锆石LA-ICP-MS原位微区U-Pb定年及微量元素的同时测定  

In Situ U-Pb Dating and Trace Element Simultaneity Determination of Zircon by LA-ICP-MS

作　　者：王岚[1,2] 杨理勤[1] 王亚平[3] 张勇[1] 陈雪[1] 冯亮[1] 陈占生[1] 

机构地区：[1]中国人民武装警察部队黄金地质研究所,河北廊坊065000 [2]中国地质大学(北京)科学研究院,北京100083 [3]国家地质实验测试中心,北京100037

出　　处：《地球学报》2012年第5期763-772,共10页Acta Geoscientica Sinica

基　　金：中国人民武装警察部队黄金指挥部博士后科研基金(编号:WH12-02);黄金专项(编号:HKY2012-04)联合资助

摘　　要：利用配有的New Wave213nm激光和ThermoFisher X Series2四极杆等离子体质谱,对年龄在158～1065Ma之间的5个标准锆石进行了U-Pb同位素和微量元素的同时测定。测定结果显示,在激光频率为10Hz,斑束直径为30μm下,91500、GJ-1、TEMORA-1、Pleovice和Qinghu标准锆石所获得的加权平均年龄分别为(1059±11)Ma(2σ,n=21),(604.4±4.7)Ma(2σ,n=25),(419.3±3.4)Ma(2σ,n=14),(338.7±2.4)Ma(2σ,n=23)和(158.9±1.7)Ma(2σ,n=18),年龄分析测定的单点相对偏差(2σ)均小于5.6%,加权平均年龄的相对偏差(2σ)均小于1.08%。5个标准锆石定年结果在误差范围内与前人报道的年龄值完全一致。在相同的测试条件下,以NIST610为外标,对上述标准锆石的微量元素进行了同时测定,Pleovice除了Nb比文献给定的值偏高外,其余微量元素和91500微量元素的测定结果都落在文献报道的范围之内,GJ-1中的Pb、Th和U落在TIMS测定值的范围之内,TEMORA-1中的Th和U落在SHRIMP测定的值之内,Qinghu中的Th和U落在SIMS测定的值之内。从5个标准锆石的稀土元素球粒陨石标准化曲线可看出,所获得的稀土元素的相对含量也准确。Various reference zircons 158-1060 Ma in age and trace elements were analyzed simultaneously using New Wave 213 nm laser ablation inductively coupled plasma-mass spectrometry （LA-ICP-MS）.The results showed that the weighted average ages of 91500,GJ-1,TEMORA-1,Ple ovice and Qinghu standard zircons were （1059±11） Ma （2σ,n=21）,（604.4±4.7） Ma （2σ,n=25）,（419.3±3.4） Ma （2σ,n=14）,（338.7±2.4） Ma （2σ,n=23） and （158.9±1.7） Ma （2σ,n=18） respectively when the laser frequency was 10 Hz and laser ablation spot size was 30 μm.The relative errors （2σ） of a single point of age were all smaller than 5.6%,and the relative deviation （2σ） of weighted average age were all smaller than 1.08%.The results agree with the ID-TIMS and SHRIMP data reported previously.Using NIST 610 as the reference material and 29 Si as the internal calibrate,the authors analyzed twenty trace and rare earth elements for these reference zircons under the same test condition.All the other trace elements and the trace elements results of 91500 fall within the range of the reported literature except Nb in Ple ovice which is higher than the reported value.Pb,Th and U of GJ-1 all fall in the region of reported TIMS data,while Th and U of TEMORA-1 fall within the range of reported SHRIMP data,and Th and U of Qinghu fall within the range of reported SIMS data.Chondrite-normalized REE distribution curves of these standard zircons show that the relative content of rare earth elements obtained is accurate.

关 键 词：LA-ICP-MS 锆石 U-PB定年 微量元素 

分 类 号：P597[天文地球—地球化学] P595[天文地球—地质学]