Calculated Phase Relations in High-Pressure Metapelites in the System NKFMASH Na2O---K2O---FeO---MgO---Al2O3---SiO2---H2O

Using an internally consistent thermodynamic dataset and updated models of activity---composition relation for solid solu-tions, petrogenetic grids in the system NKFMASH (Na2O---K2O---FeO---MgO---Al2O3---SiO2---H2O) and the subsystems NKMASH and NKFASH have been calculated with the soft-ware THERMOCALC 3.1 in the P---T range 5---36 kbar and 400---810C, involving garnet, chloritoid, biotite, carpholite, talc, chlorite, kyanite/sillimanite, staurolite, phengite, parago