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Sphalerite oxidation in seawater with covellite: Implications for seafloor massive sulfide deposits and mine waste

November 25, 2020

Metal sulfide minerals exist in several marine environments and are in thermodynamic disequilibrium with oxygenated seawater from the time of their formation. Oxidation is both ubiquitous and heterogeneous, as observational and experimental evidence demonstrates that sulfide minerals may oxidize completely on decadal timescales (hydrothermal plumes) or incompletely in billions of years (mineral deposits); however, the processes, rates, and interactions among minerals as oxidative dissolution occurs are not well understood. Added impetus to understanding these processes exists due to the potential for mining of seafloor massive sulfide deposits and potential environmental impacts of that activity. Here, we present a laboratory-based experimental study on the galvanic oxidation of sphalerite and synthesized zinc sulfide and coupled to covellite. We find that, in contrast to single-mineral reactions, coupled mineral reactions are at least 2 orders of magnitude more rapid, light independent, and have a lower apparent activation energy for oxidation. These results begin to provide insight into observed differences between laboratory and environmentally observed oxidation rates and are a step in the direction of more accurately predicting environmental rates as well as any changes to those rates from anthropogenic disturbances.

Citation Information

Publication Year 2020
Title Sphalerite oxidation in seawater with covellite: Implications for seafloor massive sulfide deposits and mine waste
DOI 10.1021/acsearthspacechem.0c00177
Authors Amy Gartman, Samantha P. Whisman, James R. Hein
Publication Type Article
Publication Subtype Journal Article
Series Title ACS Earth and Space Chemistry
Index ID 70216785
Record Source USGS Publications Warehouse
USGS Organization Pacific Coastal and Marine Science Center