Isotopic Geochemistry of Oceanic Mantle Sections and the Dating of Quaternary Volcanics

建议开展：1）深入开展同位素研究 Re-Os、Sm-Nd、Rb-Sr系和铂的地球化学 基性和超镁铁质岩石中的族元素， 研究地幔源区、分异产物及其 230 Th的应用， 其他中间子的U和Th衰变系列的 全新世和晚更新世火山岩的年代测定， 这些火山岩与岩浆源的关系以及 斑晶的形成。 除了手头的样本， 将进行工作，以获得非常新鲜的材料， 地点。 这些问题将在三年内得到解决 使用新开发的质谱技术， 铂族负热离子质谱 元素和新一代高丰度灵敏度质量 光谱仪（丰度灵敏度优于5 x 10-10， AMU）具有高传输。 最近开发的分析 化学程序将用于在超低 有效地降低浓度，污染可忽略不计。 这项工作应导致对新的科学认识 研究岩石的起源，以及 改进分析技术。

This proposal is to conduct: 1) an in depth study of the isotopic geochemistry of the Re-Os, Sm-Nd and Rb-Sr systems and of platinum group elements in basic and ultramafic rocks for the purpose of studying mantle sources, their differentiation products,and their evolution over the Phanerozoic; and 2) the application of 230Th and other intermediate daughters of the U and Th decay series to the dating of Holocene and late Pleistocene volcanics and the relationship of these volcanics to magma sources and the times of formation of phenocrysts. In addition to samples at hand, filed work will be conducted to obtain very fresh materials at key localities. These problems will be attacked over a three-year period, using newly developed mass spectrometric techniques of negative thermal ion mass spectrometry of the platinum group elements and a new generation high abundance sensitivity mass spectrometer (abundance sensitivity better than 5 x 10-10 for 2 amu) with high transmission. Recently developed analytical chemical procedures will be used to separate elements at ultra low level concentrations efficiently and with negligible contamination. This work should result in new scientific understanding on the origins of the rocks to be studied, as well as the development of improved analytical techniques.