The solubility of corundum in H 2O at high pressure and temperature and its implications for Al mobility in the deep crust and upper mantle

Abstract

The solubility of corundum in H 2O was measured at 700–1100 °C and 0.5–2.0 GPa using a piston–cylinder apparatus and weight-loss methods. At 700 °C, 0.5 GPa, Al concentration is 0.41 ± 0.15 millimolal (1 σ analytical error). Corundum solubility increases strongly with pressure ( P) and temperature ( T), reaching 2.57 ± 0.15 millimolal at 700 °C, 2.0 GPa, and 27.3 ± 1.5 millimolal at 1100 °C, 2.0 GPa. The results were fitted with the equation log m Al = 1.131 + 3827 / T − (2.277 − 7336 / T)log ρ H 2O , where m Al is molality of Al, ρ H 2O is the density of H 2O in g/cm 3, and T is in Kelvin. The data indicate that Al can have significant solubility in H 2O during metamorphic and metasomatic processes in the deep crustal and upper mantle.