Geochemistry of marine sediments

沉积在海底的沉积物是一系列时间尺度上海洋学和气候变化的自然档案。这些变化需要有充分的文件记录，并查明其原因，以便能够对气候和环境变化模型进行测试，并对未来的气候变化作出预测。我的研究涉及从海底回收的沉积物岩心的化学和同位素特性中构建过去海洋学和大气变化的记录。这些特性可用作沉积物积累时海洋中特定条件的指标。例如，我们能够确定沉积物颗粒的来源和颗粒在海底的运输方式、核心地点上覆的海洋表面沃茨的生产力、表面沃茨的温度、底层水的氧合、海洋和大气中二氧化碳的丰度以及过去浮游植物养分利用的程度。所有这些信息可以组合在一起，得出地球历史上以前海洋状态的图片，这可以用来找出海洋如何影响大气，以及如何受到大气的影响。这项申请要求支持研究赤道东太平洋的古海洋学，热带和极地地区海洋和大气变化之间的联系，以及应用这些方法发现古代富含有机物的沉积岩的可能形成模式。

The sediments accumulating on the sea-floor represent natural archives of oceanographic and climatic changes over a range of time-scales. Such changes need to be fully documented, and their causes identified, so that tests can be made of models of climate and environmental change, and predictions of future climate variations can be formulated. My research involves the construction of records of past oceanographic and atmospheric changes from the chemical and isotopic properties of cores of sediments recovered from the sea floor. Such properties can be used as indices of particular conditions in the ocean at the time the sediment was accumulating. For example, we are able to determine the sources of the sediment particles and the mode of transport of the particles on the sea floor, the productivity of the surface waters of the ocean overlying the core site, the temperature of the surface waters, bottom water oxygenation, the abundance of CO2 in the ocean and in the atmosphere, and the extent of phytoplankton nutrient utilization in the past. All of these pieces of information can be fitted together to arrive at a picture of the state of the ocean at previous times in Earth's history, and this can be used to find out how the ocean influences, and is influenced by, the atmosphere. This application requests support for studies of the palaeoceanography of the eastern equatorial Pacific, linkages between oceanic and atmospheric changes in the tropics and the polar regions, and the application of these approaches to discovering the possible modes of formation of ancient organic-rich sedimentary rocks.