The Ore Controlling And Discussion On The Genesis Of Lanmugou Gold Deposit , In Xunyang, Shanxi

Lanmugou gold deposit is located in the middle section of Luqu-Xunyang Indosinian fold belt,South Qinling tectonic zone,Qinling orogenic belt.It belongs to the South Qinling thrust nappe tectonic rock slice of Qinling plate.Previous studies mainly focused on the geological feature,mineral deposit genesis and ore – controlling factors of the gold mine in the metallognic belt west to Lanmugou area,few researches could be found on the gold mine Lanmugou area.This paper analyzes the regional metallogenic background and Lanmugou gold deposit in details,employs various tools,such as the mineral deposit geological survey,microscopic observation,deposit geochemistry and isotopic dating,identifies the orebody distribution,host structure,fluid sources,the potential material sources,metallogenic process.Observations on the deposit geology reveal that the mining area mainly exposed the neritic facies clastic rock of the Lower Silurian second lithologic section.This area mainly are three sets of fault systems are observed in the mine,including nearly east–west-striking set,north-west-striking set and south-north–striking set,.Lanmugou gold deposit is overall controlled by Heihumiao ductile shear zone.The mineralization and alteration control the spatial distribution of ore and mineralization body.Gold ore bodies are mainly hosted in altered quartz biotite schist belt and they occur along the strata.S isotope data show that sulfur in sulfides is derived from sulfate deposited in seawater.Pb isotope and REE reveal that the mineralization material is from sedimentary strata.Pb data reveal some mantle source.H-O isotopes data indicated that the ore-forming fluid have many source,and it is mainly related to construction water and deep sources.The Re-Os isotopic model age of pyrite is(202 ± 20)Ma,indicating that mineralization age of the Lanmugou gold deposit falls into the Late Triassic.The results of study indicates Lanmugou gold deposit is on the basis of terrigenous elastic sedimentary rocks that possess higher gold background formed in rift environment,and through transforming by regional deformation,metamorphism and multiphase ductile-brittle shear tectonic,finally located in thrust nappe shear zone and mineralized.It belongs to a sedimentary metamorphic fine grained disseminated gold deposit producing in ductile shear zones.