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

为了了解地球气候如何响应人类活动的影响而变化，例如化石燃料的燃烧，有必要了解冰期/间冰期气候的自然变化。研究这种变化的方法之一是调查深海沉积记录，其中包括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锗与硅的比例，该比例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来研究海洋沉积物中Ge和Si的分馏，这将创建一个受控的成岩环境，以确定Ge和Si掺入铁羟基氧化物和硫化物中。 此外，将分析现有的孔隙水样品，以调查锗在不同海洋环境中的行为。 将在加州边界地区进行实地研究，以收集更多的孔隙沃茨，并部署原位底栖室来测量不同环境中锗和硅的分馏。

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.