Abstract: Beiya Au-polymetallic mineral deposit is located at the southern segment of Jinshajiang-Honghe alkali-rich porphyry belt,it is the typical one of the mineral deposits metallogenesis related to related to alkali-rich porphyry.The geological characteristics and geochemical characteristics of layer-like Pb-Zn-Ag polymetallic deposit are researched in depth,the results show that:①the ore-hosting surrounding rocks of the Pb-Zn-Ag polymetallic deposit is consisted of the limestone within Beiya formation,middle triassic series,which is relatively rich in some mineralization elements such as Pb,Zn,Au etc and it is the advantageous ore-sourcing layer of Pb-Zn-Ag polymetallic deposit;②the ore-forming fluids of the Pb-Zn-Ag polymetallic deposit are NaCl-H₂O-CO₂ system characterized by medium-low temperature and salinity,which are derived from the magmatic hydrotherm differentiated by crystallization of the alkali-rich porphyritic body;③the contents of the S isotope of the ore-bodies is from -2.4‰ to +2.8‰,which indicates that the sulfur of this deposit has the same source from deep mantle as the porphyritic body,the partially strata sulfur is added in the later period,the Pb isotope analysis results show that the ore-forming materials are crust-mantle mixing in origin;④the specific Beiya formation carbonatite strata conditions,Beiya-Qinhe NNW-trending syncline tectonics and the magmatic activity of porphyry constitute the principal ore-controlling factors of the Pb-Zn-Ag polymetallic deposit.Based on the above research results,the genesis of mineral deposit of the Pb-Zn-Ag polymetallic deposit is analyzed,it show that the layer-like Pb-Zn-Ag polymetallic deposit is the results of alkali-rich porphyry differentiation hydrothermal mineralization,it is the periphery products of the Beiya alkali-rich porphyry-type gold polymetallic metallogenetic system.

Key words: Geological characteristics, Geochemical characteristics, Metallogenic materials, Ore-controlling factors, Genesis of mineral deposit, Metallogenetic system