The study is funded for the development of Th-230 profiling in deep-sea sediments as a paleoceanographic tool. The first bjective of the research is to complete a survey of Th-flux in the deep sea based on sediment-trap samples. Results will be used to determine the extent to which Th-flux varies with particle flux on an ocean-wide scale. The second objective is to measure detailed detailed profiles of excess Th-230 in deep-sea sediment cores. The profiles will be interpreted with a model that assumes a known rain rate of thorium-230 to the seafloor, to construct records of biogenic calcium carbonate production and dissolution rates. The focus will be on variations that accompained the last deglaciation, and the records will be used to test models which seek to explain the increase in atmospheric carbon dioxide that occurred at that time.
