王利玲, 张树明, 许迅, 张鑫, 阮小语, 蓝德初, 吴志春, 戚佳伟. 2020: 江西相山矿田北部产铀花岗斑岩LA-ICP-MS锆石U-Pb定年及成因类型. 地质通报, 39(1): 62-79.
    引用本文: 王利玲, 张树明, 许迅, 张鑫, 阮小语, 蓝德初, 吴志春, 戚佳伟. 2020: 江西相山矿田北部产铀花岗斑岩LA-ICP-MS锆石U-Pb定年及成因类型. 地质通报, 39(1): 62-79.
    WANG Liling, ZHANG Shuming, XU Xun, ZHANG Xin, RUAN Xiaoyu, LAN Dechu, WU Zhichun, QI Jiawei. 2020: LA-ICP-MS zircon U-Pb dating and genetic types of uranium-bearing granite porphyry in northern Xiangshan orefield, Jiangxi Province. Geological Bulletin of China, 39(1): 62-79.
    Citation: WANG Liling, ZHANG Shuming, XU Xun, ZHANG Xin, RUAN Xiaoyu, LAN Dechu, WU Zhichun, QI Jiawei. 2020: LA-ICP-MS zircon U-Pb dating and genetic types of uranium-bearing granite porphyry in northern Xiangshan orefield, Jiangxi Province. Geological Bulletin of China, 39(1): 62-79.

    江西相山矿田北部产铀花岗斑岩LA-ICP-MS锆石U-Pb定年及成因类型

    LA-ICP-MS zircon U-Pb dating and genetic types of uranium-bearing granite porphyry in northern Xiangshan orefield, Jiangxi Province

    • 摘要: 相山铀矿田是中国迄今为止发现的最大的火山岩型铀矿床,其北部主要铀矿类型为花岗斑岩型铀矿床,铀成矿在时空和成因上与超淺成侵入相的花岗斑岩有关。前人多针对某一具体矿床含矿主岩开展工作,获得的花岗斑岩成岩年龄数据相差较大,影响了对相山花岗斑岩型铀矿的深入研究。选择相山北部横涧、游坊、沙洲、云际等铀矿床的含矿主岩——花岗斑岩系统开展野外地质调查、地球化学特征和LA-ICP-MS锆石U-Pb定年研究,以期厘定相山花岗斑岩型铀矿床含矿主岩的成岩时代和成因类型。花岗斑岩LA-ICP-MS锆石U-Pb定年结果显示,横涧、游坊、沙洲、云际的花岗斑岩206Pb/238U年龄加权平均值分别为135.6±1.3Ma(MSWD=0.45,n=26)、136.2±1.3Ma(MSWD=1.2,n=21)、133.4±11Ma(MSWD=0.67,n=24)及134.3±1.1Ma(MSWD=0.88,n=25),集中在132~137Ma之间,属于早白垩世。研究认为,相山北部花岗斑岩成因类型界于A型花岗岩与S型花岗岩之间的过渡型,为A-S型花岗岩。花岗斑岩岩浆起源于中元古代地壳,地壳物质作为主要成分参与了花岗斑岩的形成,同时有少量地幔物质的加入。花岗斑岩为板内构造界境下伸展体制的产物,可能是由于太平洋板块俯冲后,因板块后撤导致岩浆侵入作用的结果。

       

      Abstract: The Xiangshan uranium orefield is the largest volcanic rock type uranium deposit so far found in China. The main uraniumore type in the north is the granite porphyry type uranium deposit.The uranium mineralization is related to the ultra-hallow intrusion-phase granite porphyry in time and space.Most of the previous work was aimed at the main rocks in a single deposit, and the age date of granite porphyry obtained were quite different, which has affected the in-depth study of Xiangshang granite porphyry uranium orefield. In this paper, the main mineral-granitic porphyry system of the uranium deposits in the northern part of Xiangshan, including Hengian, Youfang, Shazhou and Yunji, was selected to carry out field geological survey, geochemical characteristics study and LA-IXP-MS zircon U-Pb dating, with the purpose of determining the petrogenetic age and genesis type of one-bearing main rocks in Xiangshan granite porphyry uranium deposit.The weighted mean 206Pb/238U ages of granite of Hengjian, Youfang, Shazhou and Yunji are 135.6±1.3Ma (MSWD=0.45, n=26), 136.2±1.3Ma(MSWD=1.2, n=21Ma(MSWD=0.67, n=24) and 134.3±1.1Ma(MSWD=0.88, n=25) respectively, concentrated on the range of 132~137Ma, suggesting the Early Cretaceous period. It is concluded that the original type of granitic porphyry in the north of Xianghan is bounded by the transition type between A-type granite and S-type granite, named A-S granite. Granite porphyry magma originated from the Middle Proterozoic crust. Crustal material, as the main component, was involved in the formation of porphyry, with the addition of a small amount of mantle materal.The granite porphyry was formed by the stretching system under the intraplate tectonic environment.It might have been the effect of magmatic intrusion due to plate retreat after the Pacific plate subduction.

       

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