Native S from seafloor hydrothermal sites: Messenger for magmatic degassing of metals into submarine hydrothermal systems

Abstract

Native S0 precipitates in form of little chimneys, submarine crater lakes, stains and crusts on sediments, and as crack and vesicle fillings in rocks at the seafloor hydrothermal sites. Unlike the biogenic native S0 precipitated in anoxic and euxinic seafloor environment, the seafloor hydrothermal native S0 is a result of either disproportionation of magmatic SO2 (δ34Ssample < δ34Sterrestrial mantle sulfide) or synproportionation of magmatic SO2 and H2S (δ34Ssample > δ34Sterrestrial mantle sulfide). Using it as a proxy for magmatic volatile flux we found out that it carried isotopic signal for magmatic degassing of Zn (δ66Znsample < δ66Znbulk silicate Earth). Thus, the seafloor hydrothermal native S0 provides new isotopic evidence for direct magmatic contribution of metals to seafloor hydrothermal systems and appears to be a messenger for magmatic volatile metal discharge in the ocean.