Concurrent Determination of U-Pb Age and REE Mass Fractions of Zircon by High Mass Resolution SIMS
Concurrent Determination of U-Pb Age and REE Mass Fractions of Zircon by High Mass Resolution SIMS
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高质量分辨率 SIMS 同时测定锆石的 U-Pb 年龄和 REE 质量分数
DOI：
10.1111/ggr.12344
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发表时间：
2020
影响因子：
3.8
通讯作者：
Li Xian-Hua
中科院分区：
文献类型：
--
作者：
Liu Yu;Li Qiu-Li;Tang Guo-Qiang;Li Xian-Hua
对同一区域的锆石进行年代学和地球化学联合研究，提供了有关时间和成因的宝贵信息，特别是在多生长变质锆石的情况下。采用多接收器二次离子质谱仪（西姆斯），在8 μm尺度上成功实现了锆石U-Pb年龄和稀土元素含量的高空间分辨率同步分析方法。采用了特殊的仪器参数，包括应用约15000的高质量分辨率以取代先前的能量过滤器方法，以及用于将每次分析的测量时间缩短至18分钟的动态多收集器模式。六个锆石标准物质获得了精确的206 Pb/238 U年龄，与普通的单收集器方法相当，但空间分辨率高出2-3倍。本研究中测量的所有锆石颗粒均显示出富集的重稀土元素（HREE）含量，与先前报道的LA和溶液ICP-MS方法测定的值一致。在这项研究中，使用西姆斯和LA-ICP-MS方法测量的轻稀土（LREE）质量分数，尽管体积相当不同，但在不确定性范围内显示出一致的结果。
A combined geochronological and geochemical investigation for the same domain of zircon provides valuable information on timing and genesis, particularly in the case of multi‐growth metamorphic zircon. A high spatial resolution concurrent analytical method for zircon U‐Pb age and rare earth element content was successfully achieved in this study, using a multi‐collector secondary ion mass spectrometer (SIMS) at a ~ 8 μm diameter scale. Special instrument parameters were employed, including a high mass resolution of approximately 15000 applied to replace the previous energy filter method, and a dynamic multi‐collector mode used to reduce the measurement time to 18 min per analysis. Six zircon reference materials yielded precise and accurate206Pb/238U ages, which are comparable to those obtained by the ordinary mono‐collector method, but with 2–3 times higher spatial resolution. All zircon grains measured in this study showed enriched heavy‐REE (HREE) contents consistent with previously reported values determined by LA and solution ICP‐MS methods. The light‐REE (LREE) mass fractions measured using both SIMS and LA‐ICP‐MS methods in this study, although with quite different volume, show consistent results within uncertainties.