This contribution presents the first multi-scale geophysical investigation conducted in the Abakaliki and Obubra mining districts (AOMD), southeastern Nigeria, for the exploration of shallowly emplaced (< 50 m) massive sulfide and barite mineral deposits. Raw airborne magnetic data covering the AOMD was acquired and subjected to diverse enhancement routines to facilitate the identification of areas of subtle magnetic anomalies for subsequent ground truthing. The mineralization is mainly made up of galena, sphalerite, and barite. The contrasting physical properties between these minerals and their host rocks make resistivity, induced polarization (IP), spontaneous potential (SP), and magnetic methods ideal to study and delineate the mineralization and possibly locate the ore bodies. Wenner DC resistivity and IP data acquired along the same parallel traverses are inverted using Res2dinv to produce 2D tomography models of resistivity and chargeability. The resistivity and IP models were successful in delineating zones of sulfide and barite mineralization. The ground SP data collected along the same traverses as the resistivity and IP data were interpreted as line graphs. The 1D SP models show a number of central negative anomalies that could be related to sulfide mineralization. These anomalies show fair-to-good spatial continuity and are in close agreement with the result obtained in the resistivity and chargeability model. This study suggests the presence of exploitable mineral deposits in the AOMD and demonstrates the superior interpretative ability of combined geophysical methods over a single geophysical approach.

中文翻译：

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尼日利亚东南部 Abakaliki 和 Obubra 矿区 (AOMD) 浅层块状 (Pb-Zn) 硫化物和重晶石勘探的综合地球物理调查

本贡献介绍了在尼日利亚东南部的 Abakaliki 和 Obubra 矿区 (AOMD) 进行的首次多尺度地球物理调查，用于勘探浅埋 (< 50 m) 块状硫化物和重晶石矿床。获取覆盖 AOMD 的原始机载磁数据并进行各种增强程序，以促进识别细微磁异常区域，以进行后续地面实况调查。矿化主要由方铅矿、闪锌矿和重晶石组成。这些矿物与其主岩之间的对比物理特性使电阻率、诱导极化 (IP)、自发电位 (SP) 和磁性方法成为研究和描绘矿化并可能定位矿体的理想选择。使用 Res2dinv 反转沿相同平行导线获取的 Wenner DC 电阻率和 IP 数据，以生成电阻率和可充电性的 2D 层析成像模型。电阻率和 IP 模型成功地划定了硫化物和重晶石矿化带。沿与电阻率和 IP 数据相同的导线收集的地面 SP 数据被解释为折线图。1D SP 模型显示了许多可能与硫化物矿化有关的中心负异常。这些异常显示出从一般到良好的空间连续性，并且与电阻率和带电率模型中获得的结果非常一致。这项研究表明 AOMD 中存在可开采的矿床，并证明了组合地球物理方法比单一地球物理方法具有更好的解释能力。