| 右江幔隆与金矿成矿关系 |
| 张朝晖
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| 1993
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| 学位授予单位 | 中国科学院地球化学研究所
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| 学位授予地点 | 中国科学院地球化学研究所
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| 学位名称 | 博士
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| 学位专业 | 矿床地球化学
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| 关键词 | 右江幔隆
微细浸染型金矿
幔隆机制
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| 摘要 | 滇黔桂地区是微细浸染型金矿的主要产区之一。前人对滇黔桂地区微细浸染型金矿所作的大量地质地球化学工作，为进一步了解成矿规律判定了基础。目前研究中尚存在一些问题，如区域成矿规律是怎样的，找矿方向向何处扩展和成矿边界在哪里等等。从幔隆机制的观战出发，笔者较为详细地讨论了右江幔隆机构及其地质、地球化学和地球物理表现形式，和幔隆的时空演化史，探讨了它与微细浸染型金矿的内在联系。幔隆早期，地幔物质上涌，地壳拉张、变薄，大量幔源富金物质上升，奠定了该区矿源层的基础，形成右江大断裂及两侧的深断裂。幔隆发展晚期，转变为挤压环境，两侧深断裂重熔，形成酸性岩浆及后期多次活动表现为隐伏花岗岩体，为矿化提供了热源和部分成矿物质使矿源层中的金活化、转移，在有利的岩相地球环境和构造部位富集成矿。隐伏花岗岩带控制了微细浸染型金矿的分布。由此可见，幔隆从早期到晚期，控制了矿源层的初始富集及最终成矿，和微细浸染型金矿化存在密切的内在联系。笔者较为详细地对比了美国西部微细浸染型金矿及大盆地的地质、地球物理和地球化学特征，认为大盆地也是一幔隆机构，和各类金矿有密切的内在关系。这对滇黔桂地区找矿具有启发意义。笔者认为，右江幔隆金成带的成矿模式表现在水平方向上，随莫霍面等深线由南东向北西的倾没，岩体出露或隐伏深度不同，而表现出矿床组合有规律的演变；在垂直方向上，则体现为由上而下，为微细浸染型金矿 → 石英脉型金矿→矽岩型铜金矿→斑岩型铜金矿（尚未发现）的“多层楼”模式。桂西北地区则是寻找这种模式的希望地区。当前微细浸染型金矿的找矿方向应集中在两条隐伏花岗岩带上。重力异常+航磁异常+化探的Au、As、Sb异常是桂西北地区该类金矿最重要的找矿标志。根据幔隆机制可认为扬子地台周围地幔隆赵区是寻找该类金矿的远景区。 |
| 其他摘要 | The gold triangle in the border area of southeastern Yunnan, southwestern Guizhou and northwestern Guangxi is one of major gold-producting areas of micro-grained disseminated deposits. Previous work on geology, geophysics and geochemistry in this area laid a foundation for a better understanding of the laws of metallogenesis. But there are still some problems, for example, laws of regional metallogenesis and exploration, and areas of metallogenesis, etc. In view of mantle uplift, the auther discusses in detail the mechanism of Youjiang mantle uplift and its geology, geophysics and geochemistry, as well as its temporal and spatial evolution. At the early stage of mantle uplift, with the mantle uplifting and the crust pulling apart, the crust became thinner and mantle-derived gold-rich materials found their way upwards, contributing a lot to the original source bed. Major faults such as Youjiang and Binyang-Bama-Luolou faults came into being. At the late-stage development of mantle uplift, a compressional environment was created. Remelting took place in the major faults, forming acid-magma. The anatexis of acid-rock at later stages provides a heat source for metallogenesis. Gold in the early source bed can be mobilized, transporated and precipitated in favorable lithosfacies and structural loci. It is thus evident that mantle uplift controls initial Au enrichment of the source bed and final metallogenesis, there is an inner link between them. After detailed comparison with the Great Basin in western USA with respect to its geologic, geophysical and geochemical data and Au mineralization, the author considers that the Great Basin is also an area which underwent mantle uplifting. Mantle uplifting seems to have genetic connections with gold deposits. From the preliminary work in northwestern Guangxi in conjunction with the available data, the author holds that northwestern Guangxi is a possible target area for prospecting "multilayered" ore deposits. Exploration for micro-grained disseminated gold deposits should be focused on the two concealed granite belts. Gravity anomaly + aeromagnetic nomaly + Au, As, Sb anomaly will be important and effective indicators. The author suggests that the surroundings of the Yangtze Platform, especially mantle uplift areas, are potential for disseminated gold deposists. |
| 页数 | 75
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| 语种 | 中文
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| 文献类型 | 学位论文
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| 条目标识符 | http://ir.gyig.ac.cn/handle/352002/3908
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| 专题 | 研究生_研究生_学位论文
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推荐引用方式
GB/T 7714 |
张朝晖. 右江幔隆与金矿成矿关系[D]. 中国科学院地球化学研究所. 中国科学院地球化学研究所,1993.
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