Sulfur contents at sulfide-liquid or anhydrite saturation in silicate melts; empirical equations and example applications

We present a new empirical equation for estimating sulfur content in silicate melts at anhydrite saturation based on available experimental results and an updated empirical equation for estimating sulfur content in silicate melts at sulfide-liquid saturation by adding relevant experimental data that were not previously used and excluding controversial experimental data. The fits of our empirical equations to the data used for calibration are within 10 percent error. Only total pressure, temperature, and silicate melt composition, parameters that are often known or can be reasonably assumed for natural magmatic systems, are required for utilization of the equations. The empirical equations are useful for petrologic modeling of natural magmatic systems, including magmatic hydrothermal ore deposits. Several example applications including the effect of decompression on sulfur content at sulfide-liquid saturation in komatiite and high Mg basaltic magmas and the ratio of silicate minerals to immiscible sulfide liquids during fractional crystallization of these magmas are provided.