湘西北下寒武统黑色页岩伴生元素研究新进展  

NEW ADVANCES IN THE STUDY OF ASSOCIATED ELEMENTS INLOWER CAMBRIAN BLACK SHALE OF NORTHWESTERN HUNAN

作　　者：李有禹[1] 

机构地区：[1]湘潭矿业学院

出　　处：《矿床地质》1995年第4期346-354,共9页Mineral Deposits

摘　　要：湖南大庸慈利的镍钼多金属矿床是湘西北下寒武统黑色页岩中伴生元素镍钼及铂族元素等富集最好地段。该矿床中的硅岩应属典型的喷气岩；特殊的筒状富矿体（Ｎｉ＋Ｍｏ＝５．６８％～１８．９３％），以及Ｎｉ、Ｍｏ、Ｃｕ、Ｚｎ、Ｓｅ、Ａｓ、Ｂａ、Ａｕ、Ａｇ、Ｐｔ族元素特殊组合；矿石中金属硫化物呈胶状产出，显示快速堆积特征。已有的证据表明，湘西北下寒武统黑色页岩中伴生元素镍钼及铂族元素的富集与成矿，与海底喷气（流）作用有关，其矿床成因应为海底喷气沉积矿床。The area in northwestern Hunan where the Lower Cambrian black shale is most enriched inassociated elements Ni and Mo as well as platinum group elements is selected as the study area.Athorough investigation was made on Ni-Mo polymetallic deposits in Dayong County and CiliCounty in such aspects as strata,structure,ore deposit geology and geochemistry;as a result,abundant geological data was accumulated and new understanding was reached.Ni-Mo poly-metallic deposits in Dayong and Cili show characteristics of exhalite and siliceous rock and shouldbelong to typical exhalite in the aspects of chemical composition,trace elements(Se ,As),Al-Fe-Mn triangular diagram and oxygen isotope composition(δ￣(18)O_(SMOW) = 17.62‰～20. 91‰);theyhave unique pipe-like rich orebodies(Ni+Mo= 5. 68‰～18.93‰)as well as special element as-sociation of Ni,Mo,Cu,Zn,Se,As,Ba,Au,Ag and Pt group;metal sulfides in ores occur ingel-likeform,suggestingrapidaccumulation. δ￣(34)S_(ore)=-6.7‰～-17.6‰,δ￣(34)S_(wall rock above ore)=+3.1‰～+24.8‰,indlcating that ore beds are diametrically different from wall rocks;REEpartitioning of ores shows weak negative Ce and Eu anomalies,belonging to weak LREE-richtype,with REE curve somewhat different from that of standard seawater;syngenetic breccia iswell developed,and mineralization is obviously controlled by fault structure;ore deposits havetwo sets of metallogenic systems;in addition,Grade Ⅰ,Grade Ⅱ and Grade Ⅲ sedimentarybasins might be distinguished on the basis of geological characteristics of siliceous rock as well asshapes and distribution of Mo-Ni polymetallic orebodies. All the available evidence shows that theenrichment and mineralization of associated elements Ni and Mo as well as platinum group ele-ments in Lower Cambrian black shale in northwestern Hunan were related to submarine exhala-tion,and the ore deposits are of submarine exhalative-sedimentary type.

关 键 词：下寒武性 黑色页岩 沉积盆地 伴生元素 

分 类 号：P588.311[天文地球—岩石学]