Collaborative Research (OSU and USC): Evaluating the Utility of Germanium Isotopes as a Paleoproxy

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ABSTRACTOCE-0326574OCE-0326575Records of oceanic Ge:Si preserved in diatoms show temporal variations that reflect changes in the marine Si cycle through time. The variations may be influenced by changes in the ratio of weathering to hydrothermal inputs, changes in the relative rates of Ge removal in opal versus non-opal phases or by changes in the internal cycling of Si in the ocean and the fractionation of Ge:Si by diatoms. A scientist from Oregon State University and one from the University of Southern California will investigate the utility of germanium isotopes as a geochemical tracer to provide a constraint to distinguish amongst the influences of the above mentioned factors. To attain this goal, the PIs plan to analyze samples from rivers, geothermal fluids, sediment pore waters and diatoms to assess whether there is Ge isotope fractionation during low-temperature weathering, in high-temperature geothermal systems, during diagenesis and during diatom uptake, respectively. It is anticipated that results from this study will show that Ge isotopes can be used to distinguish the relative rates of weathering and hydrothermal fluid flow.