Melting experiments on the forsterite–pyrope system at 8 and 13.5 GPa

The melting phase relations (melting curve of forsterite and binary eutectic composition) of the forsterite (Mg2SiO4)-pyrope (Mg3Al2Si3O12) system have been studied at 8 and 13.5 GPa. Forsterite is observed to melt incongruently into periclase + melt above about 8 GPa and the liquidus field of periclase gradually expands at higher pressures. The eutectic temperature is about 1850 degrees C at 8 GPa and about 2100 degrees C at 13.5 GPa, whereas the eutectic composition of the system is about 75 mol% forsterite at both pressures. (C) 1998 Elsevier Science B.V. All rights reserved.