The Geochemical Characteristics And Uranium Metallogenic Conditions Of Lincang Indosinian-Yanshan Granites In Yunnan

Lincang granite belt is located in the south of Sanjiang metallogenic belt.The previous research focuses in the copper,zinc,gold and other minerals.There is no detailed survey and evaluation of the mineralization potential of granite-type uranium deposits.There is still a lack of comprehensive and systematic uranium geological work and comprehensive research.The Lincang granite belt shows high uranium geochemical anomalies in the area,The Fengqing 901 mineralization point and the Shuangjiang 701 mineralization point have been found in Lincang rock mass,which shows a good prospect of uranium metallogenesis.Predecessors have carried out certain exposure work on the two ore points,and later due to the focus of work became concentrated in the exploration of the basin,ignoring the prospect of mineralization as a uranium source,resulting in a relatively low level of research on the two mineralized sites and an unclear uranium metallogenic potential.In this paper,from the perspective of uranium mineralization,on the basis of collecting previous data,through field geological surveys and later data compilation and comprehensive research,Lincang Indosinian-Yanshan granites for the petrology,chronology,geochemistry research,on the geological and geochemical characteristics of typical uranium points are analyzed.The parameters obtained were related to the parameters of typical uranium-producing granites in South China.To compare the uranium metallogenic conditions.Get the following understanding:(1)The study of petrology shows that there is a wide distribution of granite in Lincang Indosinian-Yanshan granites,and the granite lithology is mainly black mica,two long granite and granite diorite.The combination of minerals is single,and the grain sizes are different.Some of the sections are affected by the late tectonics.Become a directional structure.(2)Geochemical studies have shown that Lincang Indosinian-Yanshan granites generally have features of silicon-rich,alkali-rich,and aluminum-supersaturated,with high potassium,calcium,and alkaline series,and major elements,trace elements,and rare earth elements.The elemental characteristics are similar to those of uranium-producing granites in South China,and have the general characteristics of uranium-producing granites in South China.(3)The geochemical analysis reveals that the genetic type of Lincang Indosinian-Yanshan granites is dominated by s-type,while yanshanian granite is mixed with a small amount of type I granite.The source of the magma is the shell source,which belongs to the post-collision granite.(4)According to the research of chronology,the granite of lincang granite is characterized by multiple ages and multiple magmatic activities.The most widely distributed in the Lincang granite belt is the Indosinian granite.The Yanshanian granite is mostly a small rock body or a rock strain invades the monzogranite body.The granite age composition in the local section(Shuangjiang North East)is dispersive and represents a complex source of magma material.(5)The study of typical uranium deposits shows that the uranium mineralization at the Fengqing 901 uranium ore site is most closely related to hematite mineralization and sodiumization,and negatively related to silicification;the uranium enrichment at this deposit is accompanied by the loss of thorium,with the degree of chemical transformation is strengthened,total rare earth is reduced,and light and heavy rare earths are weakened.The uranium mineralization process in the fracture zone of Shuangjiang 701 uranium deposit is accompanied by the processes of alkali elimination,aluminum reduction,and hematite enhancement;uranium has obvious enrichment in the fracture zone,and the light-heavy-earth heterogeneity in the fracture zone is weaker than normal granite?(6)Compared with the characteristics of typical uranium-producing granites in South China,it is shown that the Lincang granite belt has better uranium source conditions,tectonic conditions,and geochemical conditions.Indosinian granite uranium metallogenic conditions and potential are better than Yanshanian granites.