Genesis And Resource Potential Of Pb-Zn Deposit In The Heweitan Area,Hetian County,Xinjiang

The research area is located in the middle section of West Kunlun mountain in southwest of Xinjiang Uygur Autonomous Region,spreading in NW-SE direction,and is an important part of Karakoram metallogenic belt.In recent years,with the development of mineral exploration,the prospecting of Pb and Zn in the area has achieved many results.This paper focus on the geology and mineralization characteristics of Pb-Zn deposits in Heweitan area,Hetian County,Xinjiang,analyzes the source of metallogenic materials,analyzes the genesis of the deposit,summarizes the metallogenic regularities,and carries out metallogenic prediction in combination with isotopic geochemistry characteristics,and obtains the following main understanding:The sedimentary strata formed under the epicontinental sedimentary system from late Paleozoic to Mesozoic in the study area provide the main materials for the formation of Pb-Zn deposits.The massive thrust nappe structure occurred in the extrusion stage of Paleogene provides sufficient ore-hosting space for the enrichment of Pb-Zn deposits in later period.The normal fault fractures formed in the extensional stage of the Neogene provide space for the accumulation and fluid migration of Pb-Zn ore,and the ore bodies were formed in the tectonic regime transformation stage which from compression to extension.The Pb-Zn deposits in the research area are concentrated in Mesozoic marginal sedimentary basins.The ore-bearing formations are Jurassic Longshan formation and Cretaceous Tielongtan Formation,and the ore-bearing rocks are limestones and dolomitic limestones.The NW deep fault and its secondary fault system control the output and distribution of Pb-Zn orebodies,which is the main ore-conducting and ore-hosting structure.The NW fault has the function of reforming the ore body.The ore minerals are mainly zinc and lead-white ore,followed by galena,lead-vanadium and sphalerite.The alteration of wallrock is hematite,limonite and carbonate.The Pb-Zn deposit has undergone two metallogenic stages,the hydrothermal sulfide stage and the metasomatic non-sulfide stage.The S isotopic characteristics of the ore in the research area indicate that S is mainlyderived from sedimentary rock strata,with the addition of surface fluids.Pb isotope indicates that Pb comes from the upper crust,which is consistent with Pb and Zn in the wall rock.The characteristics of carbon and oxygen isotopes indicate that the ore-forming fluid originates from carbonate rocks and is related to decarbonation and carbonate karstolysis rather than magmatic hydrothermal.The Pb-Zn deposits are controlled by the dual factors of "formation + structure",and the mineralization has gone through the process of "source layer,hydrothermal sulfide,metasomatic non-sulfide".The mineralization geological process belongs to non-magmatic hydrothermal type,and the genetic type is tectono-hydrothermal-metasomatic Pb-Zn deposits.The research area were divided into two ? type Pb-Zn metallogenic prospect areas,and four Pb-Zn prospecting target area.Through the evaluation of resource potential,it is predicted that 4.3531 million tons of Pb-Zn resources will be produced in the depth of 260 meters.