Geochemical differentiation of terrestrial mantle in view of platinum group elements

铂族元素对地幔的地球化学分异

• 批准号: 04403012
• 负责人: TANAKA Tsuyoshi
• 金额: $ 15.94万
• 依托单位: Nagoya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (A)
• 财政年份: 1992
• 资助国家: 日本
• 起止时间: 1992 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-04403012/
• 关键词: Platinum group elements; Mass spectrometry; Negatively charged ion; Isotope dilution; Osmium; Rhenium; Iridium; Ruthenium

The platinum group elements are considered to reflect a feature of cumulate phase during magmatic differentiation. However, the geochemical behavior of the elements is not known well. The aim of the research is to clarify the geochemical behavior of the elements using an isotope dilution technique. A negative thermal ionization technique using a small and economical quadrupole mass spectrometer is presented. Intense ion beam of negatively charged oxides of Re, Os, Ir and Ru were observed. The principal molecular species produced in this technique are ReO_4^-, OsO_3^-, IrO_2^- and RuO_3^-. The production of these ion species in the distinct mass ranges allows the isotopic analyzes without any chemical separation of these elements each other. For 5ng Os, all Os isotopic ratios were determined with the precision of better than <plus-minus>0.5% except ^<184>Os/^<192>Os because of very low isotopic abundance of ^<184>Os. For 30ng Re, 10ng Ir and 30ng Ru, isotopic measurements were also made with the precision of better than <plus-minus>0.5%. The precision Os the isotopic ratio measurements for Re, Os, Ir and Ru is sufficient for the isotope dilution technique to determine the concentration of these elements in geological samples/ In addition, a iridosmine from Hokkaido was analyzed for Os and Ir by direct loading technique, and ^<187>Os/^<186>Os ratio of 1.0220<plus-minus>0.0089 was obtained.

铂族元素反映了岩浆分异过程中堆积阶段的特征。然而，这些元素的地球化学行为还不是很清楚。研究的目的是利用同位素稀释技术阐明元素的地球化学行为。本文介绍了一种使用小型、经济的四极质谱计的负热电离技术。观察到Re、Os、Ir和Ru的负电荷氧化物的强离子束。该技术产生的主要分子物种为ReO_4^-、OsO_3^-、IrO_2^-和RuO_3^-。这些不同质量范围的离子物质的产生允许同位素分析，而无需这些元素彼此的任何化学分离。对于5 ngOs，由于~（40）Os的同位素丰度很低，除~（40）Os/~（40）Os外，其它各同位素比值的测量精度均优于<plus-minus>0.5%，<184><192><184>对于30 ngRe、10 ngIr和30 ngRu，同位素比值的测量精度也优于<plus-minus>0.5%。用同位素稀释法测定地质样品中Re、Os、Ir和Ru的同位素比值，其精度足以满足地质样品中这些元素的含量测定。此外，还用直接加样法测定了北海道的一种环烯锇矿中Os和Ir的含量，得到的^<187>Os/^<186>Os比值为1.0220 <plus-minus>± 0.0089。

项目成果

田中 剛: "関東地方北東部地球化学図(日本地質アトラス)" 朝倉書店, 18 (1992)

田中刚：《关东地区东北部地球化学图（日本地质图集）》朝仓书店，18（1992）

Shimizu, O.and Tanaka, T.: "Isotope measurement of Re, Os, Ir and Ru by negative thermal ionization mass spectrometry (NTIMS)." Geochemical Journal. (Submitted).

Shimizu, O. 和 Tanaka, T.：“通过负热电离质谱 (NTIMS) 测量 Re、Os、Ir 和 Ru 的同位素。”

Tanaka,T.: "Geochemical survey of the Sanage-yama area in Aichi Prefecture for environmental assesiment" Jour.Earth Planet Sci.Nagoya Univ.41. 1-31 (1994)

田中，T.：“爱知县Sanage-yama地区的地球化学调查以进行环境评估”Jour.Earth Planet Sci.Nagoya Univ.41。

Togoshi,S.: "Trace elenmnts and Nd-Sr isotopes of island are tholeiite from frantal are of NE Japan." Geoclemical Journal. 26. 261-277 (1992)

Togoshi,S.：“岛上的痕量元素和 Nd-Sr 同位素是来自日本东北部扇区的拉斑玄武岩。”

Tanaka, T., Kawabe, I., Hirahara, Y., Iwamori, H., Mimura, K., Sugisaki, R., Asahara, Y., Itoh, T.Yarai, H., Yonezawa, C., Kanda, S., Simizu, O., Hayashi, M., Miura, N., Mutoh, K., Ohta, A., Sugimura, K., Togami, K., Toriumi, T., and Matsumura, Y.: "Geoch

田中，T.，川部，I.，平原，Y.，岩森，H.，三村，K.，杉崎，R.，麻原，Y.，伊藤，T.Yarai，H.，米泽，C.，神田