HR: 0800h
AN: OS51B-09    [Abstracts]
TI: Stable sulfur and carbon isotope investigations of pore-water and solid-phase compounds in sediments of the Chapopote Asphalt Volcano, southern Gulf of Mexico
AU: * Wilhelm, T
EM: thorsten.wilhelm@awi.de
AF: Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, Bremerhaven, 27570, Germany
AU: Bruechert, V
EM: vbrucher@mpi-bremen.de
AF: Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, Bremen, 28359, Germany
AU: Pape, T
EM: tpape@uni-bremen.de
AF: Geosciences Department University of Bremen, Klagenfurter Strasse, 28359, Bremen, Germany
AU: Schubotz, F
EM: fschubotz@uni-bremen.de
AF: Geosciences Department University of Bremen, Klagenfurter Strasse, 28359, Bremen, Germany
AU: Kasten, S
EM: sabine.kasten@awi.de
AF: Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, Bremerhaven, 27570, Germany
AB: During R/V Meteor cruise M67 2a/b (March-April 2006) to the Asphalt Volcanoes of the southern Gulf of Mexico two gravity cores were retrieved from the central depression of the Chapopote Knoll which contained viscous oil/asphalt a few meters below the sediment surface. Also several push cores were taken with the remotely operated vehicle (ROV) QUEST at sites where oil/asphalt reached closely below the sediment surface. From these cores solid-phase and pore-water samples were taken for on-board and subsequent shore-based analyses. Together with a core taken from a background site which is not influenced by asphalt/oil seepage these sediment and pore water samples are currently subject to detailed analyses of (1) the stable sulfur isotopic composition of both dissolved (sulfate and sulfide) and solid-phase (iron monosulfides, pyrite) sulfur compounds, and (2) the composition and stable carbon isotopic signatures of hydrocarbon gases. The major aims of these investigations are to identify whether and to which extent the upward migration of oil, asphalt and gas (1) stimulates biogeochemical processes and turn-over rates, and (2) influences the stable sulfur isotopic signatures of both dissolved and solid phase sulfur compounds. Furthermore, we seek to determine the potential of these - possibly unusual - stable sulfur isotopic signals of solid-phase sulfides to reconstruct hydrocarbon seepage in older geological records and to elucidate how the composition and the stable carbon isotopic signatures of the hydrocarbon gases are altered by the action of typical chemosynthetic communities thriving at these sites.
UR: http:www.rcom.marum.de/Project_E1.html
DE: 1050 Marine geochemistry (4835, 4845, 4850)
DE: 4850 Marine organic chemistry (0470, 1050)
SC: Ocean Sciences [OS]
MN: 2007 Joint Assembly