keywords: Resistivity, lithology, efficiency, delineation, log, correlation
The most widely used geophysical technique for groundwater prospecting is the Vertical electrical sounding. This method determines rock resistivity which is crucial for hydrogeological purposes because it allows differentiation between clayey materials and sandy aquifer. However, interpretation of sounding data has been subjected to ambiguities. In this study, Vertical electrical sounding data have been interpreted and used to delineate lithostratigraphic sequence of the Quatenary deposits of the Niger Delta. The delineated lithologies of geoelectric sequence were correlated with actual lithology based on driller’s log obtained from boreholes drilled at the sounding locations. Efficiency of delineation using resistivity method varied between 63 – 90 %; the high positive correlation (r2 = 0.77) between the delineated lithologies and actual lithologies shows that resistivity method can be efficiently used in delineating lithological sequence. The non-correlation between delineated and actual lithologies in few cases may be linked to equivalence.