BS Geophysical and Consultancy Ltd., Ilorin, Nigeria.
Department of Geophysics, Federal University Oye-Ekiti, Oye-Ekiti, Nigeria.
Sci Rep. 2021 Nov 4;11(1):21646. doi: 10.1038/s41598-021-00829-y.
High resolution aeromagnetic anomaly and topographic data using enhancement filtering techniques have resulted in better understanding of the nature of structures at the margins of the Middle Niger Basin. Due to the lack of structural data, the gold deposits within the margins of the Middle Niger Basin were variably excavated, leading to land degradation. The newly-produced structural map highly constrained the mineralization, which makes the study area and its periphery safe for gold exploration. Structural map has been produced from the integration of derivative maps to assess the pattern of surface and subsurface structural features within the studied area. The structural map unravels structural features with major and minor structural trends, in addition to a prominent crustal partitioning, characterized by the Ifewara shear zone. These structural features correlate very well with known gold mineralized locations and also predict new zones for structurally controlled gold and associated mineralization. The structural patterns are directly related with tectonic episodes in the basement. In fact, the Ifewara shear zone appears more pronounced on the total gradient and 3-D Euler deconvolution maps, which reveal various lineaments within the shear zone. The topographic maps (digital elevation model) clearly shows the surface morphology of the region under study while the resulting shaded-relief map reveal the continuity of the deduced magnetic lineaments that coincide with the valleys of River Niger which exploits zones of weakness from the lineaments. The results suggest high sensitivity of fluvial network to deduced lineaments with possible significant implication for alluvial gold mineralization.
利用增强滤波技术获得的高分辨率航空磁异常和地形数据，使我们更好地了解了尼日尔河中上游流域边缘构造的性质。由于缺乏构造数据，导致该流域边缘的金矿开采情况各不相同，进而引发了土地退化。新生成的构造图对成矿作用进行了严格限制，使得研究区及其周边地区成为安全的金矿勘探区域。通过整合导数图来制作构造图，以评估研究区内的地表和地下构造特征模式。构造图揭示了主要和次要构造趋势的构造特征，以及明显的地壳分区特征，其特点是存在 Ifewara 剪切带。这些构造特征与已知的金矿化位置非常吻合，并且还预测了新的受构造控制的金矿和相关矿化带。构造模式与基底中的构造事件直接相关。事实上，Ifewara 剪切带在总梯度和 3D 欧拉反演图上更为明显，这些图揭示了剪切带内的各种线性构造。地形图（数字高程模型）清晰地显示了研究区域的地表形态，而生成的阴影 relief 图则揭示了推断磁线性构造的连续性，这些磁线性构造与尼日尔河的河谷相吻合，利用线性构造中的薄弱带进行开采。结果表明，河流网络对推断线性构造具有高度敏感性，这可能对冲积金矿化具有重要意义。
