| 桂北九万大山-元宝山地区锡多金属矿床的地质特征和成矿系列 |
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| 引用本文：.1987.Geological Features And Minerogenic Series Of The Tin Polymetallic Deposits In Jiuwandashan-Yuanbaoshan Area,Northern Guangxi[J].Mineral Deposits,6(4):23~32 |
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| 中文摘要:本文从成矿系列角度出发，讨论了桂北九万大山-元宝山地区锡多金属矿床的地质特征和控矿因素，总结了矿化怍用在时间上的递变规律和矿床、矿体及元素在空间上的分布特点，并提出了该区的交代系列和交代建造，探讨了锡多金属矿床与其外围贱金属矿床之间的联系，最后建立了与雪峰期黑云母花岗岩有关的多金属矿床成矿系列的成矿模式。 |
| 中文关键词:桂北九万大山-元宝山地区 锡多金属矿床 成矿系列 交代系列矿化分带 |
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| Geological Features And Minerogenic Series Of The Tin Polymetallic Deposits In Jiuwandashan-Yuanbaoshan Area,Northern Guangxi |
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| Abstract:Jiuwandashan-Yuanbaoshan area in northern Guangxi is a new tin polymetallic ore-forming province developed since 1960s, and thirty tin deposits or occurrences have so far been found in it. According to mineral assemblages and genetic characteristics these deposits can be grouped into four types, i.e., greisen type, cassiterite-quartz type, tourmalite type and cassiterite sulfide type. The mineralizations are dated at 717-800 Ma. They are characterized spatially by deposit zoning (from the greisen type→tourmalite type→cassiterite-quartz type→cassiterite sulfide type) and element zoning (from Sn, W, U, As→Sn, As, Cu→Sn，Cu，Zn, Pd, Au) around the Xuefengian biotite granite intrusions (700-836 Ma), and temporally by multiperiodic activities consisting of cassiterite silicate period (comprising greisen stage, tourmalite stage and cassiterite-quartz stage) and cassiterite sulfide period (composed of arsenopyritte-pyrrhotite stage, chalcopyrite-pyrite stage and chalcopyrite-sphalerite-galena stage). The tin polymetallic mineralizations in the province constitute a typical minerogenic series associated with the Xuefengian biotite granite, In addition, the distribution of a series of Cu, Zn-Pb, Zn-Sb deposits outside the tin polymetallic deposits has been studied in this paper. This suite of base metal deposits used to be considered as hydrothermal deposits related to Yanshanian quartz porphyries, According to lead, sulfur and oxygen isotope studies, the minerogenic age of the deposits is determined as 670-790 Ma, and their ore-forming process is probably like this: the groundwater heated by the emplacement of the biotite granite formed a convection system, in which the base metals scattered in the country rocks were first leached out and then released from the hydrothermal solution to form orebodies in favorable fractures. It is thus considered that this suite of base metal deposits is likely to be a special part of the minerogenic series of tin polymetallic deposits associated with the Xuefengian biotite granite. Qwing to the complexity of the country rocks in the area, a series of metasomatic formations was formed when the magmatic hydrothermal solution responsible for the mineralization reacted with them. Based on the recent study, the metasomatic formations can be classified into five types, i.e., magncsio-metasomatic formation related to ultrabasic rocks, mafic one associated with basic-ultrabasic lavas, alkali-ferrous one connected with intermediate-basic rocks, alkali-siliceous one linked with clastic rocks ( siltstone and sandstone) and alkali-acidic one having to do with biotite granite. The common characteristics of these five metasomatic formations are: (1) the metasomatic intensity depends not only on the hydrothermal solution itself but also on the lithology and chemistry of the country rocks; in general, the more basic the country rocks are, the better the metasomatism; and (2) the quartz occurs in every metasomatic formation as a surplus phase, suggesting the close relationship between the mineralization-alteration and the biotite granite. |
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