Pseudogravimetric anomalies over part of the Gongola arm of the Upper Benue trough, Nigeria

The Gongola arm of the Upper Benue trough in northeastern Nigeria has been extensively studied due to its rich geological history and potential natural resources. However, there has been limited research on the region using pseudogravimetric techniques. Pseudogravimetric transformation is used in converting the total magnetic field intensity (TMI) to pseudogravimetric anomaly by converting at each point of the source distribution the magnetization contrast to density contrast. The pseudogravimetric anomaly has all the usual characteristics of gravity anomaly. This paper presents the results of investigating the pseudogravimetric anomalies over a part of the Upper Benue trough, Nigeria. 2D Forward modelling of some profiles and the derivatives of the Pseudogravimetric anomalies were carried out. The result of the analysis showed the magnetic anomalies to be a result of igneous intrusions, horst/graben structures and magnetic basement topography. The results of the forward modelling show significant variations in the magnetic basement depths across the study area, indicating complex geological structures and potential mineral resources. It also shows the density of the basement rocks to be within the range of 2.64g/cm3 to 2.77g/cm3 which is typically within the range of that of granitic rocks, and the Cretaceous sediment to be in the range of 2.45 g/cm3 to 2.55 g/cm3 . The depths of the Cretaceous sediments vary within the range 300 m to a maximum of about 4 km. These results have contributed to a better understanding of the geological processes and evolution of the trough.