地球物理学进展 ›› 2019, Vol. 34 ›› Issue (6): 2361-2368.doi: 10.6038/pg2019CC0483

• 应用地球物理学Ⅰ(油气及金属矿产地球物理勘探) • 上一篇    下一篇

坦桑尼亚凯巴卡瑞地区构造蚀变岩型金矿航磁异常特征与找矿意义

袁杨森, 李水平*, 程华, 卫建征, 刘正好, 曹杰, 邵江波, 赵华奇   

  1. 河南省地质矿产勘查开发局第二地质矿产调查院,郑州 450001
  • 收稿日期:2019-03-12 修回日期:2019-08-11 出版日期:2019-12-20 发布日期:2019-12-29
  • 作者简介:袁杨森,男,1982年生,四川阆中市人,硕士,高级工程师,长期从事境外固体矿产勘查和研究工作.(E-mail:76738371@qq.com)
  • 基金资助:
    国外矿产资源风险勘查专项资金项目(201210B01600234)资助.

Aeromagnetic anomaly of the tectonic rock type gold deposit in Kiabakari area, Tanzania and its prospecting significance

YUAN Yang-sen, LI Shui-ping*, CHENG Hua, WEI Jian-zheng, LIU Zheng-hao, CAO Jie, SHAO Jiang-bo, ZHAO Hua-qi   

  1. No.2 Institute of Geological and Mineral Resources Survey of Henan, Zhengzhou 450001, China
  • Received:2019-03-12 Revised:2019-08-11 Online:2019-12-20 Published:2019-12-29

摘要: 坦桑尼亚是东非第一产金大国,构造蚀变岩型金矿是该国的一个重要金矿床类型,该类型金矿床与断裂构造中的构造蚀变带密切相关,主要分布在坦桑尼亚环维多利亚湖东部、西南部及东南部绿岩带中;凯巴卡瑞地区内岩石磁性表现为强-中-弱-微或无的强度等级,岩石相互之间磁性差异明显,其航磁异常显示的地质信息比较详尽,反映的磁性地层、岩体界线清晰,线性构造特征明显.依据坦桑尼亚凯巴卡瑞地区尼亚斯罗利金矿床上的航磁异常表现形式,对凯巴卡瑞地区航磁异常强度、规模、形态及延伸等特征进行了认真分析和对比研判,认为该区域航磁异常客观地反映了与构造蚀变岩型金矿有关联的断裂构造和绿岩分布区,构造蚀变带、金矿脉以及所赋存的绿岩地层在航磁异常上表现为低强度磁异常,其他岩石(条带状铁建造、辉绿岩、花岗岩)在航磁异常上表现为高强度磁异常,据此选择的找矿靶区通过地面物探方法(高精度磁测、微磁测量)查证,取得了明显的找矿效果;凯巴卡瑞地区航磁异常解译厘定的地质信息,为进一步预测成矿区域、圈定找矿靶区及间接发现构造蚀变岩型金矿床奠定了基础,因而预判坦桑尼亚凯巴卡瑞地区分布的航磁异常具有寻找构造蚀变岩型金矿的较大潜力.

关键词: 坦桑尼亚, 穆索马-马拉绿岩带, 航磁异常, 构造蚀变岩型金矿床

Abstract: Tanzania is the largest gold producer in East Africa,tectonic rock type gold deposit is an important gold deposit type in Tanzania. This type of gold deposit is closely related to the tectonic alteration zone in the fault structure, and is mainly distributed in the greenstone belt in the eastern, southwestern and southeastern parts of Lake Victoria in Tanzania. The rock magnetism in the Kiabakari area is characterized by strong-medium-weak-micro-or non-strength grades. The rocks have obvious magnetic differences with each other. The geological information displayed by the aeromagnetic anomalies is more detailed, and the magnetic strata and rock mass boundaries reflected are clear. Linear structural features are obvious. According to the characteristics of aeromagnetic anomaly of the Nyasirori gold mine, in Kiabakari area, Tanzania, the characteristics of aeromagnetic anomaly intensity, scale, shape and extension in Kaibaqiarui region were analyzed and compared. It was concluded that the aeromagnetic anomalies in the region objectively reflected the fracture structures and greenstone distribution areas associated with tectonic altered rock gold deposits. The tectonic erosion belts, gold veins, and the existing greenstone formations are characterized by low intensity magnetic anomalies, and other rocks(banded iron formations, pyroxenite, granite) are characterized by high intensity magnetic anomalies. According to this, the target area selected by the ground Geophysical method(high-precision magnetic measurement, micromagnetic measurement) was verified and the obvious prospecting effect was obtained, The geological information determined by the interpretation of aeromagnetic anomalies in the Kiabakari area laid the foundation for further prediction of metallogenic areas, locate the target area, and indirect discovery of structural altered rock gold deposits. Therefore, the prediction of the distribution of aeromagnetic anomalies in the Kiabakari region of Tanzania has great potential for searching for tectonic altered rock gold deposits.

Key words: Tanzania, Musoma-Mara greenstone belt, Aeromagnetic anomaly, Tectonic rock type gold deposit

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