Genesis Study Of Liudou Gold Deposit And Yindonggou Silver-polymetallic Deposit In Western Wudang Area

In this paper, the Liudou gold deposit and the Yindonggou silver polymetallic deposit in the western Wudang area, southern Qinling orogenic belt are taken as the research cases. The comparativestudy has been done from different aspects, such as mineral geology characters, stableisotopes, fluidinclusion features, and so on.The liudou gold deposit is located in the western wudang area and in north side of the Shiyan-Baihe Fault. The North South trending detachment is the main ore governing structure, and divides the Yaolinghe Group in the below and the Doushantuo Group on top of which. The stratiform-likeand enticularorebody is controled bysuperimposed brittlefracture, trending north-south, north west and north east, etc. The main ore body types include the fracture alteration type and the quartz vein type. Isotope data of microvein minerals indicate that the composition of ore-forming fluid is basically stable and the initial ore-forming fluid is metamorphicfluid, and then, to some degree, meteoricwaters join in.The shape of fluidinclusion is commonly regular, formed in the condition of moderate temperatures(210-220℃) and moderate pressures(140-150 Mpa).The Yin Donggou silver polymetallic deposit is located in the western wudang area and in south side of the Shiyan-Baihe Fault. The stratum is mainly green schist facies metamorphic rocks of Wudang group and the main ore governing structure is the Yin Donggou Anticline. The deposit is controlled by Yin Donggou Anticline and ductile shear zone. The bodies exist in the axial plane cleavage, the core of anticline, which is Westward pitch, side in plane, typical zoning in vertical, also Ag-Au ore body is upper and Pb-Zn ore body is lower. The main Mineralization is among three stages at one time. The I stage is quartz-Pb-Zn mineralization stage; the Ⅱstage is Ag-Au mineralization sub-stage, with the Ⅱ1 is quartz-Ag-Au mineralization stage; the Ⅱ2 is quartz- Ag-Au(including Pb-Zn)mineralization sub-stage; the Ⅲstage is Quartz- iron dolomite slightly mineralization stage.Then the body is tectonically strongly reworked, showing boudins,scrunch and veins cutting by each other.Fluid inclusion is common and type diversified, formed in an environment of medium temperature(280~290℃), medium pressure 200~220Mpa, and 11.5~12.5km depth.The liudou gold deposit is orogenic gold depositand themineralogeneticage is is early Indosinian The Yin Donggou silver polymetallic deposit is Mesothermal vein-type deposit controlled by ductile shear zone,which is similar asorogenic-type Ag deposit,and the mineralogeneticage is is late Indosinian.