The role of thermochemical sulfate reduction in the origin of Mississippi Valley‐type deposits. I. Experimental results

The kinetics of thermochemical sulfate reduction (TSR) were studied in experiments at 205–250°C, with determination of both sulfate and sulfide at intervals during the runs of up to 430 h. Analysis of the data indicates the reaction to have first‐order kinetics, and extrapolating these data, plus data from the literature, to 150°C gives a range of possible rate constants from 10⁰ to 10^?4 year^?1. Although the rate law has not been well established, a reasonable estimate allows calculation of the amount of sulfide ore formed as a function of flow conditions and time. It is here concluded that TSR could happen during the formation of Mississippi Valley‐type ore deposits, subject to several caveats.