Structural and Tectonic Interpretation of Nkalagu and Environs Using High-Resolution Aeromagnetic Data

Abstract

The aeromagnetic survey carried out by the Geological Survey of Nigeria between 2003 and 2010, provided high-resolution aeromagnetic data used in this study. The study area is Nkalagu and its environs. It lies within latitudes N6o00 and N6o30 and longitudes 8o00 E and E. The geology of the study area is predominantly the geology of the Lower Benue Trough. The purpose of the study is to determine the depth of the basement and delineate the basement morphology and structural features associated with the subsurface of the study area using the structural and tectonic interpretation of aeromagnetic data. This will create indebt knowledge of the geology of Nkalagu and its environs. The Aeromagnetic data obtained were subjected to various data preprocessing enhancement techniques these include relief imaging, vertical and horizontal derivatives, analytic signal, apparent susceptibility mapping, automatic gain control, and spectral analysis. Results of the study revealed lineament with trend directions in the N-S, NE-SW, NW-SE, and E-W, with the NW-SE trend being dominant. When subjected to 2-D spectral analysis, it revealed a two-layer depth model; the shallow magnetic sources and the deep magnetic sources with average depths of 1.041 km and 3.574km respectively. Similarly, the average sedimentary thickness of the study area was estimated at approximately 3.6km.