Structural Trends and Spectral Depth Analysis of the Residual Magnetic Field of Naraguta Area, North Central, Nigeria

The results of a magnetic study of the Naraguta area, North Central Nigeria are presented here. Regional-residual separation was carried out using Least Square method. The resultant regional map revealed a regional trending in a NW-SE direction. The magnetic residual values range from -487.828nT to +405.447nT. Short to moderately long dislocations were found in the residual magnetic map. Several magnetic closures of various sizes were also noticed. While the discontinuities indicate the presence of minor to moderately long geologic fault in the area, the closures depict the type and size of the anomalies that lie beneath the area. Magnetic lineaments trending in a NE-SW direction has been identified to pass through the study area. This concentration of magnetic lineaments may be connected with the occurrence of younger granites in the study area since almost all known younger granite complexes lie within the region dominated by this trends. Also a prominent ENE-WSW anomaly low has been identified in the Jos-Bukuru complex. The trend of the anomaly is believed to be roughly parallel to that of the main structural feature of the Benue trough indicating the probability that the Benue trough and the younger granite intrusive are related considering the stress, which initiated the formation of these features. 2-D spectral analysis of the magnetic anomalies over the area has been carried out in an effort to estimate the depth to magnetic sources. The result shows that the deeper sources have an average depth of 2.03 Km while the shallower sources have an average depth of 265m.