滇东北会泽麒麟厂铅锌矿床矿化-蚀变指数定量分析及深部找矿意义

    Quantitative analysis of mineralization-alteration index and deep prospecting significance of Qilinchang Pb-Zn deposit in Huize, northeastern Yunnan

    • 摘要: 会泽超大型铅锌矿是滇东北铅锌多金属矿集区最具代表性的矿床之一。为了有效地提取和区分不同矿化-蚀变分带内铅锌矿化、黄铁矿化、白云石化等矿化-蚀变信息, 以麒麟厂1249 m中段典型剖面为例, 应用大比例尺蚀变岩相学填图方法, 基于矿化-蚀变岩的热液蚀变指数与迁入元素增长指数的定量分析, 对比和剖析了矿化蚀变类型与各矿化-蚀变带的岩石组成、结构构造等特征。结果表明, 该矿床主要的蚀变类型为白云石化、方解石化和黄铁矿化, 主要矿化为闪锌矿化、方铅矿化。以矿体为中心, 从矿体下盘围岩→矿体→矿体上盘围岩, 矿化-蚀变分带呈现出远矿浅灰色粗晶白云岩带(Ⅰ)→针孔状白云岩带(Ⅱ)→米黄色粗晶白云岩带(Ⅲ)→近矿灰白色粗晶白云岩带(Ⅳ)→铅锌矿化带(Ⅴ)→近矿灰白色粗晶白云岩带(Ⅳ)的变化规律。TFe、CaO、MgO、Pb、Zn在不同的矿化蚀变分带内均保持迁入富集状态, 其中TFe、Pb和Zn迁入富集明显; 矿化-蚀变指数值和迁入元素增长指数与矿化蚀变分带在空间上具有一致性, Ⅴ带呈现的矿化蚀变指数值(AIAITFeAIPb+Zn)最高, 而AIMgo值最低, 明显区别于其他蚀变带; 从Ⅰ带至Ⅴ带, 迁入元素增长指数(ZZnZPbZTFe)总体呈增长趋势, 且Ⅴ带的ZTFeZPbZZn值明显高于围岩。矿化蚀变指数研究揭示了热液蚀变作用与成矿的关系, 亦证实了空间上矿化蚀变分带的规律性, 对于同类矿床深部勘探具有指导意义。

       

      Abstract: The giant Huize Pb-Zn deposit is the most representative deposit of Pb-Zn polymetallic ore concentration area in northeastern Yunnan.In order to effectively extract and distinguish the mineralization-alteration information such as lead-zinc mineralization, pyritization and dolomitization in different mineralization-alteration zones, using large scale alteration petrographical mapping method, taking the typical levels of 1249 m as an example, to analyze the levels' mineralization-alteration types, altered rock composition, structure and other characteristics base on quantitative analysis of hydrothermal alteration index and growth index of element transfer-in.The results show that the main alteration types are dolomitization, calcitization and pyritization.Mineralization mainly are sphalerite and galena.Taking the ore body as the center, from footwall rock of ore body to ore body to hanging wall rock of ore body, the mineralization-alteration zoning shows that grayish white coarse-grained crystalline dolomite which is far from the orebody(Ⅰ), coarse-grained dolomite with pinholes(Ⅱ), beige coarse-grained crystalline dolomite(Ⅲ), grayish white coarse-grained crystalline dolomite which is closed to the orebody(Ⅳ), orebody(Ⅴ)and grayish white coarse-grained crystalline dolomite which is closed to the orebody(Ⅳ).The element TFe, CaO, MgO, Pb, and Zn in the different mineralization alteration zones almost keep transfer-in.Among them, the element TFe, Pb and Zn are the most obvious.Moreover, the quantitative calculation results of the mineralized alteration rocks' mineralization alteration index and the growth index of the elements transfer-in are consistent with the mineralization alteration zone in space.The values of alteration index(AI), TFe's alteration index(AITFe), and(Pb+Zn)'s alteration index(AIPb+Zn)are the highest in the Ⅴ zone while the value of MgO's alteration index(AIMgO)is the lowest, clearly distinguished from other alteration zones; The values of Zn, Pb and TFe's growth index of element transfer-in(ZZn, ZPb and ZTFe)are generally increasing from Ⅰ zone to Ⅴ zone, and the values of ZZn, ZPb and ZTFe are significantly higher than those in surrounding rock.The study of mineralization alteration index reveals the relationship between hydrothermal alteration and mineralization, and also proves the rationality of spatial mineralization alteration zoning, which has guiding significance for deep exploration of similar deposits.

       

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