坦桑尼亚环维多利亚湖地区金矿勘查地球物理方法应用研究

Study on application of geophysics method for gold mine prospecting in around Lake Victoria region,Tanzania

坦桑尼亚环维多利亚湖地区绿岩带是东非重要的太古宙金成矿带,由于受到准平原化作用的影响,总体覆盖较厚、较广,常规的地质填图和找矿方法效果不佳,地球物理勘查方法在金矿资源勘查中发挥了至关重要作用,为大型隐伏铁建造(BIF)型姆瓦莫拉金矿和中型构造蚀变岩型尼亚斯罗利金矿的发现起到了关键性的指导作用;以环维多利亚湖地区金矿床的成矿地质条件、岩石物理性质、地球物理场特征等信息为基础,以姆瓦莫拉金矿和尼亚斯罗利金矿为典型案例,系统总结了坦桑尼亚金矿床有效的地球物理勘查技术方法,首次归纳建立了该国境内铁建造型金矿、构造蚀变岩型金矿的地球物理找矿模型,并提出了物探勘查这两种类型金矿床可采取的最佳方法组合模式,对进入坦桑尼亚的世界各国地勘部门寻找金矿具有一定的借鉴作用和参考意义.随着我国对海外矿产勘查热度的增大,坦桑尼亚金矿床地球物理勘探方法和工作模式对世界上其他国家或地区绿岩带型金矿勘查、评价及找矿方向也具有重要指导意义.

The greenstone belt around Lake Victoria region in Tanzania is an important archean gold metallogenic belt in east Africa. Due to the influence of quasi-plainization, the overall coverage is thicker and wider, Conventional geological and mineral mapping methods are powerless, Geophysical survey method plays a crucial role in the exploration of gold resources, and played a key guiding role in the discovery of the large-scale hidden iron formation(BIF) type gold deposit for Mwamola and the medium-scale tectonic altered rock type gold deposit for Nyasirori. Based on the information of the ore-forming geological conditions, petrophysical properties, and geophysical field characteristics of the gold deposits around the Lake Victoria region, and taking the Mwamola and Nyasirori gold mines as typical cases, a systematic summary of effective geophysical prospecting technical methods for gold deposits in Tanzania, have for the first time summarized and established geophysical prospecting models for iron formation(BIF) type gold deposits and tectonic altered rock type gold deposits in the country, and put forward the two types of gold deposits that can be taken in the best combination model of geophysical prospecting methods. It has certain reference function and reference significance for geological prospecting departments of countries around the world who enter Tanzania to find gold mines. As China ’s increasing interest in overseas mineral exploration, the geophysical exploration methods and working models of Tanzania’s gold deposits have also played an important role in guiding the exploration, evaluation, and prospecting of greenstone belt type gold deposits in other countries or regions around the world.