歙县鲍坑地区金矿成矿地质条件及找矿远景分析
Metallogenic conditions and ore-prospecting of gold deposit in Baokeng area, Shexian County
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摘要: 安徽省歙县鲍坑地区位于歙县—三阳坑Cu-Pb-Zn-Au-Ag多金属成矿远景区南西部,成矿地质条件优越。通过在该区开展地质填图、1∶1万土壤地球化学测量及槽探等地质工作,进一步研究区内金矿的成矿条件和矿床成因。结果表明:鲍坑金矿主要位于变形明显的新元古代昌前岩组中,地球物理特征总体为重高磁低,矿体产于呈NE向展布的Au、As、Sb化探异常中;矿床类型为剪切构造控制的热液型。提出在构造强烈的金低背景浅变质岩层位区,在剪切构造巨大的活化作用下,Au元素才可能富集成金矿的新认识,为该区在韧性剪切带中寻找金矿提供了依据。Abstract: The Baokeng area is located in southwest Shexian-Sanyangkeng Cu-Pb-Zn-Au-Ag polymetallic metallogenic prospective area, and hosts superior metallogenic conditions. The metallogenic conditions and genesis of gold deposit in Baokeng area are discussed through geological mapping, 1:10 000 scale of soil geochemical survey and trenching. The results show that Baokeng gold deposit is mainly located in the Neoproterozoic Changqian Formation which underwent obvious deformation and are generally characterized with high gravity and low magnetism by geophysical exploration, and that the ore bodies occur in the NE direction geochemical anomaly rich in Au, As and Sb. The deposit is hydrothermal type controlled by shear structure.We propose that the gold may be enriched by great activiation of shear structure in low-gold-content, low-metamorphic strata with intensive structural activity. This understanding provides a theoretical basis for gold prospecting in ductile shear zone of this area.