Thermogenic Methane Production in Antarctic Subglacial Hydrocarbon Seeps

This dataset includes geochemical analyses of carbonate nodules collected at Elephant Moraine and the Pensacola Mountains, East Antarctica. Oxygen and uranium-series isotope analyses indicate that these carbonates precipitated from glacial meltwater during deglacial periods in the late Pleistocene. Carbonate δ13C values as low as -32.75 ‰ identify thermogenic methane as a primary carbon source, while clumped isotope measurements indicate formation temperatures of 12 - 20˚C, consistent with a geothermal origin. Lipid biomarker analyses further show that organic matter preserved in the nodules is highly thermally matured. These findings indicate that deep-sourced thermogenic methane migrated as hydrocarbon seeps to shallow pore spaces within basal sediments, demonstrating that geothermally active areas can be hotspots for methane accumulation below the Antarctic Ice Sheet. This material is based on services provided by the Polar Rock Repository with support from the National Science Foundation, under Cooperative Agreement OPP-2137467.