Carbon pool analysis of methane hydrate regions in the seafloor by accelerator mass spectrometry

Accelerator mass spectrometry for 14C was applied to the study of carbon pools associated with methane hydrate formations found in the seafloor at two continental margin sites. The Gulf of Mexico (GOM) site contains thermogenically produced methane that is ancient and thus free of 14C. The Cascadia Margin site contains biogenically produced methane, so may contain some 14C. This work reports on the 14C content of organic matter in the sediment at the GOM site, and of the methane in hydrates from both sites. In the GOM, the surface sediments contained ancient organic matter that was from 20% to 60% of the total organic carbon content. At both sites, the collected hydrates contained essentially no 14C