Geochemistry Of Sanli Pb-Zn Polymetallic Deposit,in Central Guangxi

The Sanli Pb-Zn polymetallic deposit,located in the Daming Mountain area,the central part of Guangxi Zhuang Autonomous Region,is hosted by Cambrian sandstone and shale.The ore body of this deposit as vein,lenticular as well as pinch-and-swell form extends along south-north direction.The mineral association of ores is sphalerite,galena and quartz with minor pyrrhotite,argentite and calcite.The hydrothermal alteration in this deposit is by characterized by silicification and local chloritization.In order to clarify utilizable associated elements and the source of ore-forming materials,trace and rare earth element and sulfur and lead isotope of sphalerite and galena from this deposit are measured.The results indicate that:(1)sphalerite is rich in Pb,Cd,As,Mn,Cu,In,Bi,Ni,Ag,Sb,Ti,Cr and Co;galena is abundant in Mn,Cu,Zn,Ag and Sb;and utilizable associated elements are Cd,In and Ag for sphalerite and Ag for galena,respectively;(2)the chondrite-normalized patterns of rare earth elements of sphalerite and galena from this deposit show right-incline shape and Y/Ho ratio display a large rang from 15.88 to 69.67 and a mean value of 34.94,which indicates that the ore-forming fluids are rich in F;(3)sulfur isotope of sphalerite and galena displays a narrow range with a ?34 SV-CDT value from-0.57‰ to 3.46‰ and a mean value of 1.52‰,implying a deep magma sulfur origin;(4)the lead isotopic compositions of sphalerite and galena are in accord with those of Late Cretaceous granite in the Darning Mountain area,which indicates that ore-forming materials(lead and metals)are derived from the Late Cretaceous magmatic rock.Together with regional metallogenic characteristics of magmatic hydrothermal polymetallic deposit,we deduce that it is likely that the mineralization age of Sanli Pb-Zn polymetallic deposit is Late Cretaceous and that the present ore bodies are distal ones of the deep skarn or vein ore body,thus suggesting a deep prospecting potential.