Structural Interpretation of the Aeromagnetic and Landsat Data of Benin and Its Environs, Southern Nigeria
The study area is part of the Niger Delta, comprising of Benin and its adjoining areas situated in the Gulf of Guinea. The area is located within latitudes 5°30′- 6°30′ N and longitudes 4°30′- 5°30′ E. Structural interpretation of the Aeromagnetic and Landsat Data of Benin and its Environs, Southern Nigeria was carried out to determine depth to the magnetic basement, delineate the basement morphology and relief, and delineate the structural features associated with the basin and to infer the effects of such structures to the general tectonic history and basin geodynamics of the study area. The aeromagnetic and Landsat data were subjected to various image and data enhancement and transformation routines using ILWIS 3.2 Academic and Erdas imaging softwares. Results of the study revealed that the dominant structural trend direction of the study area is in the NE-SW direction. Other lineament trend directions are in the NW-SE, N-S and E-W directions. The drainage pattern is dendritic which is indicative of lithological, structural and topographic differences and also indicative of alluvial rocks, which is typical of the geology of the area that consists mainly of sedimentary rocks. The lineament density map revealed the presence of high-density fracture zones around Atyere and Salawa-Odo areas. Results of the 2-D spectral analysis revealed a two-layer depth model. The shallower magnetic source (D1) has an average depth of 0.37 km while the deeper magnetic source bodies (D2) have an average depth of 3.47 km. The shallower magnetic anomalies is as a result of basement rocks which intruded into the sedimentary rocks while, the deeper magnetic anomalies is associated with intra-basement discontinuities like faults. The average sediment thickness of 3.47 km obtained in this study is significant for accumulation and entrapment of hydrocarbons. However, there seem to be a correlation of the interpreted lineaments with areas of primary mineralization believed to be in the study area.
