Study On Deposit Geological Characteristics And Genetic Analysis Of San Cha Chong Tungsten Mine In Bobai City Of Guangxi Province

Sanchachong tungsten ore deposit in Bobai county Guangxi Province is located in Guangxi Luchuan- Bobai Santan polymetallic metallogenic belt which is part of the Bobai- Cen Xi polymetallic metallogenic belt in Guangxi Province,and is grandly belongs to the southwest of Qinhang metallogenic belt. Sanchachong tungsten deposits have a genetic relation with the Yanshanian Sanchachong composite granites. In this paper,we detailedly studied the Sanchachong composite granites and Sanchachong tungsten deposit,and mainly discussed the geochemical properties, magmatic evolution of the Sanchachong composite granites,and the genetic connection with the Sanchachong tungsten deposit. Proposed the trigeminal blunt tungsten ore body is mainly produced in rock mass and the ordovician Middle East chong group(O2d) silicon containing limestone strata within the contact zone of mineralized bodies in rock mass, which belongs to the typical skarn tungsten deposit, controlled by the F5 fault, ore body is layered, vein output.Wall rock alteration are greisenization, silicon card lithification, Angle of lithification, silicide, etc We achieved the following main results and understanding.The zircon U-Pb isotopic dating showed that the Sanchachong composite granites outcropping in the Sanchachong tungsten deposit can be divided into two ages granites. The main granite is medium-grained biotite granite,formed in 105 Ma. The supplementary granite is fine-grained two-mica granite,formed in 103 Ma. We indicate that the Sanchachong composite granites may occur in the magmatism at late early Cretaceous.The Na2 O and K2 O evolutionary trend of the Fine-grained two-mica granite is significantly different from the medium-grained biotite granite and has a higher content of Ca O and Sr. Meanwhile,Fine-grained two-mica granite has a much higher La/Lu ratio. All the evidence suggests that the fine-grained granite may not formed from the fractional crystallization of the medium-grained biotite granite but may occur in the mixing formation of the partial melting caused by the basaltic magma underplating the lower crust and mantle-derived basaltic magmas.Based on the evidence of the field geological investigation,ore deposit geology,petrology and geochemical,we infer that the Sanchachong tungsten deposit has a close contact with the supplementary granite, fine-grained two-mica granite,of the Sanchachong composite granites. Sanchachong tungsten deposit is a skarn tungsten deposit originated from the magmatic hydrothermal activities of the Sanchachong composite granites and controlled by NE trending faults and formations. The mineralization age of Sanchachong tungsten deposit is to be 103 Ma or a bit later,which is late early Cretaceous.