Molybdenum Isotope Geochemistry in Marine Sediments

Oregon State University, Corvallis OR

Investigators

Abstract

ABSTRACT OCE-0219651 A PI from Oregon State University plans to test the hypothesis that during authigenic uptake Mo isotopes are fractionated with the lighter isotopes being preferentially taken up relative to the heavy isotopes leaving behind a residual (dissolved) Mo pool that is isotopically heavy relative to seawater. To prove the hypothesis, the PI will analyze existing near surface (top 20 cm) porewater and sediment samples from the Peru/Chile margin and the California margin for 98Mo and 95Mo to assess the early diagenetic behavior of Mo. In addition, a cruise is planned to the Santa Barbara Basin, CA, to collect and analyze deeper sediment and porewater samples from a region where sediments are exposed to continuously changing redox conditions. Results from these samples will determine under what conditions molybdenum isotopes fractionate and whether this fractionation is preserved in the sedimentary record. This information will help determine whether this isotope can be used as a proxy for identifying reducing conditions in sediments.