HR: 0800h
AN: P51D-0968    [Abstracts]
TI: Organic Geochemistry of Hydrothermal Systems on Europa
AU: * Schulte, M
EM: schultemd@missouri.edu
AF: University of Missouri, Dept. of Geological Sciences 101 Geology Building, Columbia, MO 65211 United States
AB: Hydrothermal systems at the water - rock interface, similar to those found at the mid-ocean ridges on Earth, are thought by some to exist at the base of the Europan ocean [1]. In these europan hydrothermal systems, the disequilibria that result from mixing of hydrothermal fluid and europan ocean water favor the abiotic synthesis of organic compounds. The potential for organic compound synthesis depends on the redox state, bulk composition, temperature and pressure conditions, and the extent of water-rock interactions. Although the compositions of both the liquid ocean and the rocky mantle of Europa are unknown, general assumptions are used to estimate the production of organic matter on Europa. Both primitive and more evolved meteorites are considered likely to approximate Europa's rock composition. Carbonaceous chondrites represent the primitive end-member, while the differentiated end-member is represented by basaltic meteorites, such as the eucrites, which are appropriate analogs due to their origination in the outer portions of the asteroid belt in the vicinity of the jovian system. Similarly, a range of compositions must be considered for the liquid water on Europa. Estimates of the fluid chemistry range from brines greater in salinity than terrestrial seawater to more dilute solutions. Geochemical models based on these assumptions and considering a range of water-rock reaction ratios predict that organic compound production is likely to occur in putative Europan sea floor hydrothermal systems. Organic compounds generated in these systems under metastable equilibrium [2,3] are dominated by short-chain alkanes and carboxylic acids. These compounds would be instrumental in the emergence and persistence of life on Europa. References: [1] Kargel J. S. et al. (2000) Icarus 148, 226-265. [2] Seewald J. S. (1994) Nature 370, 285-287. [3] McCollom T. M. et al. (2001) GCA 65, 455-468.
DE: 5215 Origin of life
DE: 5220 Hydrothermal systems and weathering on other planets
DE: 6218 Jovian satellites
DE: 8410 Geochemical modeling (1009, 3610)
DE: 8416 Mid-oceanic ridge processes (1032, 3614)
SC: Planetary Sciences [P]
MN: Fall Meeting 2005