One of the vital roles played by both magnetic and radiometric surveys is identification and delineation of mineral deposits. The study area, Imeri, which lies between latitude 6 °45′N to 6 °48′N and longitude 3 °58′E to 3 °59′E, has been established for bitumen deposition. The responses of mineral deposition to different geophysical methods differ from place to place due to variation in climate and bedrock composition. In this study, two geophysical techniques—magnetic and radiometric methods—were adopted to investigate the magnetic anomalous and radiometric flux responses around the bitumen deposit area. The study also intends to establish a model-like relation between the radiometric parameters and the magnetic anomaly observed. Statistical inferences for the established relations were deduced using the t-test at 0.05 significance levels. The result obtained showed that uranium and thorium concentration responses along the two traverses were in good agreement with that of magnetic intensity. The claim was accounted for based on the correlation result, which ranged between 74%–79% and 84%–89% for uranium and thorium, respectively, with magnetic intensity along the two traverses. In order to validate the claim, the t-test was used. The result obtained showed that there exists no significant difference between the two geophysical methods; the result for the t-test has critical value > calculated value (p-values > 0.05). Based on this, the empirical relations were deduced for magnetic anomalous response and radiometric parameters. This work has therefore proven the two techniques to be versatile for bitumen prospecting in the study area.

Ground based magnetic survey conducted between longitude 06O 55I 51IIN -06O 55I 54IIN and latitude 03O 52I 06IIE -03O 52I 4.8IIE (Olabisi Onabanjo University) remarkably revealed a consistent subsurface NW -SE structural azimuth of localized discontinuities within the shallowly buried heterogeneous basement rocks, which at exposed locations are composed of strongly foliated granite gneiss and migmatite-gneiss with veins and veinlets principally orientated in NNW -SSE direction. Magnetic survey of the area was preceded by site inspection to avoid metallic objects interferences. Field procedure in the area involved Cartesian gridding, base station establishment, data acquisition at gridded points, and repeated bihourly diurnal checks at the base station. At the processing stage, diurnal variation effect was aptly removed before subjection to Kriging (gridding). The gridded data was then prepared as input for Forward Fourier Filter Transform (FFT), which upon definition and implementation enabled Butterworth filtering of isolated ringing effects, reduction to the equator (RTE) for geomagnetic correction, and the use of Gaussian and Upward Continuation filtering for regional magnetic intensity trend determination. Removal of the regional magnetic intensity (RMI) from the total magnetic intensity (TMI) resulted in the derivation of the residual anomaly. Enhancement filters adopted for better resolution of the residual magnetic gradient include analytical signal (AS), tilt-angle derivative (TDR), vertical derivative deconvolution (VDD), and the first vertical derivatives (FVD). TMI and RMI values range between 32925nT -33050nT and 32935nT -333050nT respectively, while the residual gradient ranges between 15nT/m and 10nT/m; AS ranges between 0.28nT/m and 4.1nT/m; and TDR ranges from -1.4nT/m to 1.4nT/m. Source depth calculation estimated from power spectrum analysis and Euler deconvolution ranges between 1m and 15m. Composite overlay of magnetic maps revealed jointed and faulted zones within the area; exhibiting a NW-SE principal azimuth of Liberian orogenic impress, which are in consistence with the foliation direction of the jagged foliated bedrock with an estimated maximum overburden of about 15m. The structural significance of this area as a prospective hydro-geological centre, and as an undesirable spot for high-rise building has been accurately evaluated from research findings. Application of integrated geophysical approach, complemented by detailed geological studies may furnish greater information about the subsurface structural architecture.

