| 岩石样品中低含量铂族元素和锇同位素比值的高精度测量方法 |
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| 引用本文： | 杨竞红 GerharBRUGMANN 等.岩石样品中低含量铂族元素和锇同位素比值的高精度测量方法[J].岩石学报,2001,17(2):325-331. |
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| 作者姓名： | 杨竞红 GerharBRUGMANN |
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| 作者单位： | 1. 内生金属成矿机制研究国家重点实验室,南京大学地球科学系,南京210093
2. Max-Planck Institute of Chemistry,Mainz 55020,Germany |
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| 基金项目： | 本文受国家杰出青年科学基金项目(编号:49925306)和国家重点基础研究项目(G1999043208)资助. |
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| 摘 要： | 铂族元素（Os,Ir,Pt,Ru,Rh,Pd)具有强亲铁性和强亲铜性，为一组地球化学性质相近的相容元素，铂族元素包含两个同位素衰变体系（^190Pt-^186Os和^187Re-^187Os)。近年来，铂族元素和Re-Os同位素在研究各类不同地持作用过程中，尤其是在地幔岩石的研究中，作用独特，效果显著。由于地幔岩石的铂族元素含量较低，因此高精度，高灵敏度的分析测试方法的研究就显得十分重要。以往的分析方法（如常规的ICP－MS和中子活化分析方法），对含10^-9-10^012级低含量铂族元素的产品分析精度一般较差（＞15％－100％）。所采用的分析流程通常也无法同时获得样品的铂族元素含量和Os同位素比值。本文采用新的熔样方法（HAP－S高温高压釜酸溶法），新的化学流程（溶剂萃取和阴离子交换树脂柱）和新的分析仪器（多接收等离子体质谱MC－ICPMS和负离子热电离质谱N－TIMS）。用同位素稀释法对低含量地幔橄榄岩样品同时测定的铂族元素含量和Os同位素比值，获得了高精度的分析结果。对所分析的地橄榄样品中的铂族元素分配曲线和Os同位素组成的地质意义进行了初步探讨。
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| 关 键 词： | 铂族元素 锇同位素 MC－ICPMS N－TIMS 地幔岩石 橄榄岩 同位素稀释法 |
| 修稿时间： | 2000年9月10日 |
Precise determination of the platinum-group elements and Os isotopic ratios in
low-level rock samples. |
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| Gerhard BR.Precise determination of the platinum-group elements and Os isotopic ratios in
low-level rock samples.[J].Acta Petrologica Sinica,2001,17(2):325-331. |
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| Authors: | Gerhard BR |
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| Abstract: | The platinum group elements (Os, Ir, Pt, Ru, Rh, and Pd) are highly siderophile and chalcophile elements, which are compatible elements and show similar geochemical behaviours. This group of elements includes two radiogenic isotope decay systems of 190 Pt 186 Os and 187 Re 187 Os. Recently, the application of PGEs and Re Os isotope systems in the study of various geological processes, especially in mantle rocks study, has achieved great success and proven to be a useful geochemical tool. Due to the general low concentrations of the PGEs in mantle rocks, it is crucial to develop an analytical method with high precision and high sensitivity. Previous analytical methods such as conventional ICP MS and INAA usually give low analytical precision of >15 to 100% for sub ppb to ppt level rock samples. In addition, the analyses of PGEs and Os isotopic compositions are completed separately using different chemical separation schemes. In this paper, we report a new method that can obtain high precision results for both the PGEs concentrations and the Os isotopic compositions in one aliquot of low level mantle rock samples, using a new sample digestion apparatus (HPA S) and a modified chemical separation method with solvent extraction and anion exchange resins. The PGEs concentrations and Os isotopic ratios of a set of mantle peridotites are measured by MC ICPMS and N TIMS, respectively, and their geological significances are briefly discussed. |
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| Keywords: | PGEs Os isotopes MC ICPMS N TIMS Mantle rocks |
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