Discussion On The Relationship Between Alkali Metasomatism And Uranium Mineralization In The Chaganhada Area Of The Weijing Pluton In Inner Mongolia

The study area is located in the north-central part of Inner Mongolia Autonomous Region,the western part of the Bayinbaolige uplift,and the central part of the Central Asian orogenic belt.It consists mainly of the Lower Permian intermediate-acid volcanic rocks and the Yanshanian-based granitoids.This paper systematically studies the characteristics of granite geology,rock geochemistry,wall rock alteration,uranium mineralization and uranium metallogenic conditions in this area.Moreover,a preliminary discussion has made on the metallogenic model,and the prospecting potential of the uranium mineralization in the Chaganhada area has analyzed.Through systematic petrographic analysis,main trace,rare earth element analysis and electron probe analysis of rock samples in Chaganhada area,it shows that the Chaganhada area of Weijing Rock mass is a typical alkali-intercalated uranium mineralization.The alteration in the borehole is dominated by alkaline corrosion,the potassium feldspar content in the alkali metasomatic ore is significantly reduced,the sodium long petrochemical is obvious,and with the chlorite and hematite mineralization,sodium metasomal phenomenon occurs in the alkali metasomatic ore.According to the analysis of electron probes,the uranium in the study area is mainly composed of independent uranium minerals,namely uranium vermiculite and siliceous uranium ore.The alkaline metasomatic uranium mineralization in the Chaganhada area of Weijing has the enrichment pattern of “upper alkali acid”,which is consistent with the most basic mineralization process and metallogenic mechanism of hydrothermal action.Compared with the typical alkaline metasomatic uranium deposit in China,this area has a great similarity with the Gansu Jiling uranium deposit,which means that this area has good uranium metallogenic geological conditions and good prospecting prospects.Combined with the analysis of uranium metallogenic conditions,the uranium mineralization prospecting area has predicted,and the area has been divided into 4 prospects.Among them,there are 2 prospective areas in Class II,namely Chagan hada pluton and Bayanaobao pluton;2 prospective areas in Class III,namely the uranium metallogenic prospecting area of the Aobaotu-Weijing and the uranium mineralization prospecting area of Xilimiao.