热电离质谱计测定国家标准火成岩粉末Sr-Nd-Pb同位素组成  

Sr-Nd-Pb Isotopic Composition of the Chinese National Standard Igneous Rock Powders Measured by the Thermal Ionization Mass Spectrometry

作　　者：王智毅 程泓 赵静欣 叶日胜 李为用 贺剑峰[1] 陈福坤[1] WANG Zhiyi;CHENG Hong;ZHAO Jingxin;YE Risheng;LI Weiyong;HE Jianfeng;CHEN Fukun(School of Earth and Space Sciences,University of Science and Technology of China,Hefei 230026,China)

机构地区：[1]中国科学技术大学地球和空间科学学院,合肥230026

出　　处：《高校地质学报》2023年第5期679-692,共14页Geological Journal of China Universities

基　　金：国家自然科学基金(42172051,41872049)资助。

摘　　要：文章以美国地质调查局制备的标准岩石粉末(BCR-2玄武岩、BHVO-2玄武岩、AGV-2安山岩)作为参考物质,运用同位素稀释法和热电离质谱计同位素比值测量方法,分析中国三种火成岩标准粉末(GSR-1花岗岩、GSR-2安山岩、GSR-3玄武岩)Sr-Nd-Pb同位素组成,观察其同位素组成及均一性特征。分析结果表明:这三种火成岩岩石标准粉末都具有均一的Sr和Nd同位素组成;相比GSR-1花岗岩,GSR-2安山岩和GSR-3玄武岩的Pb同位素组成相对均一。GSR-1花岗岩的Pb同位素组成有较大的变化范围,不均一性特征可能受高U和高Th矿物的放射性成因Pb同位素组成叠加影响。根据测量结果,作者认为三种国家火成岩标准粉末适合作为Sr和Nd同位素组成分析的参考物质,GSR-2安山岩和GSR-3玄武岩也是理想的Pb同位素组成分析的参考物质。In this study,Sr-Nd-Pb isotopic compositions of three Chinese national igneous rock standard materials,GSR-1 granite,GSR-2 andesite,and GSR-3 basalt,were measured by means of the techniques of the isotopic dilution and the thermal ionization mass spectrometry,to investigate the homogeneity of their isotopic compositions and the suitability for the usage as rock standard materials.Three international rock standard materials,BCR-2 basalt,BHVO-2 basalt,and AGV-2 andesite,produced by the US Geological Survey,were simultaneously analyzed as reference materials to check the reliability of the analytical procedures.The analytical results show that three national standard materials of igneous rocks have homogeneous Sr and Nd isotopic compositions.Compared to the GSR-1 granite,the GSR-2 andesite and GSR-3 basalt yield homogeneous Pb isotopic compositions.Relatively large variation in Pb isotopic composition of the GSR-1 granite might be caused by the addition of radiogenic Pb isotopes from those minerals having high U and Th contents.On the basis of the analytical results reported in this study,it is suggested that the three national standard materials of igneous rock powders are suitable as the reference materials for the Sr and Nd isotopic measurements and,the GSR-2 andesite GSR-3 basalt are also the ideal candidates as reference materials for the Pb isotopic analysis.

关 键 词：标准岩石粉末 GSR-1花岗岩 GSR-2安山岩 GSR-3玄武岩 SR-ND-PB同位素 

分 类 号：P599[天文地球—地球化学]