贵州碳酸盐岩型铅锌矿床地质特征与容矿机理

Geological characteristics and ore-hosting mechanism of the carbonate-hosted type lead-zinc deposits in Guizhou Province,China

贵州铅锌矿床主要集中成群成带分布于东部和西部,查明的铅锌矿产地中碳酸盐岩型铅锌矿占82%,探明资源储量占总量的90%以上。贵州碳酸盐岩型铅锌矿床赋矿层位多,自新元古界震旦系灯影组至上古生界二叠系栖霞-茅口组均有产出。年代学研究表明,铅锌成矿时代明显晚于赋矿地层时代,后生成矿特征显著,矿床成因应属MVT矿床。在区域地质、地球化学背景及典型矿床地质特征分析基础上,剖析碳酸盐岩的形成、特性及其与铅锌成矿的内在联系,揭示富铅锌成矿流体在碳酸盐岩中的迁移、富集、成矿是受区域构造活动及构造发育程度、流体来源及组成特征、物理化学条件、水岩反应、深部热卤水与赋矿层位中富S流体混合等多种因素控制。通过区域铅锌成矿规律的总结,将对找矿预测具有重要指导意义。

The lead-zinc deposits in Guizhou Province are mainly distributed in swarms in the eastern and western Guizhou.The carbonate rock-hosted lead-zinc deposits account for 82%of the prospected lead-zinc resources and over 90%of the total proved lead-zinc reserves in Guizhou Province.Many carbonate-hosted lead-zinc deposits are distributed in various strata including the Neoproterozoic Sinian Dengying Formation,and the upper Paleozoic Permian Qixia and Maokou formations.The chronological studies show that the lead-zinc mineralization ages are obviously later than those of host strata.The deposits have obvious characteristics of epigenetic metallogeny,and they belong to the MVT-type deposit.In this paper,based on the analysis of regional geology,geochemical background and geological characteristics of typical Pb-Zn deposits,we have discussed the internal relationship between formation and characteristics of carbonate rocks and the lead and zinc mineralization,and have revealed that the migration,enrichment,and mineralization of lead-zinc enriched ore-forming fluids in carbonate rocks are controlled by various factors including the regional tectonic activity and structural development degree,fluid source and compositional characteristics,physicochemical conditions of the fluids,the water-rock reaction,and the mixing of deep hot brine fluid and S-rich fluid in the host layers.The comprehensive summary of the regional Pb-Zn metallogenic regulation will provide significant guidance for the Pb-Zn ore prospecting prediction.