The precious metal-rich, South Hercules mineralization, western Tasmania; a possible subsea-floor replacement volcanic-hosted massive sulfide deposit

South Hercules is a newly delineated, disseminated to semimassive base metal sulphide deposit with significant gold and silver grades. The deposit lies a kilometer along strike south from the Hercules mine, a 2.0Mt, polymetallic massive sulphide deposit in the Mount Read Volcanics belt, western Tasmania. The mineralization and alteration at the South Hercules deposit has been divided into two major facies: the mineralized sulphide facies and the carbonate facies. The form, texture, mineralogy, stable isotopes, and fluid inclusion data for the deposit suggest that it was formed largely by a subsea-floor replacement process from relatively low-temperature (150°-250°C), near-neutral fluids. The very low copper content and relatively high (Au+Ag)/Pb+Zn) ratio of the ores support a low-temperature environment in which gold was transported as the Au(HS)2- complex and Pb and Zn were transported as chloride complexes. -from Authors