Collaborative Studies (USC and UM): Fractionation of Ge and Si during Diagenesis, and its Implications for Regulating the Oceanic Ge/Si Ratio

为了解地球气候如何响应人为影响（如燃烧化石燃料）而发生变化，有必要了解冰期/间冰期气候的自然变率。研究这种变化的一种方法是通过调查深海沉积记录，这些记录包含了过去气候条件的化学、化石和矿物学证据。沉积物中一个潜在的重要信号是蛋白石中Ge与Si的比值，该比值随海洋条件的变化而变化。为了最大限度地利用这一工具，必须充分了解其在海底的化学行为。因此，这项工作将通过实验室实验研究海洋沉积物中Ge和Si的分馏，这将创造一个受控的成岩环境，以确定Ge和Si在铁氧羟基和硫化物中的结合。此外，将分析现有孔隙水样品，以研究Ge在不同海洋环境中的行为。将在加州边境地区进行实地研究，收集额外的孔隙水，并部署原位底栖室，以测量不同环境下Ge和Si的分馏。

To understand how the earth's climate might change in response to anthropogenic influence, such as the burning of fossil fuel, it is necessary to understand the natural variability of climate over glacial/interglacial times. One method of studying this variability is through investigation of the deep-sea sedimentary record, which contains chemical, fossil and mineralogic evidence of past climatic conditions. A potentially important signal in the sediments is the ratio of Ge to Si in opal, which varies in response to changing ocean conditions. To derive the maximum use of this tool, its chemical behavior in the sea floor must be fully understood. Therefore, this work will study the fractionation of Ge and Si in ocean sediments by laboratory experiments that would create a controlled diagenetic setting to determine the incorporation of Ge and Si into iron oxyhydroxices and sulfides. Additionally, existing pore water samples will be analyzed to investigate the behavior of Ge in different ocean settings. Field Studies in the California borderland will be carried out to collect additional pore waters and to deploy in-situ benthic chambers to measure the fractionation Ge and Si in different environments.