二连盆地那仁地区铀成矿地质条件分析及找矿预测

经过近年来的区域评价工作,在内蒙古二连盆地那仁地区赛汉组上段发现了铀矿化信息,但由于工作程度较低,铀成矿条件分析及远景预测明显不足。通过对钻孔、地震等资料的综合整理,结合系统取样、分析测试结果,对那仁地区铀源、构造、地层、沉积相、氧化-还原及古气候条件进行了全面分析。研究认为该区铀源充足,在温暖半湿润—干热气候转变期,蚀源区大量的铀被活化、迁移;晚白垩世—新生代的构造活动提供了适宜氧化带发育的斜坡带及深部还原流体上逸通道;赛汉组上段一亚段辫状河三角洲砂体规模大,具备稳定的泥-砂-泥结构和有利的氧化-还原条件,是铀矿形成的理想空间。在铀成矿条件最佳部位预测Ⅰ级远景区1片,有望落实为新的铀矿床。

Analysis on Uranium Metallogenic Geological Conditions and Prospecting Prospects in Naren Area,Erlian Basin

Although uranium mineralization information has been found in the upper member of Saihan Formation in Naren area through regional evaluation in recent years, the analysis of uranium mineralization conditions and prospective prediction are obviously inadequate due to the low level of work. In this paper, the uranium source, structure, stratum, sedimentary facies, oxidation-reduction and paleoclimate conditions in Naren area are comprehensively analyzed based on the comprehensive arrangement of borehole and seismic data, combined with systematic sampling, analysis and testing results. The authors believe that uranium source is sufficient in this area, and a large amount of uranium was activated and migrated in the erosion source area during the warm sub-humid to dry hot climate transition period. The Late Cretaceous-Cenozoic tectonic activity provided the slope zone suitable for the development of oxidation zone and the upward passage of deep reducing fluid. The first sub-member of the upper Saihan Formation has braided river delta sandbodies with large scale, stable mud-sand-mud structure and favorable oxidation-reduction conditions, which are ideal space for uranium ore formation. In the best position of uranium mineralization condition, there is one prospective area of grade Ⅰ, which is expected to be implemented as a new uranium deposit.