Gold-rich volcanogenic massive sulphide deposits / Богатые золотом вулканогенные массивные сульфидные месторождения

Simplified definition A lens of iron-, copper-, zinc- and lead-sulphides, with significant amounts of silver and gold, formed on or below the sea floor by hot springs on and around submarine volcanoes. Scientific definition Gold-rich volcanogenic massive sulphide deposits (Au-VMS) are a sub-type of both volcanogenic massive sulphide (VMS) and lode gold deposits (Poulsen and Hannington, 1996; Hannington et al., 1999; Huston, 2000; Poulsen et al., 2000) (Fig.1). Like most VMS deposits, they consist of semi-massive to massive, concordant sulphide lenses underlain by discordant stockwork feeder zones. The main difference between Au-VMS and other VMS deposits is their gold concentration (in g/t Au), which exceeds the associated combined Cu, Pb, and Zn grades (in weight per cent). Gold is thus the main commodity. However, the polymetallic nature of this deposit sub-type makes it more resistant to fluctuating metal prices, resulting in a very attractive exploration target. Several gold-rich VMS deposits discussed by Hannington et al. (1999) and Huston (2000) are not included within this sub-type of gold deposits as their gold to base metal ratio is too low. <...>