张家口梁家沟—火石沟铅锌银多金属矿区找矿潜力分析

An analysis of the prospecting potential of Pb-Zn-Ag polymetallic deposits in the Liangjiagou-Huoshigou ore district of Zhangjiakou area

张家口南部燕山台褶带内中—新元古代碳酸盐岩地层分布广泛,岩性以白云岩为主。该时代地层中分布有梁家沟、银洞沟、常庄子等铅锌银多金属矿床(点)分布。文章以赤城县梁家沟-火石沟铅锌银多金属矿区为例,采用统计法和局部奇异性两种方法圈定了成矿元素1∶20万水系沉积物异常,结果显示化探元素异常区内包含3条断裂,根据矿床为后生成因推测异常区成矿潜力较大。在此基础上,结合控矿因素对找矿靶区范围进行了1∶5万水系沉积物加密采样,共圈出3处异常。通过对比分析,已知矿体与较弱的3号异常相吻合,而异常面积较大、强度较高的1、2号化探异常目前无工业矿体发现,应为今后找矿的重点区域。野外对1、2号异常区进行了基岩原生晕地球化学剖面测量,显示在异常中心区域白云岩中成矿元素铅锌银含量高,进一步佐证了上述异常区域的找矿潜力。

Carbonate rocks of Meso- Proterozoic and Neo- Proterozoic period are widely distributed along Yanshan fold belt insouthern Zhangjiakou and are composed mainly of dolomite. Some polymetallic mineral deposits（ore spots）, such as Laing Jiagou,Yingdonggou and Changzhuangzi, are distributed in strata. With the Liangjiagou deposit as a study object, the authors used statistical method and local singularity means to analyze the data of stream sediments（1∶200000） so as to delineate geochemical anomalies. The results show that the areas of geochemical anomalies include three major faults, where there is great potential in search for polymetallic orebodies according to the epigenetic genesis of the ore deposits. The authors adopted densed sampling in important potential areas and delineated three geochemical anomalies. A comprehensive analysis shows that No. 3 anomaly is relatively weak and is consistent with the orebody. No. 1 and No. 2 anomalies not only have high intensity but also possess fairly large areas. The primary halos of bedrock profile survey show that the content of Pb, Zn and Ag in dolomite is significantly higher that in the center of the anomaly area, and this provides further evidence for the prospecting potential of the anomaly area.