U.S.-France Cooperative Research: Oxygen and Hydrogen Isotope Geochemistry of Laterites

这项为期两年的奖项支持美法合作研究，涉及凯斯西部保护区的塞缪尔·萨文和让-皮埃尔·吉拉德，以及艾克斯-马赛第三大学的丹尼尔·纳洪。研究人员建议将同位素技术应用于红土的研究，红土是覆盖地球大部分地区的热带土壤。他们合作的目标包括分析在巴西发现的具有良好特征的活跃红土中矿物的氧和氢比例。Savin博士和Girard博士将他们在低温地质材料中粘土和相关矿物的稳定同位素研究方面的丰富经验带到了合作中。此外，这位法国研究员在土壤成因和红土风化的地球化学问题上的专业知识也起到了补充作用。他们将联合收集在巴西亚马逊盆地发现的红土样本，并进行实验室分析。红土为获取古代气候信息提供了最好的前景之一。利用稳定同位素研究，研究人员建议确定红土矿物含量中记录的古温度和古代降雨的同位素值。这一结果对于研究利用稳定同位素重建古气候具有重要意义。了解这些古老的气候因素，特别是热带地区的降雨，将有助于我们理解赤道降雨模式的变化与全球气候变化之间的联系。

This two-year award supports U.S.-France cooperative research involving Samuel Savin and Jean-Pierre Girard of Case Western Reserve and Daniel Nahon of the University of Aix-Marseille III. The investigators propose to apply isotopic techniques to the study of laterites, which are tropical soils that cover a substantial portion of the earth. The objectives of their cooperation involve analyzing oxygen and hydrogen ratios of minerals in well-characterized, active laterites found in Brazil. Drs. Savin and Girard bring to the collaboration their extensive experience in stable isotope studies of clays and related minerals in geologic materials of low temperature origin. This is complemented by the French investigator's expertise in problems of soil genesis and geochemistry of laterite weathering. They will jointly collect laterite samples found in the Amazon Basin in Brazil and conduct laboratory analysis. Laterites offer one of the best prospects to obtain information about ancient climates. Using stable isotopes studies, the investigators propose to determine both paleotemperatures and isotopic values of ancient rainfall as recorded in the mineral content of the laterites. The results will be important to research into the use of stable isotopes for paleoclimatic reconstructions. Knowledge about these ancient climatic factors particularly rainfall in tropical regions will advance our understanding of the link between change in equatorial rainfall patterns and global climate change.