| 湘西北下寒武统黑色页岩伴生元素研究新进展 |
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| 引用本文：.1995.New advances in the study of associated elements in lower Cambrian black shale of northwestern Hunan[J].Mineral Deposits,14(4):346~354 |
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| 中文摘要: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。 |
| 中文关键词:下寒武统 黑色页岩 海底喷气沉积 沉积盆地 |
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| New advances in the study of associated elements in lower Cambrian black shale of northwestern Hunan |
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| Abstract:The area in northwestern Hunan where the Lower Cambrian black shale is most enriched in associated elements Ni and Mo as well as platinum group elements is selected as the study area. A thorough investigation was made on Ni-Mo polymetallic deposits in Dayong County and Cili County 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 polymetallic deposits in Dayong and Cili show characteristics of exhalite and siliceous rock and should belong to typical exhalite in the aspects of chemical composition, trace elements (Se, As), Al- Fe- Mn triangular diagram and oxygen isotope composition (δ18OSMOW = 17.62‰ ~ 20.91‰); they have unique pipe-like rich orebodies (Ni+Mo= 5. 68‰ ～ 18. 93‰) as well as special element association of Ni, Mo, Cu, Zn, Se, As, Ba, Au, Ag and Pt group; metal sulfides in ores occur in gel-like form, suggesting rapid accumulation. δ34Sore = -6.7‰ ～ -17.6‰, δ34SSwall rock above ore = +3.1‰ ～ +24.8‰, indicating that ore beds are diametrically different from wall rocks; REE partitioning of ores shows weak negative Ce and Eu anomalies, belonging to weak LREE-rich type, with REE curve somewhat different from that of standard seawater; syngenetic breccia is well developed, and mineralization is obviously controlled by fault structure; ore deposits have two sets of metallogenic systems; in addition, Grade I, Grade II and Grade Ⅲ sedimentary basins might be distinguished on the basis of geological characteristics of siliceous rock as well as shapes and distribution of Mo-Ni polymetallic orebodies. All the available evidence shows that the enrichment and mineralization of associated elements Ni and Mo as well as platinum group elements in Lower Cambrian black shale in northwestern Hunan were related to submarine exhalation, and the ore deposits are of submarine exhalative-sedimentary type. |
| keywords:Lower Cambrian, black shale, submarine exhalation, sedimentation, sedimentary basin |
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