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

保存在硅藻中的海洋Ge：Si的记录显示了反映海洋硅随时间循环的变化的时间变化。这种变化可能受风化作用与热液输入之比的变化、蛋白石相与非蛋白石相中Ge去除相对速率的变化、海洋中硅的内部循环变化以及硅藻对Ge：Si的分馏作用的影响。俄勒冈州立大学的一名科学家和南加州大学的一名科学家将调查锗同位素作为地球化学示踪剂的用途，以提供区分上述因素影响的约束。为实现这一目标，PIS计划分析来自河流、地热流体、沉积物孔隙水和硅藻的样品，以评估在低温风化、高温地热系统、成岩作用和硅藻吸收过程中是否存在Ge同位素分馏。预计这项研究的结果将表明，Ge同位素可用于区分风化和热液流动的相对速率。

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.