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冷水坑Ag-Pb-Zn矿田发育2类矿体,即花岗斑岩体内大脉状、细脉浸染状矿体和火山旋回内层状矿体,引起众多学者重视。但与大脉状、细脉浸染状矿体有关的花岗斑岩与层状矿体的关系、层状矿体赋矿层铁锰碳酸岩层成因背景、2类矿体间金属硫化物的成分差异等问题尚未引起足够关注。本文选取冷水坑矿田内金属储量最大的下鲍矿床,对一条横穿花岗斑岩及层状矿体的剖面进行了重点考察研究,对其元素含量及比值的变化特征进行深入讨论,进而对2类矿体内闪锌矿矿物化学进行了对比研究。花岗斑岩及层状矿体野外接触关系清晰,未出现渐变特征。二者元素含量及比值差异明显,花岗斑岩具有更高的Al、Ba、Sr、K、Na含量,铁锰碳酸盐岩层则具更高Ag、Fe、Mn、Zn、Pb、Mg含量。铁锰碳酸盐岩层元素化学特征表明其沉积成因,并未经历规模较大的热液交代作用,形成背景为火山-沉积有关的陆相深湖盆。对大脉矿体及层状矿体内发育的闪锌矿进行了电子探针分析,闪锌矿总体w(S)32.05%~33.81%,平均33.02%;w(Zn)53.51%~63.79%,平均59.38%;w(Fe)变化范围较大(2.02%~12.42%),2种矿体间差异显著,层状矿体中闪锌矿w(Fe)含量2.02%~7.69%,平均4.17%,大脉状矿体闪锌矿w(Fe)8.02%~12.42%,平均9.49%。层状矿体赋存于铁锰碳酸岩层内,但矿体内闪锌矿Fe、Mn含量却低于大脉状矿体中的闪锌矿。综合分析认为,2种矿体的Fe、Mn、Pb、Zn元素在成矿相关岩浆体系内,可能经历了不同物理化学条件(流体成分、温度、压力、p H值等)的影响,造成成矿相关岩浆体系的差异。
There are two types of orebodies in the cold puddle Ag-Pb-Zn orefield, that is, the veins of the granite porphyry and the disseminated inner layered ore bodies of volcanic veins have aroused many scholars’ attention. However, the relationship between the granite porphyry and the layered orebodies related to the veins and disseminated disseminated orebodies, the origin of the Fe-Mn carbonate rocks deposited by the layered orebodies, the compositional differences of the intermetallic sulfides between the two types of orebodies And other issues have not attracted enough attention. In this paper, we choose the lower Baobao ore deposit with the largest metal reserves in Lengshukeng orefield, and focus on the investigation of a section crossing the granite porphyry and stratiform ore body. The changes of its element content and ratio are discussed in detail. The mineral chemistry of sphalerite in two types of ore bodies is compared. Granite porphyry and layered ore contact in the wild clear, there is no gradual change. The content and ratio of the two elements are obviously different. The granite porphyry has a higher content of Al, Ba, Sr, K and Na, while the Fe-Mn carbonate layer has a higher content of Ag, Fe, Mn, Zn, Pb and Mg . The elemental chemical characteristics of the Fe-Mn carbonate rocks indicate their sedimentary origin without experiencing large-scale hydrothermal metasomatism and the formation of a deep volcanic-sedimentary continental lake basin. Electron microprobe analysis of sphalerite developed in vein vein and bedded ore body showed that sphalerite overall ranged from 32.05% to 33.81% with an average of 33.02%, w (Zn) ranging from 53.51% to 63.79% With an average of 59.38%. The range of w (Fe) was large (2.02% ~ 12.42%), and there was significant difference between the two ore bodies. The wurtzite content in layered ore bodies was 2.02% ~ 7.69% , Large vein mineral sphalerite w (Fe) 8.02% ~ 12.42%, an average of 9.49%. Layered orebodies occur in the Fe-Mn carbonate rocks, but the content of sphalerite Fe and Mn in the ore body is lower than that of the sphalerite in the vein-type ore bodies. According to the comprehensive analysis, the Fe, Mn, Pb and Zn elements of the two ore bodies may have undergone different physicochemical conditions (fluid composition, temperature, pressure and p H values) in the ore-forming magmatic system, Differences of ore-related magmatic systems.