Extreme S-34 depletions in ZnS at the Mike gold deposit, Carlin Trend, Nevada: Evidence for bacteriogenic supergene sphalerite

We identified submicrometer-sized framboidal sphalerite (ZnS) below the base of supergene oxidation in a Carlin-type gold deposit of Eocene age in Nevada, United States, where the framboidal sphalerite forms a blanket-like body containing >400,000 metric tons of zinc. Framboidal sphalerite <0.1 mum in diameter, formed in the early Miocene, ranges from <0.1 to 0.35 mol% FeS; the delta(34)S values range from -25% to w-70%, the lowest values measured in a marine or terrestrial environment. These S isotope data demonstrate the involvement of sulfate-reducing bacteria and provide the first documentation that sphalerite can form significant supergene sulfide-enrichment blankets.


Published in:
Geology, 31, 913-916
Year:
2003
Keywords:
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 Record created 2012-05-15, last modified 2018-03-17


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