|Giora Proskurowski, M D Lilley, J S Seewald, G L Fruh-Green, E Olson, J E Lupton, S P Sylva, D S Kelley, Abiogenic Hydrocarbon Production at Lost City Hydrothermal Field, Science, 01 Feb 08|
Low molecular weight hydrocarbons in natural hydrothermal fluids have been attributed to abiogenic production by Fischer-Tropsch type (FTT) reactions, although clear evidence for such a process has been elusive. Here we present concentration, and stable and radiocarbon isotope data from hydrocarbons dissolved in hydrogen-rich fluids venting at the ultramafic-hosted Lost City Hydrothermal Field. A distinct ?inverse? trend in the stable carbon and hydrogen isotopic composition of C1-C4 hydrocarbons is compatible with FTT genesis. Radiocarbon evidence rules out seawater bicarbonate as the carbon source for FTT reactions, suggesting a mantle-derived inorganic carbon source leached from the host rocks. Our findings illustrate that the abiotic synthesis of hydrocarbons in nature may occur in the presence of ultramafic rocks, water, and moderate amounts of heat.
Free access to full text on-line
FILE » Lost City Mosaic
Mosaic of a 30m carbonate tower at Lost City