坦桑尼亚 Maheiga 金矿区航空、地面磁力异常特征与找矿研究

摘要

与条带状含铁建造（BIF）伴生的金矿产量约占世界黄金总产量的13%，而坦桑尼亚近1/3的黄金产量来自于 BIF 型金矿。通过对坦桑尼亚环维多利亚湖南部某区域航空磁力异常特征分析，结合研究区地质背景，解译了与金矿有关的 BIF 序列赋存范围，进而划定为地面找矿靶区；该区内沼泽性黑土和风化层覆盖较厚，利用赋矿岩石与围岩磁性差异显著的特点，地面磁测圈定了与金矿有关条带状含铁建造的分布位置；其磁测成果反映的ΔT 异常清晰、形态规整且可信度高，为钻探工程布置提供了强有力的依据，目前，矿区已探明（332＋333）金金属资源量34 t。同时，矿区外围磁力异常的分布特征进一步指示该区域内仍具有很大的找矿潜力，航空和地面磁力测量发挥了间接寻找隐伏含铁建造型金矿床的重要作用，是寻找 BIF 型金矿行之有效地勘探方法，对在矿区外围及其他类似地区进行间接寻找隐伏含铁建造型金矿具有非常重要的指导意义。%Production of associated gold with BIF accounts for around 13% of the world’s gold production, almost one third of the gold production in Tanzania is from stripped iron formation gold mine.Through analysis of characteristics of aeromagnetic anomalies in south of Lake Victoria in Tanzania combined with regional geological background,occurrence scope of BIF sequence related to gold ore was interpreted,and then target prospecting area was determined.It was found that the coverage of swampy black soil and weathering was thick in the study region.In addition,we applied magnetic differences significant characteristics of ore rock and surrounding rock to delineate distribution location of iron formation related to the gold mine by ground magnetometry.The results demonstrated that the form of abnormal ΔT was clear with morphology in order and high credibility,which provided a strong basis for drilling engineering arrangement,and the mining area has proven (332+333)34 t gold metal resources presently.Meanwhile,the distribution characteristics of mining area peripheral magnetic anomalies indicated great potential for prospecting in the area of aviation.Air,ground magnetic survey in searching for iron formation gold deposits played an important role,which was efficient exploration methods for looking for the BIF deposits,and the methods had extremely important guiding significance for searching for iron formation gold deposits in the mining area periphery and other similar areas.