Uranium Metallogenic Conditions And Prospecting Prediction Of Shijiazi-xinchengzi In Chifeng City

Wushijiazii-Xinchengzi area is located in the middle-south section of Daxing'anling Mountains and is also one of the important uranium-polymetallic ore deposit concentration areas in China.On the basis of the geological background of the study area,taking the Wushijiazi,Xinchengzi,Shiertu secondary volcanic basins and Baiyinshanalinchang caldera as the objects,this paper expounds the metallogenic geological characteristics from the aspects of basement,caprock,structure,intrusive rocks,hydrothermal alteration and uranium mineralization characteristics.According to systematical analysis of geological conditions of uranium mineralization comparing them with the known uranium deposit,the basins in this area have the characteristics of"multi-structural planes,main fault-cut crust,dyke filling,altered superimposition and mineralization development".On this basis,prospecting prospects are predicted in order to provide new ideas and data support for uranium prospecting work in the next step.?1?The study area has favorable geotectonic background;the uranium content of basement,caprock and intrusive rock is?4.5¹1.5?×10^-6,and the uranium source is abundant.It is found that the contact zones of volcanic rock and intrusive rock in the study area have obvious control function over uranium mineralization,and most of the uranium mineralization found occurs in contact zones of Manketou Obo Formation acidic volcanic rocks and acidic intrusive rocks.?2?The study area is located in the superimposition part of main ridge of NE-trending Daxing'an Mountains and EW-trending Xilamulunhe deep fault,and Huanggangliang-Wulanhaote deep fault run through the area.The faults controls the distribution of volcanic basins,intrusive rocks,secondary structures and uranium-polymetallic mineralization.The intersection of secondary faults is the favorable location for uranium mineralization.Overall,uranium-polymetallic mineralization is more enriched near the basement uplift zone.?3?Hydrothermal alteration is widely developed in the region,and mainly is medium-low temperature alteratio.There are mainly silicification,hematitization,feldspathization,chloritization,fluorination and pyritization,among which hematitization and fluorination are the main wall rock alteration near the mine.?4?It is considered that uranium-rich volcanic strata and intrusions,multi-stage faulting activities and multi-type hydrothermal alteration are the main controlling factors for uranium mineralization in this area,while the depression area near the basement uplift zone,the interlaced parts of multiple faults in NE-trending faults zone,the staggered position of faults and volcanic institutions,the inside and outside contact zone of intrusive rocks are the favorable ore-hosting sites in this area.?5?The origin of uranium mineralization in this area is mainly volcanic hydrothermal solution.Through the uranium metallogenic conditions,8 criteria for prospecting and 6prospecting indicators are summarized.According to the structural environment of mineralization anomaly,the volcanic type uranium mineralization in this area is divided into two subtypes,these are altered fissure zone type and subvolcanic rock type,and 8 prospecting target area is preliminarily delineated,1 uranium metallogenic prospect area is predicted.