An in situ technique for (U-Th-Sm)/He and U-Pb double dating
An in situ technique for (U-Th-Sm)/He and U-Pb double dating
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DOI：
10.1039/c5ja00085h
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发表时间：
2015-01-01
影响因子：
3.4
通讯作者：
Patterson, D. B.
中科院分区：
文献类型：
--
作者：
Evans, N. J.;McInnes, B. I. A.;Patterson, D. B.
本文报道了一种新的激光原位双定年技术，用于矿物的U-Pb和（U-Th-Sm）/He双定年，并将其应用于地质年代学、热年代学和地球化学。原位激光显微分析提供了几个优势，在空间分辨率，生产率和安全性方面，传统的大块晶体的方法。这种新的方法/方法利用了一套可互操作的集成分析仪器，包括193 nm ArF准分子激光系统，四极ICP-MS，四极氦质谱系统和可交换的流通和超高真空分析室。我们描述了锆石分析的分析协议，包括颗粒安装在聚四氟乙烯，参数的父母和女儿的同位素测量，和标准的发展，并提供了一个免费的应用程序确定（U-Th-Sm）/He的“成对”年龄的分析数据。原位双定年方法描述适用于埃伦代尔钾镁煌斑岩管和围岩，西澳大利亚州，并成功地复制了常规的U-Pb和（U-Th-Sm）/He年龄的变化，以前确定的常规技术。
We report on a new laser-based technique for rapid, quantitative and automated in situ double dating (U-Pb and (U-Th-Sm)/He) of minerals, for applications in geochronology, thermochronology and geochemistry. In situ laser microanalysis offers several advantages over conventional bulk crystal methods in terms of spatial resolution, productivity, and safety. This new approach/methodology utilizes an interoperable and integrated suite of analytical instruments including a 193 nm ArF excimer laser system, quadrupole ICP-MS, quadrupole helium mass spectrometry system and swappable flow-through and ultra-high vacuum analytical chambers. We describe the analytical protocols for zircon analysis including grain mounting in Teflon, parameters for parent and daughter isotopic measurement, and standard development, and provide a freeware application for determining (U-Th-Sm)/He 'pairwise' ages from analytical data. The in situ double dating method described is applied to the Ellendale lamproite pipe and country rocks, Western Australia and successfully replicates conventional U-Pb and (U-Th-Sm)/He age variations determined previously by conventional techniques.