内蒙古拜仁达坝西矿区锌多金属矿床原生地球化学异常模式

摘要

拜仁达坝西矿区锌多金属矿床为典型的热液脉型多金属矿床。通过对矿区内岩石中元素富集贫化规律、原生异常分带序列、地球化学参数垂向变化、硫与铁及成矿元素的协同平衡关系等的研究，发现矿床中发育成矿及伴生元素正异常和贫化元素Ba、Sr、Na2 O的负异常，矿床整体产于贫化元素形成的亏损晕中；矿床直接指示元素为Zn、Ag、Pb、Cu、Cd、Sb、Hg，间接指示元素为Ba、Sr、Na、As、W、Rb；矿床原生异常轴向分带序列为Ag-Hg-Pb-As-Cd-Zn-Bi-Au-Cu-Sb-Na2 O-Sr-Ba-W-Co-Mo-Rb，出现As、Sb等元素“反分带”现象；元素含量及地球化学参数垂向变化波动较大，反映叠加成矿作用强烈，成矿过程复杂；各类异常特征均显示成矿地球化学系统在矿床深部尚未终止，推测已知矿床深部可能存在隐伏盲矿体。初步构建了矿床原生地球化学异常模式，为矿区深部及外围找矿工作提供了依据。%The West Bairendaba zinc polymetallic deposit in the middle and eastern part of Inner Mongolia is a typical hydrothermal vein-type polymetallic deposit. In this paper, element enrichment and depletion regularity, primary anomaly zoning sequence, vertical variation of geochemical parameters and the relationship between sulfur, iron and ore-forming elements in the rock samples of the de-posit were studied. The results show that there exist positive anomalies of ore-forming and associated elements and negative anomalies of Ba, Sr and Na2 O in the ore deposit which as a whole occurs in a depletion halo formed by the negative anomalies. The major indicator elements of the deposit include Zn, Ag, Pb, Cu, Cd, Sb and Hg, and the indirect indicator elements are Ba, Sr, Na, As, W and Rb. The axial zoning sequence of the primary anomaly in the ore deposit is Ag-Hg-Pb-As-Cd-Zn-Bi-Au-Cu-Sb-Na2 O-Sr-Ba-W-Co-Mo-Rb, with the existence of the anti-zoning phenomenon of As and Sb. The high element content and vertical fluctuations of geochemical pa-rameters show that the mineralization experienced a superimposition and complex process. The authors established an primary geochemi-cal pattern for the ore deposit. As various types of anomalies indicate that the ore-forming geochemical system has not yet terminated in the depth, the authors infer that there possibly exist concealed blind ore bodies in the depth. The result obtained by the authors provides a basis for the prospecting work in the depth and the periphery of the ore district.