橄榄石、单斜辉石和斜方辉石锂、氧同位素原位微区分析标准物质及其微量元素特征  

Olivine,clinopyroxene and orthopyroxene reference materials for Li and O isotope in-situ microanalyses and their trace element compositions

作　　者：王静 苏本勋[1,2,3] 唐国强[2,3,4] 高炳宇 吴石头 李娇[2,4] WANG Jing;SU BenXun;TANG GuoQiang;GAO BingYu;WU ShiTou;LI Jiao(Key Laboratory of Mineral Resources,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;Innovation Academy for Earth Science,Chinese Academy of Sciences,Beijing 100029,China;University of Chinese Academy of Sciences,Beijing 100049,China;State Key Laboratory of Lithospheric Evolution,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China)

机构地区：[1]中国科学院地质与地球物理研究所,中国科学院矿产资源研究重点实验室,北京100029 [2]中国科学院地球科学研究院,北京100029 [3]中国科学院大学,北京100049 [4]中国科学院地质与地球物理研究所,岩石圈演化国家重点实验室,北京100029

出　　处：《岩石学报》2020年第4期1274-1284,共11页Acta Petrologica Sinica

基　　金：国家重点研发计划(2017YFC0601306);中国科学院青年创新促进会(2016067);国家自然科学基金项目(41772055)联合资助.

摘　　要：随着分析技术的发展,锂、氧同位素原位微区分析已成为地球科学研究的重要发展方向。本文介绍了可同时作为锂、氧同位素原位微区分析标准物质的橄榄石(Mg^#=89.6~94.2)、单斜辉石(Mg^#=90~91.9)和斜方辉石(Mg^#=90.1~92.1)的化学组成并对其微量元素进行了报道。三种标准物质的主量成分均一,在其Mg^#值范围内,SIMS氧同位素分析基体效应均不显著,而橄榄石的Mg^#值对SIMS锂同位素分析基体效应为1‰。橄榄石标准物质Ni、Co和Zn含量较高,约为原始地幔值的1~1.5倍;大离子亲石元素和稀土元素含量较低。单斜辉石微量元素中除个别元素外,SN-ICP-MS和LA-ICP-MS的分析结果误差范围内一致,具有成为原位微区分析标准物质的潜力;在原始地幔标准化配分曲线中,V、Sc、Cr和Ga相对其他过渡族元素显著富集;大离子亲石元素Rb和Ba相对Th和U显著亏损,轻稀土相对重稀土元素略富集。斜方辉石过渡族元素Cr、V和Sc接近原始地幔值,大离子亲石元素和轻稀土元素含量较低,在不同仪器分析中误差较大。With the development of analytical techniques,lithium(Li)and oxygen(O)isotope in-situ microanalyses become more important in earth sciences.In this paper,we summarized the chemical compositions of olivine(Mg^#=89.6~94.2),clinopyroxene(Mg^#=90.0~91.9)and orthopyroxene(Mg^#=90.1~92.1)reference materials for both Li and O isotope analyses,and report newly obtained trace elements.The major element contents of these three reference materials are homogeneous.There is no significant matrix effect in the three kinds of reference materials on O isotopes during SIMS analyses,whereas the matrix effect is a linear function of composition,withδ^7Li increasing by 1‰for each mole percent decrease in forsterite component for olivine.The contents of Ni,Co,and Zn in olivine are 1 to 1.5 times as much as the primary mantle,while the contents of large ion lithophile elements and rare earth elements are quite low.The contents of trace elements in clinopyroxene obtained by SN-ICP-MS and LA-ICP-MS are consistent within analytical errors except for a few elements,and thus the clinopyroxene can be the potential reference materials for trace element analysis.They all show enrichment in V,Sc,Cr,and Ga relative to other transition elements in primary mantle-normalized diagrams and significant depletion in large ion lithophile elements Rb and Ba relative to Th and U.The rare earth elements in clinopyroxene are slightly fractionated.The contents of transition elements(Cr,V and Sc)in orthopyroxene are close to that of the primary mantle,whereas the contents of large ion lithophile elements and light rare earth elements are too low to be detected accurately by either LA-ICP-MS or SN-ICP-MS.

关 键 词：标准物质 锂同位素 氧同位素 原位微区分析 基体效应 微量元素 

分 类 号：P597.2[天文地球—地球化学]