本文为中国有色集团科技计划项目(2017KJJH11/2019KJJH02)资助的成果。
物化探方法寻找隐伏矿床在国内外已得到广泛应用，赞比亚麻希巴矿床属卢弗利安穹隆构造成矿带上一典型层控矿床，赋矿层位为下罗恩群RL6泥岩片岩下部和RL7砂砾岩上部，矿体从浅至深具有氧化带- 硫化带过度特点。为探索深部硫化铜矿体延伸情况，本文利用地球物理(激电极化法、高密度电阻率法和音频大地电磁法)和地球化学方法(土壤测量、偏提取测量)，选择三条剖面进行物化探方法对比研究，物探结果显示硫化矿具有低阻(50~300 Ω·m)、高幅频率(2. 5%~8. 0%)异常特征，高密度电阻率法和音频大地电磁法的电阻率等值线能较清晰地反映基底和RL7底部不含矿地层形态变化，对找矿有良好的指示作用；化探结果显示 Cu元素相关元素为Ag、Bi，在沉积成矿过程中形成Cu- Ag- Bi元素组合，在近地表氧化矿呈“驼峰”高值异常，在深部硫化矿上方呈“偏锋”弱异常，偏提取显示Cu、Co、Bi元素主要是以第二相形式存在，在深部硫化矿上方呈“多锋”弱异常。在方法有效性试验结果的基础上，总结和建立了该矿床类型的地、物、化综合找矿模型，依据物化探异常圈定了深部找矿靶区，经后期钻探工程验证见到两层工业矿体，取得了较好的找矿效果。激电极化法、高密度电阻率法、音频大地电磁法、土壤测量和偏提取测量是实现层控型铜矿经济、快速找矿的方法组合，也为在矿田范围内同类型矿床找矿提供了参考。
Physicochemical methodshave been widely used for locating concealed ore deposits in China and elsewhere．TheMashiba deposit is a typical stratabound deposit in the Luflian dome tectonic metallogenic belt in Zambia. The host beds are the lower part of the RL6 mudstone schist and the upper part of the RL7 glutenite, which are characterized by excessive oxidation zone to sulfide zone from shallow to deep. In order to explore the deep copper sulfide extension，in this paper， geophysical (IP polarization，high density resistivity and AMT) and geochemical (soil measurement， partial extraction measurement) methods are used. Three profiles were selected for the comparative study of geophysical and geochemical exploration methods. Geophysical exploration results show that the sulphide ore has low resistance (50~300 Ω·m)，high (2. 5%~8. 0%) abnormal amplitude frequency characteristics. The high density resistivity method and AMT resistivity isoline can clearly reflect the form of basement and non- ore- bearing strata at the bottom of RL7 which is a good indicator for ore prospecting．Geochemical exploration results show that the related elements of Cu are Ag and Biand Cu- Ag- Bi element combination is formed in the process of sedimentary mineralization. The oxidized ore near the surface shows a “hump” high value anomaly，while the sulfide ore in the deep shows a “partial front” weak anomaly. Partial extraction shows that Cu，Co and Bi elements mainly exist in the form of second- phase Fe- Mn (hydrogen) oxide phase．On the basis of the results of the effectiveness test of the method，the comprehensive prospecting model of the deposit type is summarized and established， the deep prospecting target area is delineated according to the geophysical and geochemical anomalies，and the two- layer industrial orebody is verified by the later drilling engineering．IP method， high density〖JP〗 resistivity method，audio magnetometer method, soil survey and partial extraction survey are the combination of methods to realize the economic and rapid prospecting of strata- controlled copper depositsand also provide a reference for the prospecting of the same type of deposits within the scope of the ore field．
牛聪聪,覃鹏,方科,邓贵安,曾高福,刘蒙蒙.2021.物化探方法在寻找深部硫化铜矿中的应用- 以麻希巴矿床为例[J].地质学报,95(4):1273-1283.
Niu Congcong, Qin Peng, Fang Ke, Deng Guian, Zeng Gaofu, Liu Mengmeng.2021. Application of geophysical and geochemical methods in the search for deep sulfide ores: a case study from the Mashiba copper deposit[J]. Acta Geologica Sinica,95(4):1273-1283.
