The Study Of Occurrence Of Selenium And Ore Genesis Of The Yutangba Selenium Deposit In Hubei,China

The Yutangba deposit, located in Hubei Province, has been commonly recognizedas the only independent selenium deposit in China. Tectonically, it located in thenortheastern part of upper Yangtz platform. Se-bearing bodies are concordantly hostedin the carbonaceous siliceous rocks and carbonaceous shale of the Lower PermianMaokou Formation, occurring as stratoid and lenticular forms.The main minerals comprise quartz, chalcedony and carbonaceous rocks withminor pyrite, limonite, chalcopyrite etc. Barite, galena, sphalerite, ferroselite andunknown selenium mineral were also identified with SEM. Generally, Se exists asindependent minerals with mainly three kinds of selenium minerals: the first one isferroselite distributed in unknown Fe-Se compounds with strip forms and small grainsranging from1to4μm; the second one is native selenium, mainly occurred in quartzgrains between the carboniferous siliceous rocks and silicate-bearing shale as tabular,columnar and xenomorphic granular; the other unknown Fe-Se compounds are mainlypresented in the border or scattered inerior of siliceous rocks with various grain sizesranging from2to200μm. Also, some minor Se are occurred as isomorphous series inpyrite and quartz.Collection and reanalysis of previous geochemistry data indicates Se is mainlyderived from hydrothermal activities with minor probably associated with biologicalactivities. Shallow sea facies euxinic basin depositional setting in late Permiancreated favorable conditions for the primary deposition of Se-bearing formations. Inthe strong reducing environment of the later diagenetic stage, Se were redissolved andinfiltrated in the permeable rocks and then deposited in the suitable place leading tothe formation of the primary Se-rich formations. Post regional activities enriched thehighly concentrated Se-rich formation to an exploitable grade and bought to theformation of the Yutangba deposit.