Abstract

OJO, J. S; OLORUNFEMI, M. O  and  FALEBITA, D. E. An appraisal of the geologic structure beneath the Ikogosi warm spring in south-western Nigeria using integrated surface geophysical methods. Earth Sci. Res. J. [online]. 2011, vol.15, n.1, pp.27-34. ISSN 1794-6190.

An integrated surface geophysical investigation involving resistivity and magnetic methods was carried out in the immediate vicinityof the Ikogosi warm spring situated in south-western Nigeria with a viewto delineating its subsurface geological sequence and evaluating the structural setting beneath the warm spring. Total field magnetic measurements and vertical electrical sounding (VES) data were acquired along five N-S traverses. Magnetic and VES data interpretation involved inverse modelling. The inverse magnetic models delineated fractured quartzite/faulted areas within fresh massive quartzite at varying depths and beneath all traverses. The geoelectrical sections developed from VES interpretation results also delineated a subsurface sequence consisting ofa topsoil/weathered layer, fresh quartzite, fractured/faulted quartzite and fresh quartzite bedrock. It was deduced that the fractured/faulted quartzite may have acted as conduit for the movement ofwarm groundwater from profound depths to the surface while the spring outlet was located on a geological interface (lineament).

Keywords : magnetic; resistivity; warm spring; Ikogosi; Nigeria.

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