TY - SER ID - feng2013reeo T1 - Rare earth elements of modern seeps from the Gulf of Mexico, the Black Sea, and the Congo Fan AU - Feng, Dong AU - Lin, Zhijia AU - Bian, Y AU - Chen, Duofu AU - Peckmann, Jörn AU - Bohrmann, Gerhard AU - Roberts, Harry H PY - 2013 T2 - Supplement to: Feng, D et al. (2013): Rare earth elements of seep carbonates: Indication for redox variations and microbiological processes at modern seep sites. Journal of Asian Earth Sciences, 65, 27-33, https://doi.org/10.1016/j.jseaes.2012.09.002 PB - PANGAEA DO - 10.1594/PANGAEA.834248 UR - https://doi.org/10.1594/PANGAEA.834248 N2 - 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 (SumREE) of seep carbonates varies widely, from 0.1 ppm to 42.5 ppm, but a common trend is that the SumREE in microcrystalline phases is higher than that of the associated later phases including micospar, sparite and blocky cement, suggesting that SumREE 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. ER -