Research scientist Qi Fu of the University of Minnesota will be leading a seminar on Abiotic Hydrocarbons this Friday: LPI Seminar Series: Experimental investigations on abiotic formation of hydrocarbons under hydrothermal conditions.
Qi Fu, Univ. of MinnesotaAlso see here.
Experimental investigations on abiotic formation of hydrocarbons under hydrothermal conditions
A series of experiments were conducted to study mineral catalyzed carbon reduction processes in subseafloor hydrothermal systems. In experiments involving magnetite and CO2 and H2-bearing aqueous fluids at 400oC and 500 bars, time-series fluid samples indicated significant concentrations of dissolved CO and C1-C3 hydrocarbons and relatively large changes in dissolved CO2 and H2 concentrations, consistent with formation of additional hydrocarbons beyond C3. The isotope results showed a pattern of C and H isotope enrichment between C1 and higher hydrocarbons. The "isotopic reversal" trend was not observed for 13C values of dissolved alkanes with increasing carbon number. This may relate to the specific mechanism of carbon reduction under hydrothermal conditions at elevated temperatures and pressures. In another experiment, the catalytic role of iron-nickel sulfide (Pentlandite) was evaluated using a 13C-labeled carbon source at conditions (T, P, and fluid chemistry) close to Rainbow/Logatchev vent systems. Dissolved 13C-bearing alkane species were produced with relatively low H2(aq)/CO2(aq) ratio and the existence of dissolved H2S. Hydroxymethylene is the key intermediate in the hypothesized reaction mechanism, which was consistent with XPS and ToF-SIMS analysis results on the mineral product.