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| Escoube, Raphaelle; Rouxel, Olivier; Edwards, Katrina; Glazer, Brian; Donard, Olivier F. X.. |
| Germanium (Ge) and Silicon (Si) exhibit similar geochemical behaviour in marine environments but are variably enriched in seafloor hydrothermal fluids relative to seawater. In this study, Ge isotope and Ge/Si ratio systematics were investigated in low temperature hydrothermal vents from Loihi Seamount (Pacific Ocean, 18°54’N, 155°15’W) and results were compared to high-temperature vents from the East Pacific Rise (EPR) at 9°50’N. Loihi offers the opportunity to understand contrasting Ge and Si behaviour in low temperature seafloor hydrothermal systems characterized by abundant Fe oxyhydroxide deposition at the seafloor. The results show that both Ge/Si and δ74/70Ge in hydrothermal fluids are fractionated relative to the basaltic host rocks. The enrichment... |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00273/38403/36728.pdf |
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| Rouxel, Olivier; Toner, Brandy; Germain, Yoan; Glazer, Brian. |
| Low-temperature hydrothermal vents, such as those encountered at Loihi Seamount, harbor abundant microbial communities and provide ideal systems to test hypotheses on biotic versus abiotic formation of hydrous ferric oxide (FeOx) deposits at the seafloor. Hydrothermal activity at Loihi Seamount produces abundant microbial mats associated with rust-colored FeOx deposits and variably encrusted with Mn-oxyhydroxides. Here, we applied Fe isotope systematics together with major and trace element geochemistry to study the formation mechanisms and preservation of such mineralized microbial mats. Iron isotope composition of warm (< 60 °C), Fe-rich and H2S-depleted hydrothermal fluids yielded δ56Fe values near +0.1 ‰, indistinguishable from basalt values.... |
| Tipo: Text |
Palavras-chave: Hydrothermal Systems; Seamounts; Iron Isotopes; Mineral deposits. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00405/51646/52195.pdf |
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