摘要：

Yutangba,located in the northern part of Shuanghe Town of Enshi City in SW Hubei Province,is an area of high-Se in China,and it is also the only site in the world where a sudden o ccurrence of Se poisoning took place.Selenium is present mainly in the bla ck Se-rich rocks(carbonaceous chert and carbonaceou s shale)of Upper Permian Maokou Formation which is 210m north of Yutangba.In Se-rich rock s,native selenium and copper(iron)selenide assemblages have been disc overed.These minerals include nati ve selenium,krutaite,klockmannite,mandarinoite,naumannite,Se-bearing pyrite,Se-bearing chalcopyrite and unidentified Fe-Se minerals.Of them,the assemblage of native selenium,k rutaite and klockmannite is mainly l ocated within the carbonaceous chert near the fault surface,and so are Se-bearing pyrite and Se-bearing chalcopyrite.However,the assemblage of native selenium and krutaite is just found i n carbonaceous mudstone.Mandarinoite and unidentified Fe-Se minerals can be found in the weathered carbonaceous chert that was exposed.Our results i ndicate that native selenium widely exists,and other selenium minerals and their assemblages are discrete in black S e-rich rocks and only found in some sp ecial sites.That Cu-Se minerals are easil y found also shows that copper may pla y a significant role in the geochemic al mobility and transformation of sele nium in the supergene environment of Yutangba.

展开