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黔西北铅锌成矿区是川滇黔铅锌成矿省的重要组成部分,已发现中—小型矿床(点)100余处,它们的分布严格受到区域性构造的控制。在系统收集前人资料的基础上,对黔西北铅锌矿床成矿流体中的金属来源进行了深入的探讨。矿石的206Pb/204Pb为18.439~18.729(均值18.563,n=25),207Pb/204Pb为15.681~15.887(均值15.748,n=25)和208Pb/204Pb为38.885~39.522(均值39.112,n=25);黄铁矿的206Pb/204Pb为18.280~18.768(均值18.571,n=10),207Pb/204Pb为15.677~15.920(均值15.737,n=10)和208Pb/204Pb为38.609~39.144(均值38.940,n=10);闪锌矿的206Pb/204Pb为18.029~18.726(均值18.448,n=34),207Pb/204Pb为15.505~15.825(均值15.689,n=34)和208Pb/204Pb为38.145~39.455(均值38.772,n=34);方铅矿的206Pb/204Pb为18.062~19.900(均值18.536,n=83),207Pb/204Pb为15.440~16.334(均值15.717,n=83)和208Pb/204Pb为38.004~40.695(均值39.022,n=83)。矿石全岩与硫化物单矿物具有相似的Pb同位素组成,表明脉石矿物对矿石全岩没有明显的Pb同位素影响,矿石全岩和金属硫化物Pb同位素所指示的物源信息均能反映成矿流体中金属的来源。经与地壳、地幔和造山带及峨眉山玄武岩、赋矿沉积岩和基底岩石Pb同位素组成特征对比,发现黔西北铅锌矿床成矿流体中的金属具有混合来源特征,主要来自赋矿地层沉积岩和基底岩石。综合分析认为,黔西北铅锌矿床成矿流体中的金属是由循环的盆地卤水活化、淋滤流经地层(包括基底和赋矿地层)岩石所得。
The lead-zinc metallogenic area in northwestern Guizhou is an important part of the lead-zinc mineralization province in Sichuan, Yunnan and Guizhou. More than 100 medium- and small-sized deposits (spots) have been found, and their distribution is strictly controlled by the regional structure. Based on the systematic collection of previous data, the metal sources in the ore-forming fluids of the lead-zinc deposits in northwest Guizhou Province are discussed in depth. The ore 206Pb / 204Pb ranged from 18.439 to 18.729 (mean 18.563, n = 25), 207Pb / 204Pb ranged from 15.681 to 15.887 (mean 15.748, n = 25) and 208Pb / 204Pb ranged from 38.885 to 39.522 (mean 39.112, n = 25) The 206Pb / 204Pb ranged from 18.280 to 18.768 (mean 18.571, n = 10) for pyrite and from 15.677 to 15.920 for 207Pb / 204Pb (mean 15.737, n = 10) and 38.609 to 39.144 for 208Pb / 204Pb (mean 38.940, n = 10 ); Sphalerite 206Pb / 204Pb 18.029-18.726 (mean 18.448, n = 34) 207Pb / 204Pb 15.505-15.825 (mean 15.689 n = 34) and 208Pb / 204Pb 38.145-39.455 (mean 38.772, n = 34); the 206Pb / 204Pb for galena ranged from 18.062 to 19.900 (mean 18.536, n = 83), 207Pb / 204Pb ranged from 15.440 to 16.334 (mean 15.717, n = 83) and 208Pb / 204Pb ranged from 38.004 to 40.695 , n = 83). All rock and sulfide single minerals have similar Pb isotopic compositions, indicating that gangue minerals have no obvious Pb isotopic effect on the whole rock. The source information indicated by the ore ores and Pb isotopes of metal sulfides can all reflect mineralization The source of the metal in the fluid. Comparing with the Pb isotopic compositions of the crust, mantle and orogen, and the Emeishan basalts, ore-hosting sediments and basement rocks, it is found that the metals in the ore-forming fluid of the northwestern Guizhou province have the characteristics of mixed sources, mainly from the sedimentary rocks and basement rocks . According to a comprehensive analysis, the metal in the ore-forming fluids of the lead-zinc deposits in northwestern Guizhou is activated by recycled basinal brine and leached through rocks in the strata, including basement and ore-hosting strata.