中国科学院机构知识库网格
Chinese Academy of Sciences Institutional Repositories Grid
Two reliable calibration methods for accurate in situ U-Pb dating of scheelite

文献类型:期刊论文

作者Yanwen Tang; Junjie Han; Tingguang Lan; Jianfeng Gao; Liang Liu; Changhao Xiao; Jiehua Yang
刊名Journal of Analytical Atomic Spectrometry
出版日期2022
卷号37期号:2页码:358-368
DOI10.1039/D1JA00387A
英文摘要

Scheelite is an important metallic mineral in W-related hydrothermal deposits and can be utilized as a reliable geochronometer to directly date the timing of mineralization. Up to now, two previous studies have performed in situ U–Pb dating of scheelite using NIST glasses as reference materials due to the lack of scheelite standards. However, there exists a significant matrix effect between NIST612 and scheelite based on our analysis. Therefore, two reliable calibration methods have been proposed and assessed via LA-SF-ICP-MS in this study. A laser spot size of 32 μm was mainly used to satisfy the signal for 206Pb, 207Pb, and 238U and keep a high resolution to fit small grains and altered crystal zones of scheelite samples. Scheelite WX27 as a secondary standard has been accurately determined in normal ablation settings of 3 J cm−2 – 5 Hz, 3 J cm−2 – 10 Hz, 5 J cm−2 – 5 Hz (using a spot size of 24 μm), 5 J cm−2 – 10 Hz, and 10 J cm−2 – 5 Hz. Its lower intercept 206Pb/238U ages are consistent with each other within error and agree with two known ages (144.8 ± 11.7 and 141.8 ± 5.3 Ma) from the Woxi deposit with age offsets of <3.8%, no matter whether they were calibrated by using concordant wolframite YGX or the combined calibration method (i.e., NIST612 for 207Pb/206Pb and YGX for 238U/206Pb ratios). Moreover, accurate U–Pb ages, ranging from 432 Ma to 92 Ma, were also obtained for five typical W deposits. All these age results demonstrate the reliability of the two calibration methods and indicate that no matrix effect exists between scheelite and wolframite using single spot analysis mode in normal ablation settings. When all the same data from scheelite WX27 were calibrated by using NIST 612, most of the obtained ages were much younger than the known ages, with the age offsets ranging from 5.9% to 18.0%. Thus, NIST glasses are commonly not suitable as primary standards for in situ U–Pb dating of scheelite. Scheelite WX27 contains relatively high U (averaging 7.1 ppm) and low common-lead and is suitable as a candidate reference material for in situ U–Pb dating of scheelite at the moment.

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语种英语
源URL[http://ir.gyig.ac.cn/handle/42920512-1/13631]  
专题地球化学研究所_矿床地球化学国家重点实验室
作者单位1.State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China
2.Laboratory of Dynamic Diagenesis and Metallogenesis, Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China
推荐引用方式
GB/T 7714
Yanwen Tang,Junjie Han,Tingguang Lan,et al. Two reliable calibration methods for accurate in situ U-Pb dating of scheelite[J]. Journal of Analytical Atomic Spectrometry,2022,37(2):358-368.
APA Yanwen Tang.,Junjie Han.,Tingguang Lan.,Jianfeng Gao.,Liang Liu.,...&Jiehua Yang.(2022).Two reliable calibration methods for accurate in situ U-Pb dating of scheelite.Journal of Analytical Atomic Spectrometry,37(2),358-368.
MLA Yanwen Tang,et al."Two reliable calibration methods for accurate in situ U-Pb dating of scheelite".Journal of Analytical Atomic Spectrometry 37.2(2022):358-368.

入库方式: OAI收割

来源:地球化学研究所

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