Geological Characteristics And Genetic Analysis Of The Lijiashan Vanadium Deposit In Pengze County,Jiangxi Province

The vanadium deposits discovered in Jiangxi Province are mainly distributed in Xiushui,Wuning,Yongxiu,Duchang,Pengze in the north and Dexing,Shangrao in the northeast of Jiangxi Province.In this paper,the geological characteristics of the Lijiashan vanadium deposit in Pengze County,Jiangxi Province are discussed.Then the major,minor and rare earth elements of the black shales of the lower Cambrian in the deposit are systematically studied.The sedimentary environment,tectonic background of the source area and the origin of the black shale are further discussed.The results show that the Lijiashan vanadium deposit in Pengze county is located in the south margin of Jiujiang depression in the west of the Lower Yangtze block.Vanadium ore bodies mainly occur in dark gray ~ gray black carbonaceous shales and silt and carbonaceous bearing mudstone in the Hetang Formation at the bottom of Cambrian system.The vanadium in ores mainly occurs in vanadite mica minerals(including some illite hydromicas),followed by iron oxide,kaolin,and a small amount of tourmaline and garnet.Three main orebodies dip to 330 ~ 340 °with dipping angles of 25 ~ 45°.The thin layered orebodies are 900 ~ 1100 m in length,1.06 ~ 13.73 m in thickness.The V2O5 content controlled by single engineering is generally 0.7 ~ 1.41 wt.%.The industrial ore bodies are 14.148 million tons,with the average grade of 0.87%,and the accordingly V2O5 oxide amounts are 122499 tons.Si O2 content in black rock series ranges from 50.52 to 82.58%,with an average of65.85%.Compared with the average abundance value of crustal elements,the enriched elements are mainly chalcophile Cd,Zn,In,Tl,Sb,Pb,Bi and lithophilic elements Sc,V,Cr,U,followed by siderophile elements Mo,Ni.The total amount of rare earth elements is low and show a great variation.LREE/HREE ratios range from1.21 to 5.30.The delta Eu is 0.50 ~ 1.64,with an average of 0.86,which is a weak negative anomaly.Delta Ce is 0.36~0.81,with an average of 0.60,showing a strong negative anomaly.The fractionation degree of light rare earth elements is high,which belongs to light rare earth enrichment type.The source of sedimentary materials is mainly terrestrial and heated meteoric water was involved with the ore-forming process.The depositional environment was characterized by warm and humid climate,and was characterized by abyssal and abyssal anaerobic reduction environment.The sedimentary tectonic environment is mainly ocean island arc and continental arc.