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    段明, 张博, 汤超, 谢瑜, 滕雪明, 张祺, 徐增连, 魏安军, 蒋职权. 内蒙古额仁淖尔凹陷赛汉组砂(泥)岩地球化学特征及其对铀成矿作用的制约[J]. 中国地质.
    引用本文: 段明, 张博, 汤超, 谢瑜, 滕雪明, 张祺, 徐增连, 魏安军, 蒋职权. 内蒙古额仁淖尔凹陷赛汉组砂(泥)岩地球化学特征及其对铀成矿作用的制约[J]. 中国地质.
    DUAN Ming, ZHANG Bo, TANG Chao, XIE Yu, TENG Xueming, ZHANG Qi, XU Zenglian, WEI Anjun, JIANG Zhiquan. Geochemical characteristics of sand (mud) rocks of Saihan Formation in Erennur sag and their constraints on uranium mineralization[J]. GEOLOGY IN CHINA.
    Citation: DUAN Ming, ZHANG Bo, TANG Chao, XIE Yu, TENG Xueming, ZHANG Qi, XU Zenglian, WEI Anjun, JIANG Zhiquan. Geochemical characteristics of sand (mud) rocks of Saihan Formation in Erennur sag and their constraints on uranium mineralization[J]. GEOLOGY IN CHINA.

    内蒙古额仁淖尔凹陷赛汉组砂(泥)岩地球化学特征及其对铀成矿作用的制约

    Geochemical characteristics of sand (mud) rocks of Saihan Formation in Erennur sag and their constraints on uranium mineralization

    • 摘要:研究的目】查明二连盆地额仁淖尔凹陷赛汉组含铀砂(泥)岩的岩石矿物及地球化学特征,探讨铀成矿作用。【研究方法】包括野外地质编录、偏光显微镜、电子探针能谱分析、主微元素、环境地球化学及铀的价态分析等。【研究结果】表明:①铀矿物以吸附态和独立铀矿物的形式存在,常与炭屑和黄铁矿共(伴)生并发现闪锌矿。②矿石具有高C、S、CO2的特征,泥岩U6+/U4+平均为1.01,砂岩U6+/U4+平均为0.57。③砂(泥)岩的CIA值为50.83-66.34,稀土元素特征与蚀源区花岗岩一致,主微量元素特征均显示存在明显的后期沉积-成岩阶段的水岩作用。【结论】 ①海西期花岗岩是赛汉组砂(泥)岩的主要物源,沉积环境为半干旱-半湿润古气候。②吸附作用和氧化还原作用是研究区铀富集的主要机理,泥岩型铀矿以吸附作用为主,砂岩型铀矿以氧化还原作用为主。③深部流体可能参与了成矿作用。

       

      Abstract: Objective This study aims to ascertain the petrological, mineralogical, and geochemistrial signatures of the sandstone (mudstone) of the uranium bearing target layer in the Erennur Sag, Erlian Basin, and to discuss uranium mineralization.Methods Research methods include field geological cataloging, polarized light microscopy, electron probe spectroscopy analysis, major trace elements, environmental geochemistry, and uranium valence analysis.ResultsThe research results show that:(i) Uranium minerals exist in the form of adsorbed and independent uranium minerals, often co-existing (associated) with carbon chips and pyrite, with occasionally with presence of sphalerite.. (ii) The ore exhibits the characteristics of high organic carbon, S and CO2. The average U6+/U4+ of mudstone is 1.01, and the average U6+/U4+ of sandstone is 0.57. (iii) The CIA value of sandstone (mudstone) is 50.83 to 66.34. The characteristics of rare earth elements are consistent with those of granite in the erosion source area, The characteristics of main and trace elements all show that there is obvious water-rock interaction in the late sedimentation-diagenesis stage.Conclusions The following conclusions can be drawn:(i)The Hercynian granite is the dominant source of the sandstone (mudstone) of the Saihan Formation. The sedimentary environment is a semi-arid-semi-humid paleo-climate. (ii) Adsorption and oxidation-reduction are the main mechanisms of uranium enrichment in the study area. Mudstone-type uranium enrichment is mainly in the form of adsorption, while sandstone-type uranium enrichment is mainly in the form of oxidation-reduction. (iii)The deep fluid may have participated in the mineralization.

       

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