| 二连盆地西部隆起区卫境岩体铀丢失与盆内铀矿成矿关系探讨 |
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| 关键词:uranium source uranium lose Pb isotope Weijing granite Erlian Basin |
| 基金项目:国家自然科学基金项目(编号: U2067202; 41772068; 41862010; 42172098);国家重点基础研究发展计划973计划“中国北方砂岩型铀矿流体成矿过程研究”(编号: 2015CB453002) |
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| Study on Uranium Loss of Weijing Granite and Sandstone-type Uranium Mineralization in Erlian Basin |
| A series of sandstone/mud-type uranium deposits in Erlian Basin over the last 20 years have been determined to be proven deposits, making Erlian Basin an important uraniferous site in China. Weijing granite, which is located in the Bayinbaolige uplifted zone in the northwest of the Erlian Basin, is a multi-staged granite batholith (from Hercynian to Yanshanian), with a large distribution area (>1000 km2), and is surrounded by several uranium deposits. In order to study the relationship between Weijing granite and uranium mineralization, field geological investigation was conducted, in which a series of samples of Weijing granite and sandstone of the Saihan Formation were collected. Through microscopy, the Weijing samples were identified to be medium to coarse-grained biotitic, porphyritic-like granite. Petrological analysis revealed that the sandstone of Saihan Formation consisted mainly of quartz, feldspar (plagioclase and potash feldspar), and lithic fragments sourced from granites. The analytical results of the rare earth elements indicated that the material source of ore-hosting sandstone is Weijing granite. The Pb isotopic analysis demonstrated that the primitive uranium content (U0) of Weijing granite is high, averaging 15.17×10–6. However, the average uranium loss amounts to –45.47%. Similar to granite, the oxidized sandstone of Saihan Fm has obviously lost uranium, with an average of 41.42%. However, the reduced sandstone of Saihan Fm is rich in uranium at an average of 66.8%. Hence, our findings indicated that Weijing granite provides sediment sources for sandstones as well as uranium sources for uranium mineralization in Erlian basin sandstone. From apatite track analysis, we found that the Weijing granite and its adjacent area were rapidly uplifted during Late Cretaceous to Eocene (76.7–53.8 Ma). This tectonic activity was contemporaneous with the uranium mineralization in sandstone and mudstone, indicating that the uplift triggered the uranium mineralization. |
| NIE Feng-jun,XIA Fei,YAN Zhao-bin,JIANG Mei-zhu,HE Jian-feng,YANG Dong-guang,FENG Zhi-bing,ZHANG Cheng-yong,ZHANG Xin,LÜ Yong-hua,HU Jian.2022.Study on Uranium Loss of Weijing Granite and Sandstone-type Uranium Mineralization in Erlian Basin[J].Acta Geoscientica Sinica,43(5):616-632. |
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