A geophysical investigation that involves the integration of Vertical Electrical Sounding (VES), Electrical Resistivity Imaging (ERI), and Ground Penetrating Radar (GPR) methods was conducted on Papalanto, Ogun River floodplain, a location underlain by sedimentary terrain of Southwestern Nigeria. This research aimed to image the underground lithological units and delineate the shallow geologic structures in order to characterize the area for agricultural suitability throughout the dry season. VES results typically outlined three geologic layers which are topsoil, saturated loamy clay, and alluvium. From 2D inverted resistivity results, three major geologic layers, namely topsoil, saturated loamy clay, and alluvium, were outlined and are in very good agreement with the results attained through VES. The first three layers of 3D inverted resistivity sections display a great amount of variation in the distribution of resistivity at superficial depth, made up of low resistive content. From the GPR survey, three geologic layers were also outlined from the results, namely the topsoil, saturated loamy clay, and alluvium. Consequently, the study location can be said to be semi-competent to competent luxuriant farming land in consideration of the resistivity distribution of the floodplain subsurface. Therefore, VES, ERI, and GPR are very effective geophysical methods for describing and classifying the shallow subsurface in reference to the measured physical properties. Hence, they should be applied in related geophysical investigations for better insight into the geology of the subsurface.

A geophysical method of investigation has been deployed in order to give a quick overview of the nature and the rapidly changing subsurface lithologies that characterized Yikpata, Share, Kwara State, Nigeria. A total of nine (9) vertical electrical soundings (VES), using Schlumberger Array uniformly divided into three groups: basement, basement/sedimentary boundary and sedimentary terrain, and horizontal profiling (HP) using Wenner Array were deployed for this study. The study revealed variation in the subs urface resistivity, thus depicting changes in lithology/rock types along this basement-sedimentary contact zone. The interpretation revealed that the Basement Complex terrain consists of 3-4 geoelectric layers: the topsoil, the weathered, weathered/fractured basement and the fractured basement. Depths beyond ≥ 12 m where the fractured basement occurs can be target for groundwater exploration and structurally controlled mineralization. The resistivity values around the Basement/Sedimentary unconformity zone shows about 3 -4 geoelectric layers. The resistivity values show remarkable characteristics of the basement and the sedimentary terrains and also reflect the rapidly changing subsurface geology in the area. In the sedimentary terrain, 4 geoelectric layers were delineated: Topsoil, clayey sand, sandy clay and clay. Geoelectric sections reveal the variation in the subsurface lithology laterally and vertically. The study has shown that the resistivity method can be an aid to understand complex geologic environments with rapidly changing subsurface geology. Also, the knowledge of the geology of an area is very important in order to make sensible geophysical interpretation.