辽宁五龙金矿床硫、铅同位素组成及深部三维地质模型

    Sulfur and lead isotopic compositions and deep 3D geological model of the Wulong gold deposit in Liaoning Province

    • 摘要: 辽宁五龙金矿是辽吉裂谷内典型的大型金矿床,成矿作用复杂. 为了深入揭示其成矿物质来源及深部特征,对五龙金矿开展了S、Pb以及重、磁、电剖面研究. 金矿石δ34S值为0.1‰~3.5‰ (平均为1.66‰),五龙岩体δ34S值为-21.4‰~-8.4‰ (平均为-17.05‰). 金矿石206Pb/204Pb为17.569~17.672, 207Pb/204Pb为15.572~15.681, 208Pb/204Pb为38.533~38.904;三股流岩体206Pb/204Pb为17.649~17.945, 207Pb/204Pb为15.552~15.616, 208Pb/204Pb为38.521~38.934;五龙岩体206Pb/204Pb为17.422~17.769, 207Pb/204Pb为15.591~15.634, 208Pb/204Pb为38.323~38.845. S同位素显示,金矿石硫源为岩浆硫,五龙岩体的S同位素可能有地层硫的混入. Pb同位素显示,三股流岩体和金矿石Pb同位素组成有相似性,五龙岩体和金矿石Pb同位素组成有差异. 五龙金矿为岩浆热液型矿床,与早白垩世岩浆活动密切相关. 重、磁、电剖面及三维地质模型显示,五龙金矿东北部深部存在隐伏早白垩世岩体,其深部具有找矿潜力.

       

      Abstract: The Wulong gold deposit in Liaoning is a typical large-scale gold deposit within the Liao-Ji Rift, with complex mineralization processes. To further investigate its ore-forming material sources and deep-seated characteristics, studies on S and Pb isotopes, as well as gravity, magnetic, and electrical profiles, were conducted on the gold deposit. The δ34S values of the gold ores range from 0.1‰ to 3.5‰ (averaging 1.66‰), whereas those of the Wulong pluton range from -21.4‰ to -8.4‰ (averaging -17.05‰). In terms of lead isotopes, the gold ores yield 206Pb/204Pb ratios of 17.569-17.672, 207Pb/204Pb ratios of 15.572-15.681, and 208Pb/204Pb ratios of 38.533-38.904. The Sanguliu pluton exhibits similar compositions, with 206Pb/204Pb ratios of 17.649-17.945, 207Pb/204Pb ratios of 15.552-15.616, and 208Pb/204Pb ratios of 38.521-38.934. In contrast, the Wulong pluton shows relatively lower radiogenic lead isotopic compositions, with 206Pb/204Pb ratios of 17.422-17.769, 207Pb/204Pb ratios of 15.591-15.634, and 208Pb/204Pb ratios of 38.323-38.845. Sulfur isotopic data indicate that the sulfur in the gold ores is of magmatic origin, whereas the sulfur isotopic composition of the Wulong pluton likely reflects the incorporation of crustal sulfur. Lead isotopic data reveal a similarity in lead isotopic compositions between the Sanguliu pluton and the gold ores, but a distinct difference between Wulong pluton and the gold ores. The Wulong gold deposit is classified as a magmatic-hydrothermal deposit and is closely associated with Early Cretaceous magmatism. Gravity, magnetic, and electrical profiles, combined with a 3D geological model, reveal a concealed Early Cretaceous pluton in deep on the northeast of Wulong gold deposit, indicating significant deep-seated prospecting potential.

       

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