单颗粒锆石小束斑LA-ICPMS原位微区U-Pb年龄的测定  

Single zircon in situ U-Pb age by LA-ICPMS at small beam spot

作　　者：彭陆[1] 李全忠[1] 柴发达 闫峻[1] 刘晓强[1] 

机构地区：[1]合肥工业大学资源与环境工程学院,安徽合肥230009

出　　处：《合肥工业大学学报（自然科学版）》2017年第1期110-116,共7页Journal of Hefei University of Technology：Natural Science

基　　金：国家自然科学基金青年科学基金资助项目(40903013)

摘　　要：文章在等离子体中心气流(Ar+He)中加入少量N2,利用激光剥蚀-电感耦合等离子体质谱仪(laser ablation-inductively coupled plasma mass spectrometry,LA-ICPMS)锆石U-Pb测年方法,对91500、Plesovice、Mud Tank及Qinghu 4个锆石标准,在直径24μm小束斑条件下进行了U-Pb年龄测定。测定结果显示:标准锆石91500 36个测试点的^(206)Pb/^(238)U年龄范围为1 053~1 070 Ma,^(206)Pb/^(238)U加权平均年龄为(1 062.3±9.3)Ma(2σ,n=36)。标准锆石Plesovice 40个测试点的^(206)Pb/^(238)U年龄范围为325~345 Ma,206 Pb/238 U加权平均年龄为(337.9±2.8)Ma(2σ,n=40);标准锆石Mud Tank 30个测试点的206 Pb/238 U年龄范围为718~749 Ma,^(206)Pb/^(238)U加权平均年龄为(731.2±8.5)Ma(2σ,n=30);标准锆石Qinghu 30个测试点的^(206)Pb/^(238)U年龄范围为156~164 Ma,^(206)Pb/^(238)U加权平均年龄为(160.0±2.0)Ma(2σ,n=30)。上述结果表明,91500、Plesovice、Mud Tank及Qinghu 4个标准锆石的单点年龄都在误差允许的范围内,其加权平均年龄与推荐值在误差范围内吻合。因此,文中尝试建立的24μm锆石LA-ICPMS U-Pb年龄测试方法设计是可行的,该方法尤其适用于颗粒较小、成因复杂的锆石以较小的激光束斑进行锆石U-Pb年龄的测试。The effects of adding nitrogen to the central gas flow（Ar＋He） of an Ar plasma in laser ablation-in- ductively coupled plasma mass spectrometry（LA-ICPMS） were presented, and LA-ICPMS zircon in-situ anal- ysis technique was used to determine the four standard zircons, including 91500, Plesovice, Mud Tank and Qinghu, at the spot size of 24 μm The results show that zircon standard 91500 zircon 36 test point 206Pb/ 238U age range is between 1 053-1 070 Ma,weighted average 206Pb/238U age is （1 062. 3±9. 3） Ma （2σ,n= 36）; Plesovice 40 test point 206Pb/238U age range is between 325-345 Ma, weighted average 20Pb/238U age is （337. 9±2. 8） Ma （2σ,n=40） ; Mud Tank zircon 30 test point 206Pb/238U age range is between 718-749 Ma, weighted average 206Pb/238U age is （731. 2±8. 5） Ma （2σ,n=30） ; Qinghu zircon 30 test point 206pb/238U age range is between 156-164 Ma,weighted average 206ph/238U age is （160. 0±2. 0） Ma （2σ,n=30）. The results show that four zircons 91500, Plesovice, Mud Tank and Qinghu standard age range are within the error range, the weighted average age and the recommended value are consistent. Try to establish this laboratory of 24 microns and smaller particles zircon LA-ICPMS U-Ph age testing method is feasible, and the method is es- pecially suitable for zircon with smaller particles and complex causes for zircon U-Pb age testing at small laserbeam spot.

关 键 词：小激光束斑 激光剥蚀-电感耦合等离子体质谱(LA-ICPMS) 锆石U-PB年龄 

分 类 号：P597.3[天文地球—地球化学]