• 责任者：Zhao Kuidong (State Key Laboratory of Geological Processes and Mineral Resources ; China University of Geosciences ; Wuhan 430074 ; China) ; Li Jiren
• 刊名：Acta Petrologica Sinica
• 出版年：2013
• 卷期：29(12)
• 关键词：铀矿 ; uranium ores ; 花岗岩 ; granite ; 江西 ; Jiangxi Province
• 页码：p.4349-4361
• 图表：9 illus., 3 tables, 52 refs.
• 分类号：1001
• issnNo：ISSN1000-0569
• isbnNo：CN11-1922/P

     The Xiajiang uranium ore deposit in Jiangxi Province is one of the granite-hosted uranium ore deposits in South China. The uranium orebodies are hosted by the Jintan granitic batholith in the Jiangxi Province. Field geological survey and zircon U-Pb dating indicated that the Jintan batholith is composed of two stage Indosinian granites. The U-bearing two-mica granite was emplaced at 2391Ma, and the porphyritic biotite granite was emplaced at 2262Ma. The two-mica granite has high SiO2 contents （74.09%~74.53%） and low TiO2, CaO and MgO contents. A/CNK values of the granites vary from 1.20 to 1.46, which is consisted with that the granite contains muscovite and garnet. The two-mica granite belongs to typical strongly peraluminous S type granite. However, the porphyritic biotite granite shows different geochemical characteristics. It has relatively higher HFSE and REE contents, lower Rb/Sr ratios and less pronounced negative Eu anomalies. A/CNK values of the porphyritic biotite granite vary from 1.05 to 1.13. Both of the granites have low εNd（t） values （-9.0 to -8.8 for the two-mica granite and -9.8 to -9.4 for the porphyritic biotite granite） with Paleo-proterozoic model ages （1.73~1.75Ga for the two-mica granite and 1.77~1.80Ga for the porphyritic biotite granite）. Geochemical and isotopic characteristics indicate that both the two-mica granite and the porphyritic biotite granite belong to S-type granite. However, the two-mica granite should be derived from anatexis of clay-rich pelitic rocks and the porphyritic biotite granite from partial melting of clay-poor psammitic rocks. We suggested that the two-mica granite formed earlier from dehydrate-melting of crust at syn-collisional compressional environment and the porphyritic biotite granite formed later at the post-collisional extensitional environment. The two-mica granite contains higher U contents, and its mineralogical and geochemical characteristics are similar to those of typical U-bearing granites in South China. Comparative studies indicate that Indosinian U-bearing granites in South China are likely formed from anatexis of pelitic rocks during syn-collisional compressional tectonic regime.