10 μm尺度锆石U-Pb年龄的LA-MC-ICP-MS测定 |
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引用本文:耿建珍,张健,李怀坤,李惠民,张永清,郝爽.2012.10 μm尺度锆石U-Pb年龄的LA-MC-ICP-MS测定[J].地球学报,33(6):877-884. |
DOI:10.3975/cagsb.2012.06.05 |
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基金项目:国土资源部公益性行业科研专项“非锆石类富铀矿物U-Pb同位素定年方法研究”(编号: 200911043-15) |
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中文摘要:利用激光烧蚀多接收器等离子质谱系统, 采用离子计数器与法拉第接收器同时接收U-Pb同位素的技术, 对4个标准锆石GJ-1, 91500, M257和TEMORA采用10 μm剥蚀斑直径、单点剥蚀模式测定, 得到了(602±3) Ma (n=32)、(1058±3) Ma (n=29)、(561.9±2.5) Ma (n=32)和(414.7±2.3) Ma (n=36)的结果; 对GJ-1和TEMORA采用5 μm剥蚀斑直径、曲线扫描模式测定, 得到(596.9±4.5) Ma (n=22)、(417.9±2.5) Ma (n=32)的年龄, 均与文献参考值在误差范围内一致。10 μm斑径单点剥蚀得到I9801、05SD07-01两个典型变质锆石年龄分别为(426±2) Ma (n=30)、(1815±10) Ma (n=16), 5 μm斑径曲线扫描得到I9801、05SD07-01年龄分别为(427±3) Ma (n=32)、(1789±32) Ma (n=15), 均为其可信年龄结果。利用LA-MC-ICP-MS系统对小颗粒锆石、锆石变质增生边或其他成因增生边进行10 μm尺度内U-Pb定年是可行的。 |
中文关键词:LA-MC-ICP-MS 离子计数器 锆石U-Pb定年 10 μm尺度锆石 |
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Ten-micron-sized Zircon U-Pb Dating Using LA-MC-ICP-MS |
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Abstract:A method of in situ U-Pb dating of 10-micron-sized zircons using LA-MC-ICP-MS is reported in this paper. All the U-Pb isotopes were simultaneously collected by the ion counters and the farday cups. Four international zircon standards (GJ-1, 91500, M257 and Temora) and two metamorphic zircon samples (I9801 and 05SD07) were measured. The weighted mean U-Pb ages of GJ-1, 91500, M257 and Temora obtained in 10 μm single spot ablasion model are (602±3) Ma (n=32), (1058±3) Ma (n = 29), (561.9±2.5) Ma (n=32) and (414.7±2.3) Ma (n=36), whereas the mean ages of GJ-1 and Temora are (596.9±4.5) Ma (n=22) and (417.9±2.5) Ma (n=32) in 5 μm curve ablasion model. The results are in excellent agreement with the previously reported data. The U-Pb ages of I9801 and 05SD07 are (426±2) Ma (n=30) and (1815±10) Ma (n=16) in 10 μm single spot ablasion model, (427±3) Ma (n=32) and (1789±32) Ma (n=15) in 5 μm curve ablasion model; the results are credible and consistent with SHRIMP dating results. Hence it is feasible to carry out 10-micron-sized zircon U-Pb dating using LA-MC-ICP-MS. |
keywords:LA-MC-ICP-MS ion counter U-Pb dating 10-micron-sized zircons |
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