Porphyry copper mineralization triggered by sulfate reduction and alkali metasomatism: Constraints from an experimental investigation

The potassium silicate (K-silicate) alteration zone is the main ore contributor in porphyry copper deposits worldwide. Knowledge of element behaviors and mineralization processes essential for an improved understanding mineralization, but they are still not well understood. In this study, we reacted synthetic Cl-rich fluids, containing K, Na, Cu, Mo, Zn, etc., with andesite a complex experimental system to simulate shallow process. We aimed bridge gap between simple studies natural systems evaluate contribution sulfate reduction formation its relationship early alkali metasomatism. results show that increasing temperature (from 300 500 °C) enhances K-silicate by promoting ion-exchange reactions, K-feldspar mainly formed transformation plagioclase via dissolution-reprecipitation processes. low-salinity vapor phase has stronger capacity than liquid at similar temperatures. addition, from °C favors further enhance metal sulfide precipitation. limited availability reduced sulfur fluid causes preferential precipitation Cu-(Mo) sulfides, while most Zn soluble fluid, Cu as sulfides much more efficient coexisting liquid. overlap triggered controlled several concomitant factors, e.g., relatively high (e.g., 400−500 °C), formation, decompression. Moreover, would promote changing compositions, removing K fluid.