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川滇黔铅锌成矿域位于扬子克拉通的西南缘,是我国十分重要的铅锌成矿区带之一,相关成矿物质来源认识长期存在较大争议。本文以该区研究程度较低的黔西北云炉河坝矿集区为研究对象,对矿集区内典型的铅锌矿床(包括,昊星、富强、顺达和狮子洞等)进行了硫、铅同位素研究,以探讨其成矿物质的来源。硫同位素分析结果表明,昊星矿区硫化物的δ34S值变化范围很小(-1.5‰~2.7‰),且集中于零值附近,暗示矿区硫可能主要来自于幔源岩浆硫的贡献,另外还发现一件黄铁矿样品具有较低的δ34S值(-18.1‰),反映矿区可能还存在细菌还原硫的贡献。铅同位素数据表明,不同矿区不同类型矿石的Pb同位素组成十分均一,206Pb/204Pb介于18.196~18.525,207Pb/204Pb为15.645~15.731,208Pb/204Pb为38.415~39.058,且不同样品之间的Pb同位素不存在明显差别,表明云炉河坝矿集区中的众多铅锌矿床(点)可能具有统一的铅金属来源,且后期的氧化淋滤作用并未导致明显的铅同位素分馏。通过与区域上不同时代地层以及邻区铅锌矿床综合对比,我们初步认为矿区铅可能主要源于该区基底岩石,而非其赋矿地层和二叠纪玄武岩。
Lead-zinc mineralization in Sichuan, Yunnan and Guizhou is located in the southwestern margin of Yangtze craton, which is one of the most important lead-zinc metallogenic belts in China. There is a long-standing controversy about the source of ore-forming materials. In this paper, the less concentrated study area of Qianlu Heba mine in the northwestern part of Guizhou is taken as the research object, and the sulfur-bearing typical lead-zinc deposits (including Haoxing, Fuqiang, Shunda and Shizidong) , Lead isotope studies to explore the source of its metallogenic material. The results of sulfur isotope analysis show that δ34S value of sulfide in Haoxing mining area is small (-1.5 ‰ ~ 2.7 ‰) and concentrated in the vicinity of zero value, suggesting that the sulfur in the ore area probably comes from the contribution of mantle magma sulfur, A pyrite sample was found to have a low δ34S value (-18.1 ‰), reflecting the possible contribution of bacteria to reduced sulfur in the mining area. Pb isotopic data show that the Pb isotopic composition of different types of ores in different mining areas is very homogeneous with 206Pb / 204Pb between 18.196 and 18.525, 207Pb / 204Pb between 15.645 and 15.731 and between 208Pb and 204Pb between 38.415 and 39.058, and Pb isotope between different samples There is no obvious difference, indicating that many lead-zinc deposits (spots) in the central area of Yunhe Heba ore deposit may have a uniform source of lead metal, and the subsequent oxidative leaching does not lead to obvious lead isotope fractionation. Based on the comprehensive comparison of different age strata and lead-zinc deposits in the area, we initially believe that lead in the mining area may be mainly derived from the basement rocks in this area rather than the ore-bearing strata and Permian basalts.