HR: 1340h
AN: PP13A-1026    [Abstracts]
TI: Molybdenum Behavior During Early Diagenesis: Insights from Mo Isotopes
AU: * Poulson, R L
EM: rpoulson@coas.oregonstate.edu
AF: College of Oceanic & Atmospheric Sciences, Oregon State University, 104 Ocean Admin Bldg, Corvallis, OR 97331, United States
AU: Severmann, S
EM: silke.severmann@ucr.edu
AF: Department of Earth Sciences, University of California - Riverside, 2207 Geology Bldg, Riverside, CA 92521, United States
AU: Berelson, W
EM: berelson@usc.edu
AF: Department of Earth Sciences, University of Southern California, 3651 Trousdale Avenue, Los Angeles, CA 90089, United States
AU: McManus, J
EM: mcmanus@coas.oregonstate.edu
AF: College of Oceanic & Atmospheric Sciences, Oregon State University, 104 Ocean Admin Bldg, Corvallis, OR 97331, United States
AB: This study presents Mo isotope data from surface sediments of the California, Mexico, and Peru continental margins. The enriched fraction of Mo in marine sediments can be represented by three primary components: Mn- controlled authigenic Mo, S-controlled authigenic Mo, and Mo associated with organic matter. These three components have distinct Mo isotope compositions and all sediments appear to reflect some mixture of these sources. The primary mechanism of Mo authigenic enrichment at depth for most of these study sites is likely Mo- sulfide precipitation; however, not all sediment profiles converge on a single authigenic isotope signature. Though Mn-associated solid-phase Mo does not typically survive early diagenesis, our data suggest that when Mn reduction is an important source of aqueous Mo within the sediments it is reflected in the isotopic composition of the authigenic Mo-sulfide fraction. While many aspects of Mo geochemical cycling remain poorly constrained, it appears that Mo isotopes may prove a useful proxy for geochemical conditions during sediment deposition.
DE: 4219 Continental shelf and slope processes (3002)
DE: 4825 Geochemistry
DE: 4851 Oxidation/reduction reactions (0471)
DE: 4870 Stable isotopes (0454, 1041)
DE: 4875 Trace elements (0489)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting