海拉尔盆地贝尔-乌尔逊凹陷古水文地质特征与铀成矿关系OA

In order to find out the internal relationship between the regional paleohydrogeological characteristics and uranium mineralization in the Bell-Wuerxun sag of the Hailar basin,this study use the method of structural analysis,back stripping,analogy method and paleocurrent analysis to clarify the dynamic process of tectonic evolution,paleotopography-geomorphic characteristics and ancient water system development with the data of regional hydrogeology,seismic and core data in the area.By reconstructing the ancient water system,we identified the sedimentary environment and rock geochemical environment of the metallogenic period,and preliminarily summarized the uranium metallogenic conditions in the area.The sedimentary strata since Cretaceous were divided into three hydrogeological cycles.In the first hydrogeological cycle,the weathering and leaching stage was favorable for uranium mineralization and the upper part of Yimin formation was the main prospecting target layer.The formation and evolution process of groundwater in the upper aquifer of Yimin formation was further analyzed.The extrusion water has limited transformation of primary sedimentary water,while the infiltration water has strong transformation of syngenetic sedimentary water.At the same time,the early and late paleocurrent directions of the upper Yimin formation was believed with obvious inheritance.In the Beier sag the direction was from southwest to northeast along the long axis,while in the Wuerxun sag the direction was from east to west.