Structural and Tectonic Interpretations from Airborne Magnetic and Landsat ETM Data: A Case Study of Yola Arm of the Upper Benue Trough, Nigeria

Structural and tectonic interpretation of the Yola arm of the Upper Benue Trough using the airborne magnetic and Lansat ETM data was carried out to interpret geological features of the Yola arm of the Benue Trough and to infer their relationship with basin architecture, morphology and dynamics, thereby presenting a better understanding of the geology. This work is aimed to determine the magnetic basement depth, establish the basement topography and relief to determine the structural and tectonic features associated with the basin and to infer the effect of such structures on basin geodynamics. The residual data was subdivided into 24 spectral blocks using OASIS MONTAJ software program. Two prominent magnetic depth source layers were identified. The deeper source depth values obtained ranges from 1.56km to 2.92km with an average depth of 2.37km as the magnetic basement depth while for the shallower sources, the depth values ranges from -1.17km to 0.98km with an average depth of 0.55km. The shallow depth source is attributed to the volcanic rocks that intruded the sedimentary formation and this could possibly be responsible for the mineralization found in parts of the study area. Data enhancement was carried out to delineate residual features relative to the strong regional gradients and the more intense anomalies due to basement features, igneous intrusive, etc. Typical techniques applied were computation of reduction to pole, trend surface analysis, upward continuation, etc. The detail in the total magnetic field data supplemented by the range of enhanced maps and images provided the basis for qualitative interpretations in which geological boundaries, lithologies and structural features were delineated. Several lineaments with dominant trends of N-S and NE-SW directions were revealed in the study area. From the economic point of view, the basement depth in the Upper Benue Trough proper and the series of tectonic events associated with the basin do not favour the accumulation and entrapment of hydrocarbons. However, mineral ores are believed to be prevalent in the study area.