Rare earth elements of seep carbonates: Indication for redox variations and microbiological processes at modern seep sites |
| |
| Institution: | 1. MARUM — Center for Marine and Environmental Sciences and Department of Geosciences, University of Bremen, 28334 Bremen, Germany;2. IFREMER, Unité de Recherche Géosciences Marines, 29280 Plouzané, France;3. Institute of Geology, University of Hamburg, 20146 Hamburg, Germany;4. State Key Laboratory for Mineral Deposits Research, Department of Earth Sciences, Nanjing University, Nanjing 210093, China;5. Department of Geodynamics and Sedimentology, Center for Earth Sciences, University of Vienna, 1090 Vienna, Austria;1. Institute of Earth Sciences, St. Petersburg State University, University Emb. 7/9, 199034 St. Petersburg, Russia;2. Institute of Geography, Russian Academy of Sciences, Staromonetniy lane, 29, 119017 Moscow, Russia;3. Geological Institute of RAS, Pyzhevski Lane 7, 119017 Moscow, Russia;4. University of Texas, Jackson School of Geosciences, 2305 Speedway Stop C1160, Austin, TX 78712-1692, United States of America;5. Faculty of Biology, St. Petersburg State University, University Emb. 7/9, 199034 St. Petersburg, Russia;6. Zavaritsky Institute of Geology and Geochemistry, Ural Branch of Russian Academy of Science, 620016 Ekaterinburg, 15 Academika Vonsovskogo str., Russia;7. Kola Science Center of the Russian Academy of Sciences, 184209, Murmansk district, Apatity, Fersmana Str, 14, Russia |
| |
| Abstract: | At marine seeps, methane is microbially oxidized resulting in the precipitation of carbonates close to the seafloor. Methane oxidation leads to sulfate depletion in sediment pore water, which induces a change in redox conditions. Rare earth element (REE) patterns of authigenic carbonate phases collected from modern seeps of the Gulf of Mexico, the Black Sea, and the Congo Fan were analyzed. Different carbonate minerals including aragonite and calcite with different crystal habits have been selected for analysis. Total REE content (ΣREE) of seep carbonates varies widely, from 0.1 ppm to 42.5 ppm, but a common trend is that the ΣREE in microcrystalline phases is higher than that of the associated later phases including micospar, sparite and blocky cement, suggesting that ΣREE may be a function of diagenesis. The shale-normalized REE patterns of the seep carbonates often show different Ce anomalies even in samples from a specific site, suggesting that the formation conditions of seep carbonates are variable and complex. Overall, our results show that apart from anoxic, oxic conditions are at least temporarily common in seep environments. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
