The Ore-controlling Structure And The Ore-forming Characteristics Of The Bat Cave Antimony Deposit, Weishan, Yunnan

The Bat Cave antimony Deposit, Wei shan, Yunnan is a mainly antimony associated polymetallic deposit,which is located in the eastern margin of the south of Lanping basin,in the east of Lancang River fault zone,is a SME deposit of Lancang copper(polymetallic) metallogenic belt,is a hydrothermal copper deposit.Based on geological survey in the open field,comprehensive laboratory analysis and the previous studies results : The Bat Cave antimony deposit is becoming in Himalayan period,outputting in the form of vein,lenticular and stratoid.The ore is mainly tennantite. Isotopic studies indicate that ore-forming fluid is from the deep crust,and it is from the mixture of magmatic water with atmospheric water and stratum water. Inclusion composition is mainly H2 O and CO2, mineralization temperature is about 130°—150℃.It is the type of mineralized in medium-low temperature.Acording to the geochemical research results of bat cave ore block,we can know the element anomaly zone(area)have a good corresponding relation between layers with NW, NNW fault fracture zone and fissure zone,showing hat the NW, NNW to fracture structure plays an important role in controllingAccording to the earlier field construction research and combining interrelated informations define that the structural framework of the area is overthrust structure which formed in Hercynian—early Himalayan:in the west starting by Chang—Meng mélange zone, to east in proper order is central nappe that are Chongshan rock group and Triassic granitoids.In the band metamorphism is very strong;Lancang River faults zone are leading construction of the area;Piedmont nappe are Wuliangshan rock group,in the band metamorphism is weak,and from west to east metamorphism is more weaker;Juebashan—azhagu fault is thrusting fault and its bottom maybe linked Lancang River fault;Foreland thrust belt,developing a seriesof thrusts and forming imbricated structures,including Laojunshan fault 、 alang fault and gouhe—shili fault,form fault block of varying scale.These faults are often caused by the formation of the derived folds;Slip deformation zone of the leading edge of the basin:tupitai wide syncline and heihui river closed anticline composed barrier-type folds,but the faulting is weak,the main fracture have Heihuijiang fault.The characteristics of the Ore-controlling structure of antimony mine:faults structures are very upgrowth,NW、NNW-trending thrusting faults are the main construction line of the mine.The trending faults’ scale is varying,fracture face mostly trend to SW or W,a few to NE,and they are all steep.Fault zones are obvious strong dense cleavage zones which caused stratum steeply dipping or upright,and formed strong broken zones,and with mineralization and hydrothermal metamorphism in some place.These reflected the mine had been strongly squeezed.Folds which formed in this period are caused by the faults,especially the Ore fabric structures of F5、F6、F7、F8、F9、F19.Later NE、NEE and EW-trending faults had formed in the mine,these broken of The scale is relatively small.They often move NW、NNW-trending faults to the left,the left-shift distance is about 100-200 m.The face of the fault serrated to indicate tensional nature. Tensional distance is about 2-3m,tension zones are broken zones.This period the mine be given shift-tensile force.The characteristics of the structure ore-controlling of The Bat Cave antimony deposit:Lancang River fault zone is ore-passing structures;NW、NNW-trending faults(F5、F6、F7、F8) and NE、NEE、EW-trending strike-slip faults(F9、F19) are ore-controlling structures;NW 、 NNW-trending structures and NE 、 NEE 、 EW-trending structures are important ore-storage structures.Stratums of the T3 m 、the T3 sh are important ore-storage stratums.Combined with regional tectonic evolution,the model of the ore-controlling structure of the area is:Lancang River faults zone of the Indosinian is a deep fault,it linked the deep hot brine and magmatic hydrothermal in deep crust. Orogeny and strike-slip movement in Yanshanian-Himalayan period formed mainly ore-controlling structures and ore-storage structures.In the driving forcethe deep hydrothermal moved up along the ore-passing structures(Lancang River fault and Heihui River fault),and filled in the ore-storage structures along the ore-controlling structures,such as fault fracture zone,and formed corresponding orebodies.