| 盆地流体动力学演化及其成矿效应——以广东富湾-长坑银金矿床为例 |
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| 引用本文：.2002.Dynamic Evolution of Basin Fluid and Its Metallogenic Effects: A Case Study of Fuwan-Changkeng Silver-gold Deposit, Guangdong Province [J].Mineral Deposits,21(3):223~231 |
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| 基金项目:国土资源部重点科技攻关项目(9501103)和国家杰出青年基金(49825531)项目 |
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| 中文摘要:文章以广东富湾-长坑层控银金矿床为实例，基于各阶段盆地中温度场、压力场和流动场的动力学演化过程与成矿效应的研究，发现盆地流体转变为成矿流体具有漫长的演化与更迭历程；构造演化和盆地的沉积充填特征，不仅直接影响着流体在盆地中的流动样式，而且直接影响着成矿物质空间存在形式的变化以及“流体_岩石”体系中各要素间的再分配。流体的大规模活动及大型矿床的形成与大幅度的构造运动、沉积作用、岩浆活动、火山活动等宏观地球动力作用有关，盆地边缘沟通深部的垂向断裂与浅部不整合面_侧向断裂交汇地段是成矿物质堆积的最佳场所。 |
| 中文关键词:盆地 流体 成矿作用 动力学 金矿 银矿 |
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| Dynamic Evolution of Basin Fluid and Its Metallogenic Effects: A Case Study of Fuwan-Changkeng Silver-gold Deposit, Guangdong Province |
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| Abstract:The Fuwan-Changkeng silver-gold deposit, a stratabound super-large deposit discovered in South China in 1990's, occurs in the detachment zone along the unconformable surface between the underlying Carboniferous limestone and the upper Triassic shale and sandstone. Previous study conducted by the authors shows that the ore-forming fluid originated from basin formation fluid. In this paper, the evolution of the temperature-pressure field and the fluid regime were simulated spatiotemporally on the basin scale, and the process of the mobilization, transportation and deposition of the ore-forming matters by the basin fluid was discussed. The results of basin modeling indicate that the formation, the movement and the thermodynamic evolution of the ore-forming fluids are controlled by the tectonic evolution and the sedimentary filling characteristics of the basin. The fluid migrated from formation water to hydrocarbons-bearing fluid and to ore-forming fluid in the deep layers of the basin under high temperature and pressure, and migrated from ore-forming fluid to residual fluid with low content of metals in shallow surroundings. Gold and silver were accumulated and concentrated by basin fluid from the depth at high temperature and pressure, moved upward under the driving force of the high-speed compaction, and migrated to shallow places and precipitated at a suitable location with relatively low temperature and pressure. The fluid regime changed with the evolution of the basin. Large amounts of hot fluid moved from deep basin to the shallow rapidly at the stage when the basin subsided with high burial rate, while large volume of cold surface water flowed from platform to basin at the uplift. Thus the mixture of hot ore-bearing fluid with deep and surface cold water could have occurred in the main pathways such as faults and detachment zones during the shifting from subsidence to uplifting or vice versa , which might lead to the mineralization and the formation of the deposit. The large deposits respond to the joint forces of basin subsidence and magmatic activity. |
| keywords:basin, fluid, dynamics, mineralization, gold deposit, silver deposit |
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