Spectral Analysis of the Magnetic Residual Anomalies over the Upper Sokoto Basin, Nigeria

Abstract

Spectral analysis of the magnetic residual anomalies over the upper Sokoto Basin northwestern Nigeria was carried On 10 estimate the average depth to the basement magnetic rock in the area. The study area extends from longitude 5 30' N to 12 30'N and longitude 4 00'E to 6 00' E and is covered by eight half degree aero-magnetic maps. The maps were digitized on a 2 km x 2 km grid and later combined to produce a composite magnetic map of the area. The least square polynomial fit method was applied in the region-residual separation. The observed magnetic residual anomalies over the study area was divided up into 60 sections, each of 14 x 14 overlapping grid Works, for the purpose of analysis and interpretation. The spectral plots reveal two layers of magnetic sources. The first layer varies from 0.10km to 0.61km while the second layer depth is rather small to allow for the accumulation of hydrocarbons