Recalibration of the Equation for Calculating Water Content in Silicate Melt Equilibrated with Aqueous Fluid

Experience in using the previously obtained equation for predicting the limiting solubility of water in a silicate melt showed that for a number of experiments performed in the pressure range from 5 to 20 kbar, the calculated water contents are unrealistically high compared to the experimental values. The sample used in the previous work (containing the results of 412 experiments) was significantly supplemented with experiments from the MELT database. Based on the newly collected total sample consisting of 1241 experiments, the set of variables responsible for the effect of composition on water solubility was revised. The newly calibrated equation for calculating the limiting solubility of water allows an uncertainty of no more than ±0.01 mole fraction, or ±0.25 wt. % predict saturated water contents in silicate melts in the ranges: pressure from atmospheric to 20 kbar; temperatures from 825 to 1550 K, and the sample size used for optimization allows the equation to be used to calculate saturated water contents in a wide range of silicate melts, from komatiite basalts to rhyolites.