| LA-ICP-MS工作参数优化及在锆石U-Pb定年分析中的应用 |
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| 引用本文： | 周亮亮,魏均启,王芳,仇秀梅.LA-ICP-MS工作参数优化及在锆石U-Pb定年分析中的应用[J].岩矿测试,2017,36(4):350-359. |
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| 作者姓名： | 周亮亮 魏均启 王芳 仇秀梅 |
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| 作者单位： | 湖北省地质实验测试中心, 湖北 武汉 430034,湖北省地质实验测试中心, 湖北 武汉 430034,湖北省地质实验测试中心, 湖北 武汉 430034,湖北省地质实验测试中心, 湖北 武汉 430034 |
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| 基金项目： | 湖北省国土资源厅行业科研专项——LA-ICP-MS锆石U-Pb定年技术在鄂东南多金属矿床成因中的应用研究（ETZ2016A12） |
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| 摘 要： | 将激光器(LA)和电感耦合等离子体质谱仪(ICP-MS)联用避免了溶液分析繁琐、耗时的前处理操作,减少了样品制备过程中可能带来的污染,同时又具备分析成本低、测试速度快、分析数据精度高等优势。本文将LA与ICP-MS联接使用,通过激光能量密度和剥蚀频率组合来讨论较低的元素分馏效应,同时匹配RF功率、采样深度、载气及He气流速等主要工作参数以获得较高的元素信号灵敏度和稳定性,从而得到仪器最优工作参数组合,建立了可靠的锆石U-Pb定年方法。通过对锆石标样91500、GJ-1及Ple2ovic互测结果表明,其206Pb/238U加权平均年龄分别为1063.9±6.0 Ma(2σ,n=20)、600.3±2.6 Ma(2σ,n=27)及337.6±1.7 Ma(2σ,n=20),测试结果准确度和精度均在1%范围内,与前人报道的误差范围一致。使用优化后的仪器参数对来自鄂东南铜绿山矿区石英正长闪长玢岩岩体中的实际锆石样品进行测试,获得其206Pb/238U年龄与前人研究结果基本一致,表明本法能准确地对锆石进行定年分析。
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| 关 键 词： | 激光剥蚀电感耦合等离子体质谱 参数优化 元素分馏指数 信号灵敏度 信号稳定性 206Pb/238U加权平均年龄 |
| 收稿时间： | 2017/1/16 0:00:00 |
| 修稿时间： | 2017/7/19 0:00:00 |
Optimizationof the Working Parameters of LA-ICP-MS and Its Application to Zircon U-Pb Dating |
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| ZHOU Liang-liang,WEI Jun-qi,WANG Fang and QIU Xiu-mei.Optimizationof the Working Parameters of LA-ICP-MS and Its Application to Zircon U-Pb Dating[J].Rock and Mineral Analysis,2017,36(4):350-359. |
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| Authors: | ZHOU Liang-liang WEI Jun-qi WANG Fang and QIU Xiu-mei |
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| Institution: | Hubei Research Center for Geoanalysis, Wuhan 430034, China,Hubei Research Center for Geoanalysis, Wuhan 430034, China,Hubei Research Center for Geoanalysis, Wuhan 430034, China and Hubei Research Center for Geoanalysis, Wuhan 430034, China |
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| Abstract: | Laser Ablation (LA) combined with Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) avoids cumbersome analysis of solution and time-consuming pre process and reduces the possible pollution during sample preparation. Moreover, LA-ICP-MS has a few advantages of low cost, rapid determination, and high precision of analysis data. The lower fractionation effect of elements is discussed by combing laser energy density and denudation frequency. Meanwhile, the main working parameters such as RF power, sampling depth, carrier gas and He gas flow rate are matched to obtain high sensitivity and stability of the signal. Based on these, the optimal parameters of the instrument are obtained and reliable zircon U-Pb dating method is established. By mutual determination of zircon age standard substance 91500, GJ-1, and Plešovic, the respective weighted average ages of 206Pb/238U were 1063.9±6.0 Ma (2σ, n=20), 600.3±2.6 Ma (2σ, n=27), and 337.6±1.7 Ma (2σ, n=20). The accuracy and precision are within 1%, consistent with previous studies. Using the optimized parameters of instrument, the quartz-orthoclase diorite porphyrite from the Tonglushan Orefield in Southeast Hubei has the 206Pb/238U age of zirconbasically consistent with the previous results, indicating that this method can be used to zircon U-Pb dating. |
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| Keywords: | Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry parameter optimization element fractionation effect signal sensitivity signal stability 206Pb/238U weighted average age |
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