Geochemistry of indium in magmatic-hydrothermal tin and sulfide deposits of the Herberton Mineral Field, Australia

Abstract The Herberton Mineral Field in Northeast Australia hosts world class magmatic-hydrothermal Sn–W polymetallic deposits that are enriched In. Baal Gammon and Isabel from the contains early tin, as cassiterite, overprinted by sulfide mineralization chalcopyrite, sphalerite, galena, pyrrhotite, stannite. We investigated distribution of In ores these two deposits, calculated temperature formation via sphalerite-stannite geothermometer, deduced physicochemical conditions favorable for enriching this mineralizing environment. deposit is dominated with contained average concentrations measured EPMA stannite 0.10, 0.68, 0.92 wt%, respectively. Chalcopyrite, sphalerite textures indicate incorporation occurred during exsolution an intermediate solid solution cubanite composition. associated galena only minor amounts chalcopyrite. concentration 0.11 wt%. stannite-sphalerite geothermometer indicates temperatures ~ 290 °C at deposit, 307 deposit. At temperatures, modeling suggests stable chlorine complexes occur acidic (pH < 3). These results when combined Eh–pH phase model assemblage further constrain redox mineralization.