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为了解准噶尔盆地南缘硫磺沟地区中侏罗统头屯河组砂岩成岩—流体演化与铀成矿响应,进而客观评价其成矿潜力。通过光薄片鉴定、X衍射、扫描电镜分析得出:目的层主要为岩屑细砂岩,依次经历了浅埋藏、深埋藏和表生—热液成岩阶段,遭受较强的机械压实、胶结及溶蚀作用。其黏土矿物以高岭石为主,碳酸盐矿物有细亮晶和泥晶两类,硅质胶结微弱,局部见细晶黄铁矿及其褐铁矿氧化产物。成岩环境可能经历了由酸性到弱碱性再到酸性、由同生期氧化—浅埋期还原—短暂抬升期氧化还原过渡—缓慢沉降期还原增强—快速抬升期氧化的演化过程。砂岩中存在较多油气包裹体;酸解总烃为5.72~449.14μL/kg,以CH4为主;方解石脉δ13CV-PDB为-25‰~-6.7‰,δ18OV-SMOW为11.1‰~18.9‰;结合野外调查认为目的层存在一期中等偏弱的后生油气侵位,从而影响了砂体的Eh及p H值。以上成岩过程及烃类流体活动使得目的层早期形成了小型层间氧化带型铀矿并得以局部保存,晚期形成了一定规模的地表潜水氧化带型铀矿体。
In order to understand the diagenetic-fluid evolution and uranium metallogenic response of the Middle Tunou Group in the Toutunhe Formation in the Sulfur Diver, the southern margin of the Junggar Basin, the objective of the mineralization potential was evaluated. The results of X-ray diffraction and scanning electron microscopy show that the target layer is mainly composed of cuttings and fine sandstone, which have undergone shallow burial, deep burial and epithermal-hydrothermal diagenesis and are subject to strong mechanical compaction, cementation and Dissolution. The clay minerals are mainly kaolinite. The carbonate minerals are fine-grained and clay-type. The siliceous cementation is weak and the fine-grained pyrite and limonite oxidation products are partially seen. Diagenetic environment may have experienced from acidic to weak alkaline and then to acidic, by the same period of oxidation - shallow burial - transient rise of the redox transition - slow sedimentation enhanced reduction - rapid uplift oxidation process. There are many oil-gas inclusions in the sandstone; total acid hydrolysis is 5.72 ~ 449.14μL / kg, mainly CH4; δ13CV-PDB of calcite veins is -25 ‰ ~ -6.7 ‰, δ18OV-SMOW is 11.1 ‰ ~ 18.9 ‰; Combining with the field investigation, it is concluded that there is a moderately weak epicenter emplacement in the target layer, which affects the Eh and p H values of the sand body. The above diagenetic processes and hydrocarbon fluid activities led to the formation of small interlayer oxidized-band uranium deposits in the target formation and their local preservation. In the late stage, a certain amount of surface submersible oxidized-band uranium ore bodies were formed.