AbstractThe article presents the grain size distribution of soil samples from the Precambrian basement within the purview of the textural properties, deduced transportation history and the numerical assessments using statistical parameters. The fourteen soil samples collected from the study area were subjected to sieve analysis in the laboratory for the determination of their grain size distribution. The statistical parameters’ study includes the graphic mean, skewness, sorting and kurtosis. The result of the analysis of the soil samples ranged from coarse to fine-grained samples, moderately and poorly sorted, positively and negatively skewed and the kurtosis also shows leptokurtic as the most dominant which suggests the samples poorly distributed and moderately sorted at the centre of the grain size distribution. These results also suggest the geological environment of the soil samples could be responsible for the poorly and moderately sorted exhibited by the samples deposited in the location.

The slope method is one of the earliest magnetic depth estimate techniques which can determine the depth to the top of magnetic basement. Reduction-to-pole was applied to the aeromagnetic data of Ilesha southwest, Nigeria with sheet number 243. The data which was originally partitioned into different profiles was later processed to generate reduction-to-pole graph. The contour map of the study area was partitioned into four quadrants, with the highest magnetic anomaly occurring at the third quadrant (southwest region), while the northwest region has the lowest magnetic anomaly. The depth to top for very thin body, intermediate body and very thick body was determined using the Peter's half slope method. These values range between 2.40 km and 10.60 km for the very thin body, 1.8 km to 7.93 km for the intermediate body and 1.41 km to 6.35 km for the very thick body. These results revealed the extent of the depth of the source of the magnetic anomaly that was produced by the aeromagnetic data of the study area.

A geophysical survey using electrical resistivity was carried out in Gbede community within latitude (8˚17’37.7”N-8˚17’49.8’’N) and longitude (4˚20’45.9’’E - 4˚20’58.8’’E) area of Oyo State southwestern Nigeria. The survey was to determine the location and the lateral extent of the suspected Iron Ore deposited in the area using 2D resistivity imaging.using a resistivity meter, Wenner array configuration and electrode spacing ranging from 5 – 25 m was implored in the survey. Five (5) electrical profiles each with 120 m long were conducted within the area. The RES2DINVsoftware was used on the data acquired for processing and inversion. The result of resistivity imaging revealed the lateral continuity of mineral ore deposit within the first layer(top soil) with resistivity values ranging from 395 Ωm to 6619 Ωm at a mean depth of 13m. These values of resistivity suggest the presence of mineral ore in the form of magnetite and hematite which all constituted over 69% of iron in the study area.