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Geochemical cycles of platinum group elements at the earth surface -Role of anthropogenic and cosmic sources-

地球表面铂族元素的地球化学循环-人为和宇宙源的作用-

基本信息

批准号：
15540466
负责人：
AMAKAWA Hiroshi
金额：
$ 2.05万
依托单位：
The University of Tokyo (2004-2005)Tokyo Metropolitan University (2003)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

My research results are summarized as follows.1. Development of high precision and sensitivity method for determining abundances of platinum group elements in solid samples.I have developed high precision and sensitivity method for determining abundances of platinum group elements (PGE : Ru, Rh, Pd, Os, Ir and Pt) in solid samples by isotope dilution method (for Ru, Pd, Os, Ir and Pt) and external calibration method (only for Rh) using ICP-MS combined with a fire assay preconcentration technique. We applied this method to a standard rock JP-1 issued from the Geological survey of Japan (GSJ). The errors of PGE range 13-25%(2s ; n=5), which are comparable with those by the similar methods combined with chemical separation of PGE. Compared our data with the preferable data proposed by GSJ, the large deviations are observed for Ir. Various evidences indicate that our data are much more reliable than the preferable value.2. Educidation of horizontal transport processes of elements in ocean using the Nd isotopic compositions of seawatersTo elucidate the horizontal transport processes of elements in ocean, I determined the vertical distribution of Nd isotopic compositions at four stations in the Northwest Pacific together with that of surface seawaters at the Northwest Pacific. These results suggest that Nd is involved in the active horizontal transport processes in the surface ocean (above 100-250m).3. Development of high sensitivity method for determining abundances of scandium (Sc) in seawater and its application to marine chemistryTo test Sc as a possible indicator of continentally derived material to the ocean, we developed of high sensitivity method for determining abundances of Sc in seawater. The vertical profile at the station near the Hawaii Islands showed so called "nutrient type" one, which was similar with Y and lanthanides.

我的研究成果总结如下：1。固体样品中铂族元素丰度高精度灵敏测定方法的建立。通过同位素稀释法（Ru, Pd, Os， Ir和Pt）和外部校准法（仅Rh），利用ICP-MS结合火焰测定富集技术，开发了高精度和灵敏度高的固体样品中铂族元素（PGE: Ru, Rh, Pd, Os， Ir和Pt）丰度测定方法。我们将该方法应用于日本地质调查局（GSJ）发布的标准岩石JP-1。PGE的误差范围为13 ~ 25%(2s; n=5)，与同类方法结合化学分离PGE的结果相当。将我们的数据与GSJ提出的优选数据进行比较，发现Ir有较大的偏差。各种证据表明，我们的数据比优选值可靠得多。为了阐明海洋元素水平输运过程，本文测定了西北太平洋4个台站的Nd同位素组成垂直分布以及西北太平洋表层海水的Nd同位素组成垂直分布。这些结果表明，Nd参与了海洋表层（100-250m以上）活跃的水平输运过程。海水中钪（Sc）丰度高灵敏度测定方法的建立及其在海洋化学中的应用为了检验Sc是否可能作为大陆源物质进入海洋的指示物，我们开发了一种测定海水中钪丰度的高灵敏度方法。夏威夷群岛附近站的垂直剖面显示所谓的“营养型”，与Y和镧系元素相似。