华南板块西缘个旧白沙冲花岗岩地球化学特征、构造背景及铀成矿潜力探讨OACHSSCD

Multiple Yanshanian granite are exposed in the Gejiu region,located along the western margin of the South China Block.This area represents a significant polymetallic ore district characterized by tin,REEs,and other metals.The mineralization exhibits a close genetic association with the granite.Furthermore,these magmatite display elevated uranium enrichment.Based on field geological investigations,this study conducted petrological,geochemical,and zircon U-Pb geochronological analyses of the Baishachong pluton.And comparative analysis was performed with both well-known uranium-bearing granites in South China and representative uranium-bearing granites from other regions foreign.Field investigations reveal that the Baishachong pluton is predominantly composed of medium-to-fine-grained biotite granite.zircon U-Pb weighted age dating of the Baishachong granite yields an age of 89.4±2.4 Ma.This age is comparable to those of diverse magmatic pluton within the region,indicating that they are all products of magmatic activity during the Late Yanshanian period.Geochemical analyses show that the granite is highly acidic,alkaline,characterized by the enrichment of LREEs,10 000×Ga/Al>2.6 and zircon saturation temperatures ranging from 772℃to 855℃reflect high-temperature conditions,exhibiting geochemical characteristics of highly fractionated A-type granites.The Nb/Ta and Zr/Hf ratios of the Baishachong granite are consistent with continental crustal compositions and with Nd isotopic compositions suggest that the Baishachong are mainly derived in the crustal.Through the comprehensive study of regional geology,geochronology,and geochemistry,it is inferred that the Baishachong granite pluton is a product an extensional tectonic setting which related to Neo-Tethyan subductio.Comparative analysis of the geological and geochemical characteristics between the Baishachong grantie and well-known uranium-bearing grantie domestically reveals certain similarities.Combined with the geological features and the abundant surface uranium anomalies present of the Baishachong pluton,this strongly suggests that the Baishachong granite possesses favorable potential for uranium mineralization.This study not only enhances our understanding of the formation mechanism of the Baishachong pluton but also provides significant theoretical guidance for uranium exploration in the region and for comprehending the tectonic evolution of the western margin of the South China Block and its relationship with uranium mineralization.Furthermore,it is also of great significance to explore new areas of granite-type uranium deposits in the South China region.