Arogundade A B, Awoyemi M O, Hammed O S, Falade S C, Ajama O D
Department of Physics and Engineering Physics, Obafemi Awolowo University, Ile-Ife, Nigeria.
Department of Physics, Federal University Oye-Ekiti, Nigeria.
Heliyon. 2022 Mar 5;8(3):e09055. doi: 10.1016/j.heliyon.2022.e09055. eCollection 2022 Mar.
This study analysed aeromagnetic and satellite imagery data over parts of northern Nigeria to delineate magnetic and surface lineaments associated with fault system trends. The aeromagnetic data were analysed using the Fast Fourier transform technique for reduction-to-equator, total horizontal derivative, analytic signal amplitude and Euler deconvolution. Landsat-8 OLI and SRTM data have been enhanced using spatial filtering and hill-shading techniques for the delineation of lineament features. The extracted surface lineaments are denser on the satellite imageries than on the HRAD because the datasets respond to different physical properties of the geological units and features. The location and orientation of the Zungeru/Kalangai fault zone, which extends about 245 km from the Bida Basin Basement to the northern part of Nigeria, correlate with the existing fault on the published geological map and form a conjugate pair with a fault around Kaya. The derived maps revealed the presence of several previously undetected geological lineaments corresponding to faults and folded dyke, striking predominantly N-S, NNE-SSW, NE-SW and NW-SE lacking in previous geological maps. The application of 2D forward modelling revealed the 2D image of the nature of the subsurface, magnetic susceptibilities of rocks and the block boundaries coinciding with the geological lineaments.
本研究分析了尼日利亚北部部分地区的航磁和卫星图像数据，以描绘与断层系统走向相关的磁性和地表线性构造。利用快速傅里叶变换技术对航磁数据进行分析，以进行化极、总水平导数、解析信号振幅和欧拉反褶积。利用空间滤波和山体阴影技术对Landsat - 8 OLI和SRTM数据进行增强，以描绘线性构造特征。提取的地表线性构造在卫星图像上比在高分辨率航空磁测图上更密集，因为数据集对地质单元和特征的不同物理性质有响应。从比达盆地基底延伸至尼日利亚北部约245公里的宗盖鲁/卡兰盖伊断层带的位置和走向，与已发表地质图上的现有断层相关，并与卡亚周围的一条断层形成共轭对。导出的地图显示存在几条先前未被发现的地质线性构造，对应于断层和褶皱岩脉，主要走向为北 - 南、北北东 - 南南西、东北 - 西南和西北 - 东南，这些在以前的地质图中并不存在。二维正演模拟的应用揭示了地下性质、岩石磁化率以及与地质线性构造重合的块体边界的二维图像。
