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为了揭示矾山地区中生代花岗岩的成因、侵位时间及其与成矿的关系,在岩石地球化学研究基础上,进行锆石U-Pb-Hf同位素测试,并与紫金山矿田进行对比,为本区找矿预测提供依据.矾山地区花岗岩具有高钾、高碱、富硅、低钛等特征,富集轻稀土元素,具弱-中等负铕异常.富集大离子亲石元素(K、Rb、Th等),亏损高场强元素(Nb、Ta、Ti等),具有板块俯冲后伸展环境特征.对花岗岩岩体进行锆石U-Pb测年,获得了110Ma的年龄.花岗岩与花岗闪长岩Hf同位素特征相似,ε_(Hf)(t)为-3.1~1.6,T_(DM2)为1 066~1 366Ma,说明花岗岩主要来源于中元古代地壳物质的重融,同时显示出壳幔混合作用的特征.矾山地区与紫金山矿区构造、成岩、成矿特征相似,具有“紫金山式”铜金矿找矿潜力.
In order to reveal the genesis and emplacement time of Mesozoic granites and their relationship with metallogenesis in the Fanshan area, zircon U-Pb-Hf isotope tests were conducted on the basis of lithogeochemical research and compared with that of the Zijinshan orefield The results indicate that the granite in the Fanshan area is characterized by high potassium, high alkali, silicon rich and low titanium, enriched in light rare earth elements and weakly to moderately negative Eu anomalies. The enrichment of large ion lithophile elements (K , Rb, Th, etc.), depleted high field strength elements (Nb, Ta, Ti, etc.) with extensional environment characteristics after subduction of the plate.The zircon U-Pb dating of granite was obtained and the age of 110 Ma was obtained. The Hf isotopic characteristics of granodiorite are similar, ε_ (Hf) (t) is -3.1 ~ 1.6 and T_ (DM2) is 1 066 ~ 1 366Ma, indicating that the granite mainly comes from the re-melting of the Mesoproterozoic crustal material, The crust-mantle-mixing feature.The structure and diagenesis and metallogenic characteristics of the Fanshan area and the Zijinshan ore area are similar, and they have the potential of prospecting for the “Zijinshan type” copper-gold deposit.