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纳雍枝铅锌矿床位于扬子陆块西南缘的黔西北铅锌成矿区东南部五指山背斜南东翼,矿体产于寒武系下统清虚洞组白云岩中。矿区主要有2层铅锌矿体,为层状、似层状,产状与围岩一致,矿石类型主要有浸染状铅锌矿石、脉状铅锌矿石、条带状铅锌矿石,属沉积改造型铅锌矿床。矿石硫化物的δ34S值变化于18.0‰~23.8‰,成矿流体的总硫同位素值(δ34SΣS)大于+19.7‰,富34S,具典型壳源特征,与海水硫酸盐的硫同位素组成范围接近,可能主要来自容矿地层寒武系及其下伏地层震旦系海相硫酸盐岩的热化学还原;206Pb/204Pb为17.849~17.973,207Pb/204Pb为15.640~15.733,208Pb/204Pb为37.932~38.246,主要分布于上地壳演化线上方,部分位于造山带和上地壳铅演化线范围内,μ值9.61~9.79,Th/U比值3.81~3.89,指示铅来源于上地壳,铅同位素组成与上震旦统灯影组碳酸盐岩相近,矿石铅的单阶段模式年龄为591 Ma~636 Ma,与上震旦统灯影组沉积时代一致,推测矿床成矿物质可能来自矿层下伏地层上震旦统灯影组。
The Nayongzian lead-zinc deposit is located in the south east wing of the Wuzhishan anticline in the southeast of the Qianxinan Pb-Zn metallogenic region in the southwestern margin of the Yangtze block. The ore body is found in the dolomite of the Lower Paleogene Qingxudong Formation in the Cambrian. The mining area is mainly composed of 2 layers of lead-zinc ore bodies, which are stratified and lamellar. The occurrences are consistent with the surrounding rock. The ore types include mainly lead-zinc ore, vein lead-zinc ore and banded lead-zinc ore, Modified lead-zinc deposits. The δ34S value of ore sulfide varies from 18.0 ‰ to 23.8 ‰, and the total sulfur isotope value (δ34SΣS) of ore-forming fluid is greater than + 19.7 ‰, and rich in 34S with typical crustal characteristics, which is close to the range of sulfur isotope composition of seawater sulphate. Probably from the thermochemical reduction of the Cambrian and its underlying stratigraphic Sinian marine sulfate rock in the ore-hosting stratum. The values of 206Pb / 204Pb ranged from 17.849 to 17.973, with 207Pb / 204Pb ranging from 15.640 to 15.733 and from 208Pb / 204Pb ranging from 37.932 to 38.246 , Mainly distributed above the upper crustal evolution line and partly within the range of the orogenic belt and upper crustal lead evolution line, with μ values ranging from 9.61 to 9.79 and Th / U ratios ranging from 3.81 to 3.89, indicating that lead is derived from the upper crust, lead isotopic composition and upwelling The Dengying shadow formation is similar to carbonate rocks. The single-phase model age of lead ore is 591 Ma ~ 636 Ma, consistent with the sedimentary age of the Upper Sinian Dengying Formation. It is speculated that ore-forming materials may originate from the Upper Sinian Lights group.