Thermochemical Sulfate Reduction: A Key Step in the Origin of Sediment-hosted Disseminated Gold Deposits.
Christopher H. Gammons, 1997. "Thermochemical Sulfate Reduction: A Key Step in the Origin of Sediment-hosted Disseminated Gold Deposits.", Carlin-Type Gold Deposits Field Conference, Peter Vikre, Tommy B. Thompson, Keith Bettles, Odin Christensen, Ron Parratt
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This paper will explore the significance of thermochemical sulfate reduction (TSR) to the origin of sediment-hosted disseminated gold (SHDG) deposits. TSR provides a means of generating abnormally high concentrations of H2S at moderate temperatures (e.g., 100 to 200°C). A high H2S content is a prerequisite for mobilizing gold and other metals associated with SHDG deposits (Ag, Hg, Sb, As), and is also necessary to form ore bodies with a high Au/Ag ratio. Field and sulfurisotopic evidence supporting the TSR hypothesis will be reviewed. The discussion will focus on SHDG deposits in the Carlin Trend and similar deposits in China, as well as the Hemlo gold deposit, Ontario, a possible Archean analog of this deposit type. If valid, the TSR hypothesis has significance to the minerals exploration industry as a means to discriminate between favorable vs. unfavorable source rocks.