The Ore-controlling Structure And The Ore-forming Characteristics Of Shuixie Cu-co Deposit, Yongping, Yunnan

Shuixie Cu-Co deposit,Yongping,Yunnan is a mainly Cu,Co associatedpolymetallic deposit,which is located in the western margin of the south of Lanpingbasin,in the east of Lancang River fault zone,is a SME deposit of Lancang copper(polymetallic) metallogenic belt,is a hydrothermal copper deposit.According to the earlier field construction research and combining interrelatedinformations define that the structural framework of the area is overthrust structurewhich formed in Hercynian—early Himalayan:in the west starting by Chang—Mengmélange zone, to east in proper order is central nappe that are Chongshan rock groupand Triassic granitoids.In the band metamorphism is very strong;Lancang River faultszone are leading construction of the area;Piedmont nappe are Wuliangshan rockgroup,in the band metamorphism is weak,and from west to east metamorphism ismore weaker;Juebashan—azhagu fault is thrusting fault and its bottom maybe linkedLancang River fault;Foreland thrust belt,developing a series of thrusts and formingimbricated structures,including Laojunshan fault、 alang fault and gouhe—shilifault,form fault block of varying scale.These faults are often caused by the formationof the derived folds;Slip deformation zone of the leading edge of the basin:tupitaiwide syncline and heihui river closed anticline composed barrier-type folds,but thefaulting is weak,the main fracture have chahe fault and laozhujie fault.Based on geological survey in the open field,comprehensive laboratory analysisand the previous studies results：Shuixie Cu-Co deposit is becoming in Himalayanperiod,outputting in the form of vein,lenticular and stratoid.The ore is mainlytennantite. Isotopic studies indicate that ore-forming fluid is from the deep crust，andit is from the mixture of magmatic water with atmospheric water and stratum water.Inclusion composition is mainly H2O and CO2, mineralization temperature is about141°—253℃. It is the type of mineralized in medium-low temperature.The characteristics of the Ore-controlling structure of Shuixie mine：faultsstructures are very upgrowth,NW、NNW-trending thrusting faults are the mainconstruction line of the mine.The trending faults’scale is varying,fracture face mostlytrend to SW or W,a few to NE,and they are all steep.Fault zones are obvious strongdense cleavage zones which caused stratum steeply dipping or upright,and formed strong broken zones,and with mineralization and hydrothermal metamorphism insome place.These reflected the mine had been strongly squeezed.Folds which formedin this period are caused by the faults,especially F4and F5’control function.LaterNE、NEE and EW-trending faults had formed in the mine,these breaking’s scale isrelatively small.They often move NW、NNW-trending faults to the left,the left-shiftdistance is about100-200m.The faults’face is serrated that indicate tensional nature.Tensional distance is about2-3m,tension zones are broken zones.This period the minebe given shift-tensile force.The characteristics of the structure ore-controlling of Shuixie Cu-Co deposit：Lancang River fault zone is ore-passing structures；NW、NNW-trending faults(F4、F5、F9、F10) and NE、NEE、EW-trending strike-slip faults are ore-controllingstructures；NW、NNW-trending structures and NE、NEE、EW-trending structures areimportant ore-storage structures.Stratums of the T3m and the T3sh are importantore-storage stratums.Geochemical results of the alin ore block show elements aberrant zones(areas)correspond well with NW、NNW-trending fault’s broken zones and interlaminarfracture zones,it indicates that NW、NNW-trending faults are important on ore-controlling aspect.Combined with regional tectonic evolution,the model of the ore-controllingstructure of the area is:Lancang River faults zone of the late Hercynian is a deepfault,it linked the deep hot brine and magmatic hydrothermal in deep crust. Orogenyand strike-slip movement in Yanshanian-Himalayan period formed mainlyore-controlling structures and ore-storage structures.In the driving force,the deephydrothermal moved up along the ore-passing structures(Lancang River fault),andfilled in the ore-storage structures along the ore-controlling structures,such as faultfracture zone,and formed corresponding orebodies.Using the metallogenic characteristics and prospecting model of shuixie Cu-Codeposit on prospecting prediction in goujie,and1:50000geochemical aberrant zonesconsistent with fault’s zones,so we delineate three prospectingtargets:lidongshan-xiaoyanzigen,sanpianshi-wujiazhai,xianshuidong-longhua-dazhai.