Guangxi Calcite Tin Polymetallic Deposit Calcite Earth Chemical Characteristics Study

The Tongkeng tin polymetallic deposit is the most representative super-large deposit in the Dachang tin polymetallic field in Guangxi.It consists of an upper tin polymetallic ore body and a deep zinc-copper ore body.Based on the previous work,this paper systematically carried out a comparative study of rare earth and C and O isotopes of calcite in different types and different types of ore bodies.Work shows:(1)The rare earth coordination pattern of the upper tin polymetallic ore body and the deep zinc-copper ore body is obviously different.The rare earth distribution pattern of calcite in the tin polymetallic ore body has a large change,and the loss-positive anomaly(?Eu=0.4-3.5)The rare earth partitioning mode is right-dip-flat type;the rare earth partitioning mode of calcite in zinc-copper ore body is basically the same,and there are significant positive anomalies(?Eu=1.5-4.6),which are generally right-inclined.It indicates tin polymetallic ore-forming fluid The source is more complex than the deep zinc-copper ore.(2)The rare earth Y/Ho ratio of calcite shows that the rare earth of calcite ore in the Tongkeng deposit(4.6~34.2)is significantly lower than the corresponding ratio of the layered ore body(34.4~41.5).The Y/Ho ratio of the rare earth calcite of the veined ore body is close to that of the Long Box Cover Rock Mass(26.6),but lower than the modern seafloor hydrothermal value(25-50);the Y/Ho ratio of the layered ore body is significantly higher than that of the Dragon Box.Cover the rock mass,and close to the modern seabed hydrothermal fluid.It indicates that the hydrothermal calcite in the veined ore body is mainly magma,while the layered ore body has the participation of seabed hydrothermal fluid,that is,the Devonian submarine jet provides some mineralization for layered mineralization.(3)The calcite?13C(‰)PDB of different types and different ore bodies in Tongkeng mining area are negative(-0.4~-8.9),which is between magmatic fluids(-18.0~27.0).Between the surrounding rock and the surrounding rock(0.56);?18O‰(Smow)(10.30-17.08)is higher than the rock mass(10.95)and lower than the stratum.(22.44).It indicates that the ore-forming fluid in the area should be a mixture of stratum and magma fluid.(4)The C and O isotope values of the layered mineralized samples in the Tongkeng mining area show a positive correlation,the hydrothermal degassing,the water-rock reaction between the fluid and the surrounding rock,especially the mixing of the fluids The main mechanism of calcite precipitation.(5)There is the participation of mantle-derived materials in the layeredmineralization,but no information on the participation of mantle-derived materials is found in the rock mass of the Long Box Cover.Therefore,the mantle source in the mineralization may come from the Devonian submarine spray.The genesis of the ore deposit is not only the cause of magmatic hydrothermal fluid,but also the multi-source and multi-genesis mineralization of the late Yanshanian magmatic:fluid.