渔塘坝硒矿床多元素富集与沉积环境

对采自湖北西部渔塘坝二叠系独立硒矿区的硅质岩和页岩样品进行了元素测试（微量元素、总铁、总有机碳、总硫），分析了该区域的多元素富集及沉积环境。该区域V、Cu、As、Cd、Tl、Se、Mo、V、 Sb、 U、Ag、 Cr、Ni相对富集, Ba、Hf、Ta、W、Pb、Th相对贫化或亏损。全硫—全铁（TS—TFe）的关系表明页岩及部分硅质岩的S/Fe比值均大于1.15，说明有过量的硫存在，可能为有机硫或为其他亲硫元素沉淀提供条件。TOC—TS—TFe三角图及V/(V + Ni)表明该区域的岩石形成于缺氧或静海相环境。U/Th、Zr—Cr、P—Y等微量元素地球化学参数表明该区域有热水沉积的存在。通过对微量元素可能的来源研究分析，该区域的微量元素可能存在多种来源:热水来源、海水沉积、峨眉山玄武岩。

Enrichment of Multiple Elements and Depositional Environment of Selenium-rich Deposits in Yutangba, Western Hubei

Total organic carbon(TOC),and total sulfur(TS),total iron(TFe)contents were analyzed in the siliceous rocks(bedded chert)and shales sampled from the selenium deposit of Yutangba,western Hubei,based on which the mechanism of enrichment of multiple elements and depositional environments(i.e.,redox conditions)are documented.The enrichmental factors of V,Se,Cd,Sb are larger than 10;those of Co,Ni,Cu,Zn,Ge,As,Tl,U are in the range between 1 and 10.The S/Fe ratios are generally greater than 1.15,suggesting that surplus sulfur may have occurred,which may have accelerated the precipitation of organic-bound sulfur and some chalcophile elements.The triangular diagram of TOC-TS-TFe,the ratios of V/(V Ni),and the relationship between some elements and TOC suggest that the selenium-rich black rocks(black shales and bedded chert)were deposited in anoxic and euxinic environments.In addition,some geochemical parameters,such as U/Th ratios,Zr-Cr,P-Y abundances in the sediments,suggest that hydrothermal processes might have occurred during the deposition.Multiple sources of trace elements,i.e.,marine,hydrothermal inputs and Emeishan basalts,were likely responsible for deposition of the selenium-rich deposits at Yutangba,western Hubei.