Contribution of deep-sourced carbon from hydrocarbon seeps to sedimentary organic carbon: Evidence from radiocarbon and stable isotope geochemistry

Sulfate-driven anaerobic oxidation of methane (AOM) limits the release from marine sediments and promotes formation carbonates close to seafloor in seepage areas along continental margins. It has been established that hydrocarbon seeps are a source methane, dissolved inorganic carbon, organic carbon environments. However, questions remain about contribution deep-sourced sedimentary pool. In this study, we analyzed quantity, radiocarbon content (as percent modern pMC), stable isotopic compositions ?13C) matter enclosed within seep Gulf Mexico South China Sea assess if sediment may be used as proxy for intensity. The ?13C values (?13Corg) exhibited large range ?81.4‰ ?23.9‰. Radiocarbon contents carbonate-bound ranged 6% 28% pMC, suggesting is mixture particulate (?13C = ?22‰ VPDB 90% carbon) biomass resulting (assumed have 0% carbon). Assuming constant productivity photic zone, it proposed intensity duration most important factors controlling methane-derived column. This study reinforces potential using discern methane-rich environments ancient where authigenic carbonate not present constrain record AOM through Earth history.