青海下柳沟铜铅锌矿床地质特征与硫化物电子探针分析

Geological Characteristics and Electron Probe Analysis of Sulfides in the Xialiugou Cu-Pb-Zn Deposit of Qinghai Province

青海祁连下柳沟铜铅锌矿床位于北祁连走廊南山南坡一带,是北祁连地区较为重要的块状硫化物矿床。矿体赋存于中寒武统黑茨沟组酸性火山岩中,受NW向断裂构造和地层控制,产状随地层变化而变化。本次研究从矿床地质特征研究入手,再对区内不同阶段的硫化物进行电子探针分析,探讨金属硫化物的地球化学特征、矿床成矿环境,从而对本区下步找矿工作提供依据。通过研究可知,下柳沟地区矿体形态复杂,矿体沿走向、倾向品位及厚度变化均较大,主要呈似层状、条带状、网脉状、透镜状等产出,矿石组合以铜铅锌矿石和铅锌矿石为主。通过对闪锌矿中Zn、S、Cd、Fe、S、Co、Ni等元素含量的分析,表明本区矿床为火山喷气沉积型块状硫化物矿床。通过黝铜矿电子探针分析可知,本区目前揭露的仅为矿体的中上部,深部可能还存在隐伏矿体。

Located in the southern slope of Nanshan Mountains in North Qilian Corridor,the Xialiugou Cu-Pb-Zn deposit is a major massive sulfide deposit. Its ore bodies are present in the acid volcanic rocks of the Middle Cambrian Heicigou Formation,controlled by NW-trending faults and formation. Their occurrence changes with the strata. This work studies the geological characteristics of this deposit,makes electron probe analysis of sulfides for different stages in the area,and discusses the geochemical characteristics and metallogenic environment of metallic sulfide,so as to provide basis for the next step of prospecting in this area. The results show that the ore bodies in the Xialiugou area are complex in shape. The grade and thickness of the ore bodies change significantly along the direction and inclination. The ore bodies look like quasi-layering,banded,reticulated,and lenticular. The ore combination is dominated by copper-lead-zinc ores and lead-zinc ores. Analysis of the content of Zn,S,Cd,Fe,S,Co,Ni and other elements in sphalerite shows that this deposit is a massive sulfide deposit attributed to the volcanic exhalative type. The electron probe analysis of tetrahedrite indicates that only the middle and upper parts of the deposit are exposed at present,and its hidden lower part may exist in the deep subsurface.