Uranium Mineralization Characteristics And Metallogenic Potential Analysis In Lincang Granite,Yunnan Province

Situated in the south section of the well-known“Sanjiang tectonic metallogenic belt in the southwest of China”,Lincang granite batholith is the important magmatism records of evolution and extinction of the old Lancang River as well as the continental-continental(arc)collisional orogeny occurred between Baoshan and Simao blocks.It is the composite batholith with the largest exposed area in Yunnan Province.Over years,through the efforts of a large number of uranium geologists,significant breakthroughs have been made for uranium prospecting work in the Cenozoic basins of Lincang area,and seven medium and small scale uranium deposits associated and coexisted with coal,germanium and gallium have been confirmed.As the basement of these Cenozoic basins,Lincang granite batholith provides rich uranium sources for sandstone-type uranium mines in basins,which indicates the prospective uranium metallogenic potentiality of Lincang granite batholith.On the basis of collecting and analyzing the existing data in the study area,through field geological survey,some basic maps,such as uranium mine geological map,intrusive magmatic structure map,ground gamma total contour line map,ground gamma spectrometry contour map and so on,have been worked out in the study area,with the scale of 1:25000?1:50000;based on the investigation of the stratum,magmatic activity,structure and alteration of the area,the metallogenic geological background of the study area has been roughly ascertained.Through in-depth study and analysis of geologic,petrologic and petrochemical characters of granite in Lincang area as well as metallogenic characteristics of typical uranium deposits(points),this paper mainly obtains new ideas as follows:1.The study area is located at Jitang-Lancang ancient island arc belt;the main body of“Lincang granite batholith”is controlled by Lancang river major fault zone;the faults and folds tectonic development in the area,and multistage magmatic activities and activities of deep faults provided a large amount of heat and mineral source.2.The geological characteristics of granite type uranium mineralization in the study area are summarized;it is considered that there are tectonic cataclastic altered rock type and quartz vein type uranium deposit,but the former is dominant.3.After two years of geophysical prospecting work,it is believed that at Shuangjiang and Fengqing area,the ground gamma energy spectrum isoline map is obviously controlled by fault structure,and the distribution of high abnormal halos and abnormal halos is mainly controlled by NW and NE trending structures.4.Based on the metallogenic geological characteristics of the uranium metallogenic point and belt which have been ascertained in the studied area,it is considered that uranium mineralization is controlled by faults and dikes,and the fault structure is the main ore controlling factor in this area.The Lancang major fault of nearly North and South trend controls the tectonic framework in the area,and the secondary faults of NW trend and NE trend are the ore controlling structures;most of the ore bodies occur at the intersection of the two faults.5.On the basis of comprehensive analysis,it preliminary delimited Shuangjiang701 prospecting target area of C grade uranium deposit(area:5.4km~2)and Fengqing Huangcaoba prospecting target area of C grade uranium deposit(area:6.23km~2),and it is clear that the main uranium mineralization type in this area is tectonic cataclastic altered rock type.