Sedimentary Evolution and Uranium Prospecting Direction of Qingshankou Formation in Southern Songliao Basin
As the prospecting space in the Qianjiadian mine and the peripheral uranium ore belt is getting smaller and smaller,the new area and new horizon become the the urgent need for uranium exploration in the southern Songliao Basin.And the Qingshankou Formation was systematically re-recognized.Based on the core,logging and production dynamic data of a large number of boreholes,the top and bottom interfaces of the Qingshankou Formation in the region were first redefined.Based on the achievement of accurate stratification,the stratigraphic filling,provenance system,the sedimentary facies and sand body distribution characteristics were systematically studied,so as to further explore the ore-bearing characteristics of the Qingshankou Formation,the relationship between sedimentary evolution and uranium mineralization.The results showed that:(1)Affected by the structure of the depression basin and the central Jiamatu uplift,the thickness of the Qingshankou Formation in the southern part of the study area varies greatly,showing a concave-uplift pattern,which is characterized by eastern uplift and denudation-central subsidence-western uplift loss.(2)There were three provenance systems.The main provenance was the Kangping-Faku area on the southern margin of the basin.From south to north,it showed an alluvial fan-river-delta-lake sedimentary system,and the sedimentary pattern of South Hebei Island was bounded by the central paleo-uplift.(3)The sand bodies were mainly developed in the Kailu depression in the southwest,and the channel was of the characteristics of converging to the saddle of the central paleo-uplift.The area where the water flow converged was the development site of the favorable gray ore-forming sand body.Based on this,the metallogenic genesis of the water-blocking and sand-accumulating in the paleo-uplift was proposed.Finally,according to the research results,two suggestions were put forward for the prospecting direction of uranium deposits in the study area:(1)The newly added Qingshankou Formation is the primary target layer in the study area,and the prediction of ore-bearing sand bodies follows the law of continuous upward movement from south to north.(2)The paleo-uplift saddle-shaped valley pattern catchment,channel sand body superposition site and end sedimentary phase change site,paleo-uplift and depression connection site were believed the prospecting direction of sandstone-type uranium deposits.This study improved the basic geological research level in this area,and provided reference for expanding the prospecting space.
ancient upliftQingshankou Formationsedimentary fillingsandstone-type uranium depositssouthern Songliao Basin
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