How carbonate dissolution facilitates sediment-hosted Zn-Pb mineralization

Abstract Most of the world's Zn and Pb is extracted from sediment-hosted Zn-Pb deposits. The deposits hosted in carbonate rocks are hypothesized to form by mixing acidic metal-bearing brines with reduced sulfur-bearing fluids while dissolving sedimentary carbonate. To test role this process, we conducted hydrothermal experiments simulating ore formation reacting ± Ba–bearing H2S SO42– produced native sulfur, without minerals (calcite or dolomite crystals), at 200 °C water-saturated pressure. Sphalerite, galena, barite (or anhydrite) crystals formed only when was present experiment, accompanied dissolution. textures sphalerite clusters similar those observed ancient modern Thermodynamic modeling 150 250 demonstrates that metal-rich causes most solution precipitate as dissolution occurs buffer pH, consistent experimental observations. need for a pH increases increasing temperature, different buffers may play deposit types. We propose carbonate-buffered fluid critical process forming post-sedimentary Ba rocks.