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Research on concentrations and isotopic abundances of retractory siderophile elements in Ca, Al-rich inclusions and estimation of chemical and physical conditions of the primitive solar nebula

富Ca、Al包裹体中回缩亲铁元素浓度和同位素丰度研究及原始太阳星云化学物理条件估算

基本信息

批准号：
09640588
负责人：
YONEDA Shigekazu
金额：
$ 2.11万
依托单位：
National Science Museum
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

项目摘要

In order to estimate chemical and physical conditions of the primitive solar nebula, Ca, Al-rich inclusions in the Allende CV3 chondrite were investigated. Methods for quantitative analysis and isotopic ratio measurement of refractory siderophile elements were developed and a search for extinct nuclides was performed.Three Ca, Al-rich inclusions including a lcm-radius spherule were separated from three specimens of the Allende meteorite in the collection of the, National Science Museum A11 of them are coarse-grained inclusions and, from observation using SEM-EDX, one is classified as a Type A inclusion with melilite and spinel ; another inclusion is probably a Type C because of high abundance of anorthite ; the other could be a Type B Using a SIMS at Hiroshima University, Mg-26 excesses due to the extinct nuclideAl-26 were observed in anorthite of the Type C inclusion Also, a trace of the extinct nuclide Cs-135 was detected in an acid-soluble fraction in an H chondriteMethods for quantitative analysis of refractory siderophile elements using an ICP-MS were explored in addition to the well-developed NAA methods. Change of sensitivities of the refractory siderophile elements had to be monitored and severe memory, effects were observed at the measurements of Os. For the negative thermal ionization mass spectrometry of the platinum group elements and other siderophile elements, basic behaviors of formation of negative thermal ions from a mixed solution were investigated in collaboration with Prof. K CJ. Heumann at the University of Mainz Using a Pt single filament method, the intensities of negative thermal ions from the same amount of elements were Re > Os > Ir -- Ru > Mo The Re filament method could be used for better ionization of W and Mo.

为了评价原始太阳星云的化学和物理条件，对阿连德CV 3球粒陨石中的富Ca、Al包体进行了研究。本文介绍了难熔亲铁元素的定量分析和同位素比值测定方法，并进行了绝灭核素的寻找。从国立科学博物馆收藏的三个阿连德陨石样品中分离出三个富含Ca、Al的包裹体，其中包括一个半径为1cm的球状体。其中一个包裹体为A型，含黄长石和尖晶石，另一个包裹体中钙长石含量高，可能为C型;另一种可能是B型。使用广岛大学的西姆斯，在C型包体的钙长石中观察到由于消失的核素Al-26导致的Mg-26过量。此外，本文报道了在一种难溶元素的酸溶组分中检测到痕量的已灭绝核素Cs-135。在铂族元素和其它亲铁元素的负热电离质谱中，与K CJ教授合作研究了混合溶液中负热离子形成的基本行为。Heumann在美因茨大学使用Pt单灯丝方法，来自相同数量的元素的负热离子的强度为Re > Os > Ir-Ru> Mo。Re灯丝方法可以用于更好地电离W和Mo。