liquid was found in run products at 9 kbar and temperatures of ≥1100°C, and at pressures of 11 13 kbar and 1150°C. At higher pressure, garnet coexists with orthopyroxene, alkali feldspar, plagioclase, phlogopite, sapphirine, rutile and spinel. These experimental results constrain the P T conditions of garnet free, phlogopite bearing orthopyroxene granulite from the Howard Hills.