A Collaborative, Biogeochemical Study of the Jurassic Lower Oxford Clay, England

该项目是对下牛津粘土的侏罗纪海相进行详细的同位素生物地球化学研究。其目标是了解沉积微生物过程及其如何影响有机和无机相中碳、氮和硫的保存，以及这些微生物过程与沉积环境之间的关系。将确定特定微生物过程的影响及其普遍存在的环境。对这些岩石中有机硫化合物的分析结果应该会为这些化合物在碳-硫-铁系统中的作用提供新的信息。这项研究的样本是从英格兰中部活跃的采石场收集的。采石场的暴露使人们能够获得这种未成熟的、富含有机碳的泥岩的大量新鲜样本。这些样品代表了所有的地层层位和生物相，是与牛津下粘土的脊椎动物和无脊椎动物古生态专家合作获得的。测量(1)将包括本单位保存完好的广泛生物矿物的碳、氧和硫同位素组成；(2)保存在骨骼和贝壳中的有机物质的碳和氮同位素组成；(3)单个分子化石的丰度和碳同位素组成(即生物标志物)；有机硫化合物和黄铁矿的丰度和硫同位素组成。研究结果应提供独特的农艺信息。

The project is detailed isotopic biogeochemical study of the Jurassic marine Lower Oxford Clay. Its goal is to understand sedimentary microbial processes and how they affect preservation of carbon, nitrogen and sulfur in organic and inorganic phases and the relationship between those microbial processes and depositional environments. Effects of specific microbial processes and the environments in which they are prevalent will be identified. Results of analyses of organic-sulfur compounds in these rocks should provide new information on the role of these compounds in the carbon-sulfur-iron system. Samples for this study were collected from active quarries in central England. The quarry exposures allowed acquisition of large, fresh samples of this immature, organic-carbon-rich mudrock. The samples, representing all stratigraphic horizons and biofacies, were obtained in collaboration with experts on the vertebrate and invertebrate paleoecology of the Lower Oxford Clay. Measurements (i) will include carbon, oxygen and sulfur isotopic compositions of the extensive and well preserved biominerals in this unit; (ii) carbon and nitrogen isotopic compositions of the organic materials preserved in the bones and shells; (iii) abundances and carbon- isotopic compositions of individual molecular fossils (i.e., biomarkers); and (iv) abundances and sulfurisotopic compositions of organic sulfur compounds and pyrite. The results should provide unique taphonomic information.