LA-HR-ICP-MS小束斑锆石U-Pb年龄和微量元素的同时测定  

Simultaneous Determination of U-Pb age and Trace Elements in Zircon by LA-HR-ICP-MS With Small Beam Spot

作　　者：刘瑞萍[1] 李黎 谢胜凯[1] 谭靖[1] 郭冬发[1] LIU Ruiping;LI Li;XIE Shengkai;TAN Jing;GUO Dongfa(Beijing Research Institute of Uranium Geology,Beijing 100029,China)

机构地区：[1]核工业北京地质研究院,北京100029

出　　处：《世界核地质科学》2023年第2期435-443,共9页World Nuclear Geoscience

基　　金：中国核工业地质局铀矿地质项目(编号:2021-22-7);核能开发项目(编号:测HDJS2102);核工业北京地质研究院院长青年科技创新基金项目(编号:测QJ2107)资助。

摘　　要：激光剥蚀电感耦合等离子体质谱(LA-ICP-MS)微区分析技术在同位素、元素含量分析中得到了日益广泛的应用,锆石是该技术最重要的测试对象之一。利用LA-ICP-MS技术,可以实现锆石U-Pb年龄和微量元素含量的同时测定。目前所建立方法的激光束斑直径大部分在20μm以上,为了进一步缩小束斑直径,提高测试空间分辨率,建立适用于小颗粒锆石的原位U-Pb年龄和微量元素同时测定技术,将仪器灵敏度较高的高分辨率电感耦合等离子体质谱(HR-ICP-MS)和193 nm准分子激光器(LA)联用,采用10、16和24μm的束斑直径对标准锆石GJ-1、Plešovice、MUD TANK和Qinghu的U-Pb年龄和微量元素含量进行分析。获得的U-Pb年龄测试相对误差小于1.3%,206Pb/238U年龄测试精度良好,当激光束斑直径为24、16和10μm时,测试精度分别优于1.8%、2.9%和4.9%。微量元素含量结果和稀土元素球粒陨石标准化曲线趋势与已发表数据结果一致。本研究建立的方法所获得的年龄及微量元素含量结果可靠,空间分辨率高,可以为小颗粒锆石样品分析提供技术手段。Laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS)technique is more and more widely used in the analyses of isotope and element content.Zircon is one of the most important test objects of this technique.U-Pb age and trace elements of zircon can be measured simultaneously by LA-ICP-MS method.The present beam spot of laser is more than 20μm.In this paper,high resolution inductively coupled plasma mass spectrometry(HR-ICP-MS)together with 193 nm excimer laser ablation system were used to analyze the U-Pb age and trace element content of GJ-1,Plešovice,MUD TANK and Qinghu standard zircons with laser beam spot diametre of 10,16,24μm.The relative error of U-Pb age is less than 1.3%.The analytical precision 206Pb/238U age is good,and the precision is within 1.8%,2.9%and 4.9%respectively when the laser beam spot diameter is 24,16,10μm.The analyzed results of trace element and chondrite-normalized rare earth element patterns are consisitent with the published data.Therefore,the U-Pb age and trace element contents acquired by the method esbablished in this study are reliable,and the method can provide technical mean for small zircon grains with high spatical resolution.

关 键 词：锆石 LA-HR-ICP-MS U-PB年龄 微量元素 

分 类 号：P597[天文地球—地球化学]