Mapping of subsurface structural features in some parts of Anambra Basin, Nigeria, using aeromagnetic data

Aeromagnetic data of some parts of Anambra Basin, Nigeria, covering Illushi, Nsukka, Igumale, Onitsha, Udi and Nkalagu areas were digitally processed, analyzed and interpreted qualitatively and quantitatively. The study was carried out to delineate the subsurface structural lineaments/trends that provide the locales for mineral deposit and hydrocarbon resources and to estimate the depth to magnetic sources/sedimentary thickness of the area. The data were qualitatively interpreted using reduction to equator-inverted (RTE_INV), vertical derivatives (VD), tilt derivative (TDR) filter, lineament density filter and Rose plot. Quantitative interpretation was done using source parameter imaging and Euler deconvolution methods. The results depicted that the study area has enormous structural lineaments especially in the northeast and northwest that showed a high cluster of these lineaments. The results showed that the trends of the structural lineaments have a dominance of NE-SW direction, with ancillary trends in E-W, NW-SE, N-S, NNE-SSW and ENE-WSW directions. The SPI depth result ranges from 318.45 m for shallow magnetic sources to - 11,253 m for sedimentary thickness. The 3D Euler deconvolution depth estimate revealed depths to magnetic sources ranging from - 400 to - 4300 m. The results show good evidence of the presence of the essential factors for the exploration of both mineral deposits and hydrocarbon resources in the study area.