Quantitative analysis of mineralization-alteration index and deep prospecting significance of Qilinchang Pb-Zn deposit in Huize, northeastern Yunnan

The giant Huize Pb-Zn deposit is the most representative deposit of Pb-Zn polymetallic ore concentration area in northeastern Yunnan.In order to effectively extract and distinguish the mineralization-alteration information such as lead-zinc mineralization, pyritization and dolomitization in different mineralization-alteration zones, using large scale alteration petrographical mapping method, taking the typical levels of 1249 m as an example, to analyze the levels' mineralization-alteration types, altered rock composition, structure and other characteristics base on quantitative analysis of hydrothermal alteration index and growth index of element transfer-in.The results show that the main alteration types are dolomitization, calcitization and pyritization.Mineralization mainly are sphalerite and galena.Taking the ore body as the center, from footwall rock of ore body to ore body to hanging wall rock of ore body, the mineralization-alteration zoning shows that grayish white coarse-grained crystalline dolomite which is far from the orebody(Ⅰ), coarse-grained dolomite with pinholes(Ⅱ), beige coarse-grained crystalline dolomite(Ⅲ), grayish white coarse-grained crystalline dolomite which is closed to the orebody(Ⅳ), orebody(Ⅴ)and grayish white coarse-grained crystalline dolomite which is closed to the orebody(Ⅳ).The element TFe, CaO, MgO, Pb, and Zn in the different mineralization alteration zones almost keep transfer-in.Among them, the element TFe, Pb and Zn are the most obvious.Moreover, the quantitative calculation results of the mineralized alteration rocks' mineralization alteration index and the growth index of the elements transfer-in are consistent with the mineralization alteration zone in space.The values of alteration index(AI), TFe's alteration index(AI_TFe), and(Pb+Zn)'s alteration index(AI_Pb+Zn)are the highest in the Ⅴ zone while the value of MgO's alteration index(AI_MgO)is the lowest, clearly distinguished from other alteration zones; The values of Zn, Pb and TFe's growth index of element transfer-in(Z_Zn, Z_Pb and Z_TFe)are generally increasing from Ⅰ zone to Ⅴ zone, and the values of Z_Zn, Z_Pb and Z_TFe are significantly higher than those in surrounding rock.The study of mineralization alteration index reveals the relationship between hydrothermal alteration and mineralization, and also proves the rationality of spatial mineralization alteration zoning, which has guiding significance for deep exploration of similar deposits.