The present study aims to assess environmental pollution using the resistivity method and geological logging technique over a municipal dumpsite of Ijagun Ijebu Ode, underlain by the Afowo Formation within the Dahomey Basin southwestern Nigeria. Forty vertical electrical resistivity soundings stations and six 2D electrical resistivity imaging profiles using Schlumberger and Wenner array respectively with maximum spread-length of 40m at each sounding and profile length of 60 m and 120 m and one borehole log were carried out. Three geoelectrical layers were obtained in the control area, their resistivity values with their corresponding depth of sediment materials is 126 Ωm – 724 Ωm at depth range 0.9 m – 1.1 m (topsoil), 608 Ωm – 2517 Ωm at depth range 3.5 m – 17.7 m (sandy layer), and 800 Ωm – 6046 Ωm (dry sandy layer). Along with the 2D resistivity imaging profiles over the control (1 and 2), four geo-electric layers characterized by Resistivity values range of 40 Ωm – 126 Ωm (loam), 135 Ωm – 418 Ωm (loamy sand), 500 Ωm – 1500 Ωm (sandy), and >3000 Ωm (dry sand) were revealed. The lithology recovery from the logging techniques shows the subsurface is underlined chiefly with sand, which shows a significant correlation with the geophysical method. The lower values of resistivity at the dumpsite are clear evidence of the subsurface contamination of the sandy layer. The 2D images revealed the contaminated zone thickness ranges from 2 m in the northwest to 25 m in the southeastern part. The protective capacity map derived from the VES showed that the dumpsite is underlain by poorly protected sandy lithology, prone to leachate infiltration. Relocation of the dumpsite to a better protected environment or underlining the present area with an impermeable geotextile layer would halt further leachate invasion into the subsurface.

Geophysical techniques are powerful tools in depth estimation of minerals deposits. This survey was carried out to evaluate the nature and  depth of mineral deposits near the Sports complex of Olabisi Onabanjo University (OOU), Ago-Iwoye.’. A total of five (5) Vertical Electrical Soundings (VES) points were investigated using Pasi Terrameter. The spread across the area using the Schlumberger  configuration was with a maximum current electrode separation of 100m. The results obtained were interpreted quantitatively and  qualitatively using partial curve matching and computer iteration programs known as WINRESIST and SURFER 11. Also, forty one (41) survey profiles were taken at a station interval of 5m using the GEM Magnetometer to acquire the Total Magnetic Intensity reading. The Guassian filter-Oasis Montaj was used for the computation of regional field from the observed TMI readings of the area. The geologic andstructural map reveals a few visible fractured zones imbedded in the migmatite-gneiss deposits which spread from the northwest to the southern and eastern part of the study area and the granite gneiss was seen around the Southwestern and Northern parts. The delineated fractures could potentially serve as geologic traps for mineral localization. The 2D radial average power spectrum indicates that, the northeast part of the mapped area has a depth of 4.5mand a depth of 13m at the eastern part. It can be seen that the depth are shallow and there are visible outcrops at the study area.The approximate depth to the mineral deposit was determined using the standard Euler solution to be around 13 m and the elevation range obtained varies between 37 m – 50 m. The correlation of the electrical and magnetic techniques shows that both methods are able to give the estimated depth of shallow mineral deposit which range between 13 m – 18m. Keywords: Euler solution, Geophysical Techniques, Lithology, Total Magnetic Intensity, Vertical Electrical Sounding.

The research aim is to determine the organic productivity and hydrocarbon potential of the exposed shale lithology along Uzebba road and Bawa hills near Auchi, Southwest Nigeria.Twenty two (22) shale samples were acquired from the study area; twelve (12) from the outcropping section along Uzebba road, and the remaining ten (10) samples obtained from Bawa hills. The samples were then subjected to organic geochemical analysis using Total Organic Carbon (TOC) and Rock Eval Pyrolysis to evaluate the organic enrichment, organic quality and thermal maturity espectively.Total Organic Carbon (TOC) content of the twenty-two samples ranges from 3.42 – 4.88 wt. %, affirming a high organic enrichment. Shale samples from Uzebba segment and Bawa hills falls within the Type I and Type II Kerogen class respectively. The former is indicative of immature – sub mature organic matter with no hydrocarbon formation prospect whilst the latter exhibits great hydrocarbon (oil) generation potential Thermal maturation assessment for both samples apparently ranges from immature to mature organic matter. From the Rock-Eval pyrolysis result, all the twenty-two (22) samples were confirmed to be organically enriched. However, the type I kerogen of Bawa at favourable geothermal gradient can potentially serve as a suitable source rock for petroleum generation.