The Metallogenesis Of The Xinqi Tungsten-tin-polymetallic Deposit In Yunnan Province

The Xinqi tungsten-tin-polymetallic deposit is located in about 5km northwest of Xinqi,Tengchong country,in the Gaoligong-Tengchong fold belt,the north west part of the southeast Asia tin ore belt,it has adequate ore source and complete metallogenic mechanism,it's typically a magmatic hydrothermal deposit of Sanjiang metallogenic belt.The host rock are Upper Carboniferous Menghong Croup shallow metamorphosed slate,sandy slate;the mineral bearing rock is Xinqi granite mass,nearly NS F2 fault,which is consistent with the regional tectonic lineament,control the main distribution of ore bodies,the secondary faults are host structure.Ores are divided into greisen type and qyartz vein type,the former mainly enriches tin and the latter mainly enriches tungsten;mineralized alteration generally developed in the mining area,mainly is muscovitization,silicification,greisenization etc.The characteristics of the ore-forming fluid are low medium tempreture and low salinity.According to the thrust relation and metallogenic regularities,the samples are divided into main metallogenic period and non-ore quartz vein period,and the main metallogenic stage can be divided into tin-greisen stage and wolframite-cassiterite-quartz vein stage,inclusion types are relatively single,most NaC1-H20 fluid inclusions(W),daughter mineral bearing inclusions(S)are rare.The homogenization temperature is between 360°and 100°,homogenization temperature falls and salinity does not change obvious after tin-greisen stage.Xinqi granite mass is alkalinity-sub-alkalinity and peraluminous,is the product of thickend crust sedimentary source area decompression melting,is similar to the mineral bearing rocks of the other lithophile series tungsten-tin deposits in the area.Intrusion age has two phases,60Ma and 120Ma,60Ma closely linked to 1 tungsten-tin ore occurrence,120Ma closely linked to 2 tungsten ore occurrence.The metallogenic materials of Xinqi tungsten-tin-polymetallic deposit mainly come from late magmatic evolution hydrotherm,the formation just offer holding ore space,is a typical magmatic-hydrothermalore deposits.