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

为了了解地球气候可能如何应对人为影响，例如化石燃料的燃烧，有必要了解冰川/间冰期气候的自然变异性。研究这种变化的一种方法是调查深海沉积记录，其中包含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的比率，这一比率会随着海洋条件的变化而变化。为了最大限度地利用这种工具，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，这些实验将创造一个受控的成岩环境，以确定Ge和Si在氢氧化铁和硫化物中的结合情况。此外，将对现有的孔隙水样本进行分析，以调查不同海洋环境中Ge的行为。将在加州边界进行实地研究，以收集更多的孔隙水，并部署就地海底暗室，以测量不同环境中的分馏Ge和Si。

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.