鄂尔多斯盆地北东部红庆梁地区铀成矿规律及其找矿意义

Uranium metallogenic characteristics and prospecting significance of Hongqingliang area in northeastern Ordos basin

鄂尔多斯盆地北东部发育一条主体走向呈NNW向的铀成矿带,为进一步评价成矿带中段呼斯梁东–柴登壕西一带的铀成矿潜力,基于煤田资料的铀矿二次开发技术,选取该地段铀矿研究程度较低的红庆梁地区为研究对象,开展地层结构、砂体厚度、顶底板展布及沉积构造演化等成矿地质条件分析,重点研究区内铀矿化规律和主控因素,预测成矿远景。综合分析认为,红庆梁地区铀成矿目的层直罗组下段下亚段泥–砂–泥结构发育,砂体厚度大且呈泛连通状态,目的层沉积期后曾隆升剥蚀出露地表接受含氧含铀水的渗入,铀成矿条件优越,同时砂体非均质性控矿强烈,古层间氧化成矿特征明显,氧化还原障和砂体的非均质性共同控制红庆梁地区铀矿(化)的空间位置。建议下一步工作向红庆梁地区南东和南西两侧有针对性外推。

A NNW trending uranium metallogenic belt was found in the northeastern Ordos basin in last 20 years.In order to evaluate further the mineralizing potential of the middle part of this uranium minerogenetic belt,we choose a typical less developed area:Hongqingliang area as a research object to analyze its ore-forming conditions on the basis of the secondary development of coalfield data.These ore-forming conditions are composed of characteristics of stratigraphic structure,sand thickness distribution,spatial morphology of roof and floor,the sedimentary-tectonic evolution of Zhiluo Formation and so on.After comprehensive analysis of uranium mineralization law and ore controlling factors,we conclude that in Hongqingliang area mud-sand-mud structure was developed in the uranium metallogenic target layer(subsection of the Lower Section of Zhiluo Formation),the sand bodies are thick and show panconnected state,after the period of deposition,the target layer was lifted,denuded and exposed on the ground surface,accepted infiltrated uranium-bearing water,the uranium metallogenic conditions were advantageous,in the same time,the sand bodies had intense nonhomogeneous control on uranium deposit,the metallogenic characteristics of paleo-interlayer oxidation are evident.The spatial positioning of uranium mineralization in Hongqingliang area is controlled conjointly by the oxidizing reducing barrier and the heterogeneity of the sand bodies.The future work is to extrapolate exploration to the west and east sides of Hongqingliang area.