Subsurface investigation of geological structures from magnetic method in parts of Kangiwa Gwandu Formation northwestern, Nigeria

Abstract

The future development of hydrocarbon or mineral exploration is planned in the inland basin located in the southeastern part of Gwandu formation, Sokoto Basin of about 89 km2 from Birnin Kebbi northwestern Nigeria. The area under investigation is located between latitudes 12° 24′00″N to 12° 24′00″N and 4° 04′00″E to 4° 24′0.12″E. The study are comprises with a total area of approximately 1.02 km2. The main target of the present study is to understand the subsurface geological structures and its relationship to known geology of Gwandu formation. To achieve this, magnetic survey has been used. A total of seven magnetic transverse lines were established in an NWSE direction in the study area covering 250 m by 250 m. Data were taken and recorded using ACZ-8 Proton Precession magnetometer; the data were presented inform of magnetic profiles, which aided the qualitatively interpretation. The necessary correction concerning daily variation, regional gradient, time variations have been applied. The total magnetic anomaly map (TMI) has constructed and reduced to the magnetic equator (RTE). The results of this study revealed information of multiple parameters conductive to subsurface geological features on their high and low magnetic anomalies which were interpreted as competent and weak zones in the area of study. The study area was also characterized by completely varying magnetic anomaly amplitudes across the field and the results gave values for the total component measurements of the ground magnetic anomaly that varied between a minimum negative peak value of about -3200.6 nT and a maximum positive peak value of about 43000.9 nT.