Study On The Genesis Of Albite Rock And Deposits In Nanhegou And Tongmugou Copper Deposits In Zhongtiao Mountain

Zhongtiao Mountain is a major copper ore accumulation area in China.The copper ore bodies of Nanhegou and Tongmugou are basically in conformity with the stratum.They are layered and straggly distributed in the Zhongziqu Group and the Yujiashan Formation.Lithology and structural control.The metal minerals in the ore are chalcopyrite,pyrite,bornite,and pyrrhotite.The main ore-bearing rocks in the mining area are siliceous albite,carbonaceous schist,and impure dolomite marble.Although it has been mined for more than half a century,there are still differences in the genesis of the deposit,such as the theory of volcanic-sedimentary metamorphism,the theory of metavoltaic deposition metamorphism-regenerate hydrothermal fluidity,and the SEDEX.In this paper,through field investigations,rock and mineral identification,geochemistry of rock and ore,isotope chronology,and in-situ trace analysis,the geochemical characteristics of the ore deposits,ore-bearing rock series,various stages of metamorphism,and metallogenic ages have been studied.Sources of matter and ore-forming fluids identified ore-bearing siliceous albite and genesis of the deposit.The following main results have been obtained:(1)Analysis of carbon,hydrogen,oxygen,lead isotopes,and in-situ trace elements of sulfides show that the source of carbon has a multi-sourced character;the hydrogen-oxygen isotope composition of late veins has the characteristics of mixed metamorphic water and construction water;The source of lead is complex and has the characteristic of mixed lead.Traces of metal sulfides in situ show that both micro veins and vein mineralization are hydrothermal.(2)The siliceous albite is closely related to the deposit in space,and is generally in the same layered and straggling shape as the ore body.The experiment shows that carbonaceous schists are formed by metasomatism and alternation of brines,accompanied by fading.The process of potassium and sodium substitution is closely related to the mineralization of the early fine vein disseminated copper deposits.(3)The age data of rutile show that the mining area has experienced two regional metamorphic events.The ages of the two phases of rutile correspond to the ore-forming ages of carbonate and cerium isotopes,which are about 1.96 Ga and 1.86 Ga,respectively.Combined with the existing geological data,the mineralization ages of the two phases of the carbonate veins are the mineralization events corresponding to two metamorphic ages,respectively.Early carbonates are richer in heavy rare earth elements than later carbonates.(4)It is determined that the Nanhegou and Tongmugou copper deposits are deposit-metamorphic transformation copper deposits.