埃塞俄比亚西部地区奥格哈利法金矿成矿规律与找矿标志

西埃塞俄比亚地盾位于阿拉伯-努比亚地盾增生岛弧的北东向缝合带内,属于埃塞俄比亚西部地区造山带型金矿远景区。奥格哈利法金矿为西埃塞俄比亚地盾的典型矿床之一,通过分析该矿床的地质特征和控矿因素,总结成矿规律和找矿标识,有助于该区域矿床的勘查活动。奥格哈利法金矿产于与泛非期造山活动有关的剪切带中,金矿的成矿物质来源于前寒武基底,通过造山期的变质作用活化、运移至张性构造中富集成矿。矿体严格受构造控制,围岩蚀变包括钠长石化、硅化、黄铁矿化和绿帘石化,其中硅化和黄铁矿化与金矿化关系密切。该区域找矿可考虑综合运用土壤地球化学测量方法进行靶区的圈定和筛选,硅化和黄铁矿化蚀变为直接找矿标志。

Metallogenic regularity and prospecting indicator of gold deposit in Horkhalifa, western Ethiopia

The West Ethiopian Shield is located in the north-east suture zone of the Arab-Nubian Shield Accretionary Arc, which belongs to the orogenic gold deposits prospective area in the western part of Ethiopia. The Horkhalifa Gold Mine is one of the typical deposits of the Western Ethiopian Shield. By analyzing the geological characteristics and mineralization-controlling factors of the deposit, summarizing the metallogenic rules and prospecting signs, it is helpful to the exploration activities of the deposits in this area. The Horkhalifa gold deposit is produced in the shear zone related to Pan-African orogenic activities. The source of ore-forming material of the gold deposit originates from the Precambrian basement, which is activated and migrated to the extensional structure through the metamorphism of the orogenic period. The ore body is strictly controlled by structure. Wall rock alteration includes albiteization, silicification, pyritization and epidotization, among which silicification and pyritization are closely related to gold mineralization. Prospecting in this area can consider comprehensively using soil geochemical measurement methods to delineate the target area, and silicification and pyritization are direct geological signs.