Uranium Metallogenic Regularity And Prospect Prediction Of Upper Cretaceous Yaojia Formation In Southern Songliao Basin

Southwest songliao basin in cretaceous yaojia newly discovered several in-situ sandstone-type uranium deposits,has proven the industrial oxidation zone in the area of uranium ore body ore-controlling role,local area closely related to uranium mineralization and low temperature hydrothermal process.The study and the knowledge of the mechanism of the mineral deposits in the typical uranium deposits in the area,can be further helpful to summarize the uranium mineralization pattern in the area,the important foundation of the regional vision prediction.By field drilling core,logging and sampling,this paper summarized all kinds of geological data,the structural framework of ore deposit,lithology,lithofacies,magmatic activity,groundwater flow,oxidation and other control factors were analyzed.In combination with microscopic thin section identification,electron microprobe analysis,isotope analysis test sample data,such as analysis of epigenetic alteration type,type uranium ore species,composition and occurrence state,stable isotope characteristics,etc.The metallogenic characteristics of ore deposit are summarized,and the metallogenic model of sandstone type uranium deposit is established.The basic laws of uranium mineralization in yaojia formation are as follows:The output of uranium deposit is closely related to the structure,and it is obviously controlled by NE fracture.NE fracture to construct the structure of the braided river sand body of yaojia formation and the basic form of constructing the skylight,to communicate the deep reducing fluid.At the same time,the activity of basic magma in the region is controlled,and the thermal fluid is formed,which provides favorable heat events for the activation and migration of uranium.Kailu basin,southwest depression content source by the southern margin of the basin,there is Naiman-Dongming,Ganqika-Chaolutu figure in recharge area,two main source in the Dongmin-Donglai-Yuliangpu-Tongliao – Baolongshan line development is about 150 km long,about 50 km wide of braided river facies sand body,good permeability,stratification and connectivity.At the same time,the yaojia formation was overlying the mudstone of the nenjiang formation,and then the mudstone of the qingshankou group or the fuxin group,with stable mud-sand-mud structure.The interlayer oxidation zone in yaojia formation extends from the basin edge to the basin,and develops in the Longwantong-Shuangbaozi-baolongshan area.The oxidation-reduction transition zone is distributed in Dongming-Donglai and Yihuta-qianjiadian area.Multiple uranium deposits have been found in the oxidization and reduction transition zone of Tongliao-Baolongshan in the depression of qianjiadian Basin.The yaojia formation has a good complement-diameter-drainage system,The groundwater as a whole flows from SW to NE,Uranium containing oxygen is supplied from the edge of the basin,From the structural denudation skylight-the discharge from the new river,F2 and F3 fracture also play a role in local excretion.In addition,the yaojia formation uplifted in the eastern co-generation granite uplift,To receive the fourth-series diving supplies.Therefore,the eastern co-generation granite ancient uplift zone is the secondary recharge area of yaojia formation.Its runoff direction is SE to NW,In the structure of the denudation skylight-new drainage area.In summary,The enrichment of uranium in the region is controlled by fracture,braided river and interlayer oxidation zone.In the local area also controlled by the thermal fluid and magmatic activities produced by the structure,The formation of the deposit is characterized by the superposition of the mineralization and the mineralization of the deep heat fluids.The formation of ore deposits is the product of long-term coexistence of endogenetic and exogenous mineralization.