Application of Electrical Resistivity Method for Groundwater Exploration in a Sedimentary Terrain. a Case Study of Ilara-remo, Southwestern Nigeria
A geophysical evaluation using Electrical Resistivity method for groundwater exploration at Ilara-Remo, southwestern Nigeria was carried out. The investigation involved the utilization of Vertical Electrical Sounding (VES) technique with schlumberger electrode array system. The studied area is located within the sedimentary basin (Dahomey basin) of southwestern Nigeria, ferrigenous sandstone was found to be the major rock type in the study area. The data acquired from the ten (10) VES stations were interpreted using the partial curve matching method and computer assisted iteration technique. The VES results of the data revealed three to five layers which include the topsoil, clayey/sandy clay, clayey sand, conglomeratic sandstones and sandstones/wet sands with resistivity values ranging from 133. The sanstones/ wet sands constitute the main aquifer units. From the overall results the studied area can be classified as prolific zones for groundwater development. INTRODUCTION The availability of quality water resources has always been the primary concern of societies in (Semi Arid and Arid region, even in areas of more abundant rainfall, the problem of obtaining an adequate supply of quality water is generally becoming more acute due to ever increasing population and industrialization.
New stratigraphic, sedimentologic and structural data on the kerri-kerri formation, Bauchi and Borno States, Nigeria
Abstract The Kerri-Kerri Formation is composed of flat-lying to gently dipping basalconglomerate, grit, sandstone, siltstone and clay which unconformably overstep the Maastrichtian Fika Shale and Gombe Sandstone. Five stratigraphic sections (including the type section at Kadi) and six boreholes were studied. The formation attains a thickness of about 200 m at Duku. The heavy mineral suite includes rutile, zircon, kyanite, staurolite, limonite, tremolite, sillimanite, pyroxene, hornblende and tourmaline, which are indicative of derivation from the nearby basement complex and older sedimentary rocks. The rare basal conglomerates, well-bedded siltstones and the presence of shrinkage cracks, clay-supported grits, local channel sandstones and thin horizons of coal and carbonaceous clay suggest a typical fluvial, deltaic and marginal lacustrine environment of deposition. The presence of the pollens Spinizonocolpites baculatus and Monocolpites marginatus among others confirms a Paleocene age for the formation. The interpretation of the surface and subsurface data is consistent with anasymmetrical graben structure of the Kerri-Kerri basin. The western margin of the basin was fault-controlled and active during the deposition of sediments during the Early Tertiary.
A combination of electrical resistivity, seismic refraction, and gravity measurements for groundwater exploration in Sudan
In the savannah belt of central Sudan, near the town of Kosti, a regional geophysical survey has been carried out forming part of a groundwater project. Because of the presence of detectable and significant contrasts in physical properties of the subsoil, integrated use could be made of electrical resistivity, seismic refraction, and gravity methods. In the interpretation of multilayer electrical sounding curves, additional subsurface information such as lithological well descriptions and geophysical well logs is normally a necessity for solving the problems of equivalence. Along a profile in the eastern part of the area studied, where additional subsurface information was scarce, 16 vertical electrical soundings have been made. A preliminary simple mathematical interpretation suggested possibilities for the presence of fresh groundwater in the eastern part of the profile. In order to solve the equivalence problem, seismic refraction work was carried out at some selected places; that yielded additional in...