Research On Structural Characteristics And Uranium Mineralization In Tongliao Area Of ??Songliao Basin

Tongliao area,located in the southwest of Songliao basin,is one of the three uranium resource bases in north China.In recent years,major breakthroughs have been made in uranium geology exploration in this area,which has become a hot spot for sandstone type uranium exploration.The study on the structural characteristics and its relationship with uranium mineralization of the area is not only of great importance to the exploration and deployment of uranium resources but also to the enrichment of uranium mineralization theory in continental basin.Therefore,the regional geological characteristics of the area have been summarized systematically in this article on the basisofthoroughlyanalyzingthepredecessors'achievements,the structure-sedimentary features have also been deduced using the seismic data,and finally some new recognitions are put forward about the characteristics of the Tongliao regional geological tectonic evolution,depositional filling and late tectonic deformation.Tongliao region consists of two primary tectonic units:the Kailu depression and the southwest uplift,which shows the structure of uplift speckled with depression.The tectonic pattern is mainly distributed in the north east?NE?direction with the faults developing.The basement is mainly composed by pre-Cambrian deep metamorphic rock,Paleozoic shallow metamorphic rock and Caledonian granite or diorite,and the cover consist of Mesozoic sedimentary conglomerate,sandstone and mudstone.Basin tectonic evolution can be divided into six stages.The secondary interpretation results of Seismic profile data show:there are 3deep-large cutting shell faults,19 basement faults and 32 superficial faults in the area.The deep fractures are characterized by long and multiple activities with early?K₂q^K₂n?stretching and later?K₂s?thrusting movement.During the Early Cretaceous,the basin basement topographic height difference is big,and Jiamatu uplift is formed.At this period,the basin is generally experienced a retrogradation process,and the provenance systems are of alluvial fan,braided river,meandering river,shallow-water delta and lake,of which the fluvial facies are the main sedimentation.Such sedimentary characteristics are conductive to the uranium mineralization.The uranium mineralization types include interlayer oxidation superposition type,isogenic sedimentary type and submerged oxidation leaching type,which are mainly developed in Yaojia formation of Upper Cretaceous.The main ore controlling factors are of regional structure of cut through basement,certain scale grey sand body and interlayer oxidation zone.Uranium mineralization in gray mudstone is mainly controlled by sedimentary environment,while uranium mineralization in interlayer oxidation zone sandstones is controlled by the front line of interlayer oxidation zone.In the period of Yaojia,the Tongliao area is mainly processing the whole settlement.The grey sand bodies are developing in Lujiapu,Zhanyu and Qianjiadian secondary sag where are of advantageous positions for the uranium mineralization.What's more,the distribution of grey sand is controlled by basin structures.Based on this and previous studies,we propose 2 metallogenic prospective areas named surrounding area of Qianjiadian deposit and Anle.