The chemical and isotopic studies on the genethis and evolution of the lunar highland materials.

月球高地物质起源和演化的化学和同位素研究。

• 批准号: 11640492
• 负责人: TAKAHASHI Kazuya
• 金额: $ 1.79万
• 依托单位: RIKEN
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11640492/
• 关键词: lunar samples; surface materials; trace elements; water-rock interaction; Accelerator mass spectrometry; 微量元素; 岩石-水相互作用; 隕石; 質量分析; 年代測定; 化学分析; 宇宙線生成核種

(1) On the lunar surface, a possibility of the existence of water has been supposed. Therefore, we examined the water-rock interaction, based on the viewpoints of affection by alkaline and aikaline-earth elements on the dissolution process of silicate materials. We showed that the alkaline-earth cations, cspecially Ca^<2+> and Sr^<2+>, promoted the dissolution of silicate and stabilized the dissolved species of silicates. Alkaline-earth elements have been known to be enriched in the lunar surfacc materials and that observation is considered to be important to examine the interaction betwoen water and lunar surface materials.(2) A Iunar meteorite. Asnka-881757 is a new type of mcteorites distinct from Apollo samples. This meteorite gabbroic feature with the age of 3.8 billion years and has been coneidered to reflect old lunar evolution. Thc REE abundances shows a typical cumulate type, as it were "solid type", pattcrn. This implies that lunar gabbro, Asuka-881757, represents the carlier-stage cumulate for the primary lunar magma.(3) The quantitativo analyses of cosmogenic nuclides, such as <-26>^Al or <41>^Ca, make it possible to develop the studies on the history of surface planetary materials. We have developed the new analytical system which consists of ECR (electron cyc.lotron rosonance) ion source and heavy ion linear accelerator. Using this system, we succesefully analysed many trace elemente in several kinds of samples with the detoction limits around 10^<-12>without any sample preparations. Using the technique of full atripping by the high energy acceleration up to 6 MeV/u, <26>^Al-<26>^Mg separation has been achieved to detect <26>^Al with high sensitivity.

(1)在月球表面，曾推测有水存在的可能性。因此，我们从碱性元素和碱土元素对硅酸盐材料溶解过程的影响的观点出发，考察了水-岩相互作用。结果表明，碱土阳离子，特别是Ca~(2+)和La~(2+)，促进了硅酸盐的溶解，稳定了硅酸盐的溶解形态。已知碱土元素在月球表面物质中富含，这种观测被认为是研究水与月球表面物质相互作用的重要手段。(2)月球陨石。Asnka-881757是有别于阿波罗样品的一种新类型的闪长岩。这块陨石辉长岩的年龄为38亿年，被认为反映了古老的月球演化。稀土元素丰度呈典型的堆积型，为“固体型”模式。这意味着月球辉长岩Asuka-881757代表了原始月球岩浆的卡利尔期堆积。(3)宇宙成因核素的定量分析，如&lt；-26&gt；^Al或&lt；41&gt；^Ca，为开展表面行星物质史的研究提供了可能。我们研制了由ECR(电子回旋共振)离子源和重离子直线加速器组成的分析系统。利用该系统，我们在不需要任何样品制备的情况下，成功地分析了几种样品中的多种痕量元素，检出限在10^~(-12)~(-1)左右。利用高达6 MeV/u的高能加速全加速技术，实现了~lt；26&Al；~(26)Mg的高灵敏度检测。

项目成果

M.Kidera, K.Takahashi et al.: "Development of new analytical system using the ECR ion source and heavy ion liniac"Aanalytical Sciences. (In press). (2002)

M.Kidera、K.Takahashi 等人：“使用 ECR 离子源和重离子直线加速器开发新的分析系统”分析科学。