The Regularity Of Mineralization Alteration Facies Zoning And Ore Prospecting In Deep Part Of Huize Lead-zinc District

The super-large Huize lead-zinc ore district is one of the representative lead-zinc deposits in Northeastern Yunnan poly-metallic concentration district.Based on the study about geological characteristics of the deposit,this article uses the large-scale mapping method of structural alteration lithofacies to research the mineralization-alteration zoning and geochemical characteristics of deep deposit,to establish the mineralization-alteration zoning rule,and to calculate mineralization alteration index of different mineralization-alteration zones.On the base of above studies,the paper combines mineralization-alteration index with the study of tectonic geochemistry to predict the location of the orebodies.1)The Huize lead zinc district is strictly controlled by fault.The ore bodies are mainly hosted in the NE-trending compressive torsional fractural zone which in macro-crystalline dolomite of the Lower Carboniferous Baizuo Formation(C1b).Mineralization-alteration zoning on both sides of the ore body is obvious.With the decrease of the distance to the orebody,the intensity of mineralization alteration increases.Both distribution of the orebody and the alteration zone which is closely associated with the orebody are strictly controlled by the fault that formed during ore-forming period.It shows the close relationship among the tectonic,mineralization and alteration.2)The main alteration types are dolomitization,calcitization and pyritization.Mineralization mainly includes sphalerite and galena.According to the color of altered dolomite,the fabric of rock,the characteristics of petrology,the spatial location between the orebody and altered dolomite,the mineralization alteration intensity,etc.,the mineralization-alteration zoning of deep district,from wallrock to mineralized center,can be divided into five zones which are grayish-white coarse-grained crystalline dolomite(?),coarse-grained dolomite with pinholes(?),yellow coarse-grained crystalline dolomite(?),grayish white mineralized coarse-grained crystalline dolomite(?),orebody(?).From the wallrock to mineralized center,dolomitization,calcilization and pyritization show the change regularities of alteration intensity from weak to strong.Moreover,the number of the alteration zones in the area of peripheral prediction is relatively reduced,and the alteration intensity of each zone is weaker than it which closed to the orebody.3)Elemental mass balance method is used to calculate the migration characteristics of the components in each mineralization-alteration zone.The result shows that TFe,CaO,MgO,Pb and Zn almost keep transfer-in.Mineralization alteration index and growth index of the element transfer-in(Z)can be used to study the relationship between mineralization and alteration.Study shows that the values of mineralization alteration index(AI),pyritization index(AITFe),galena mineralization index(AIpb),sphalerite mineralization index and the growth index of the element TFe.Pb and Zn which keep transfer-in are increase with the decrease of the distance to the orebody.It reveals that mineralized intensity of lead-zinc and pyritization gradually strengthen.The dolomitization index of wallrock(AIMgo)is higher than it of the orebody.It displays that the wallrock suffered strong dolomitization.The index of mineralization and alteration has further showed the relationship between hydrothermal alteration and mineralization.4)The anomaly of mineralization alteration index,element Pb,element Zn and mineralized element association are used to extract the information of mineralization,which are consistent with the actual location of the orebodies.Meanwhile,the mineralization alteration index(AI>50%)can be used to indicate the mineralization of lead-zinc and pyritization.Through the comparison of three methods above,it is found that the mineralization alteration index is feasible for the extraction of mineralization information.Combined with the geological conditions of the district,the methods of mineralization alteration index,element Pb,element Zn and tectonic geochemical anomaly are used to ore prospecting in Xiaocaiyuan exploration area of 1584m level.Three prospecting targets are obtained.