Genesis Of Pb-Zn Deposit In Longjing Street,Guizhou Province

Guizhou Longjing Street lead-zinc deposit is located on the Bao(Jing)-Copper(Ren)-Yu(Plate)-Kai(Li)-San(Dou)Deep Great Fault Zone in the transition zone between the Yangtze Platform and South China Fold Belt.The deposit is mainly produced in the dolomite formations of the Cambrian Qingxudong Formation.This paper discusses the characteristics of ore body production,the ore material composition,structure and structure,trace(mineralization)elements,rare earth elements,sulfur isotopes and other geochemical characteristics,discusses the sources of ore-forming materials and the metallogenic environment,and analyzes the genesis of the deposits.Through the research,the following points are obtained:(1)The PB-Zn ore body is layered and lenticular,and the ore body is consistent with the strata.The mining area distributes ?,?two orebody,the thickness is 25~60m,4.09~15.30 m respectively.(2)ore mainly by sphalerite,Galena,smithsonite,water zinc ore,lead alum,Cerussite and other mineral and dolomite,pyrite,hematite,magnetic hematite and pyrite and other gangue mineral composition.The ore has the structure of self-shape,half self-shape,its shape,metasomatism residue,knead wrinkle and comb shell shape,veins,net veins,angular gravel,star dot,dense disseminated,clumps,crust-like and porous.(3)According to the shape and production of orebody,combined with the structure of ore,mineral symbiosis and the interspersed and metasomatism between minerals,the formation process of ore is divided into two metallogenic periods such as hydrothermal stage and apparent stage.(4)trace(metallogenic)elements,rare earth elements,and minerals in the lead-zinc deposit of Longjing Street.Studies on the geochemical characteristics of sulfur isotopes,the ore-forming minerals from the deposits are mainly from surrounding rocks(dolomite).(5)The physicochemical typomorphic characteristics of sphalerite in the mining area,the geochemical characteristics of ore and the sulfur isotopic compositions,which indicate that the metallogenic environment of the deposit is medium-low temperature and shallow environment.(6)The formation process of the deposit is roughly as follows: from the atmospheric precipitation or under water seepage,along Longjing Street deep Big Fault zone,the fault and the small fissure zonepermeate,under the driving of the gravity gradient,flow to the deep part of the fault zone,during which the useful components of the surrounding rock(S,Zn,PB etc)are continuously leached and activated to form the ore-bearing hydrothermal solution.At the same time,the tectonic squeezing caused by the multi-stage activity of the deep fault zone in Longjing Street is releasing the pore water in the deep heat flow or Deep rock.The released hot fluid continues to move upward along the large fault zone,fault and fissure in the process of tectonic stress,extracting useful components from the surrounding rock in the course of migration,forming deep ore-bearing hydrothermal fluids,The mixture of deep ore-bearing hydrothermal solution and ore-bearing hydrothermal solution in the upper part formed a mixed ore-bearing hydrothermal solution,and then enriched the integrated ore by filling and metasomatism in advantageous lithofacies(dolomite)and tectonic(interlayer fracture,interlayer fissure,etc.).It is concluded that the Pb-Zn deposit in Taijiang Longjing Street,Guizhou Province,is a sedimentary-reformed layer-controlled deposit.