Discussion On Metallogenic Characteristics And Genesis Of Weilasituo Sn Polymetal Deposit In Inner Mongolia

The Weilasituo Sn deposit is a located in the western slop of southern metallogenic belts in Da Hinggan Mountains of Inner Mongolia.It belongs to magmatic_hydrothermal complex deposits.In this paper,Combined with regional geological background and the geochemical analysis of quartz porphyry Fluid inclusions,we can sum up the following understanding(1)The quartz porphyry of Weilasituo Sn deposit strongly depleted in Ca,Mn,P,and enrichment of Si,Al.,Ore-forming elementsW,Pb are also rich.Conclusion Thinking over the trace element.In high field strength elements(HFSE)such as Nb,Zr are high and Ti is low.Large Ion Lithophile Elements(LILE)strongly depleted in Ba,Sr and enrichment of Rb,K.(2)Weilasituo quartz porphyry are characterized by high K calc-alklline magama or calc-alklline magama,strongly peraluminous.The high differentiation index shows that the rock mass has undergone a high degree of differential evolution.(3)In the rare earth element,fractionation of heavy rare earth and Light rare earth shows weak.LREE relatively enrich.In REE,the chondrite-normalized REE partition incline to the right deviation,REE distribution patterns show a "V",a strong negative Eu anomalies.(4)Analyzing test results of the quartz fluid inclusions associated with the mine reveals that the main type of fluid inclusions in the Weilasituo Sn deposit is gas-liquid two-phase inclusion.The study of fluid inclusions shows that the ore-forming fluid is middle in temperature,low salinity,low-to-middle density.(5)According to research and previous achievements about the Weilasituo Sn deposit,the tectonic environment of the rock mass is extensional environment in the plate and lithospheric thinning.It is greatly affected by Yanshan stage and subvolcanic activities.The magma evolved into ore bearing hydrothermal fluid continuously,it could be Magmatic-hydrothermal composite deposit.