Interpretation Of Aeromagnetic And Landsatetm+ Data Over Part Of The Younger Granite Complex, Nigeria: Implication For Geothermal Exploration

ABSTRACT 

Structural interpretation of Younger Granite complex of northern Nigeria using aeromagnetic and Landsat imagery was carried out to determine the depth to the magnetic basement, delineate the basement morphology and relief, delineate the structural features associated with the basin and to infer the influence of such structures on mineralization in the study area. Also, this study is aimed at determining the geothermal potentials of the area. The application of directional edge enhancement techniques to band 5 of the Landsat-TM data using convolution models in ILWIS 3.2 academic software were to further enhance these linear features. Results of the structural analyses revealed several lineaments at the northwestern, central and southwestern parts of the study area. Trend analysis of the lineaments revealed structural trends in the NW-SE, NE-SW, N-S and E-W directions with the NW-SE and NE-SW been the dominant trends in the area. These trends stand for the positions and directions of the paleo-tectonic fracture zones in the area. High lineament densities were also observed in areas where basement rocks outcrop or are close to the surface. The relationship between lineament densities and Younger granites occurrences in the study area is an indication of tectonic control probably associated with paleo-tectonic structures. This correlation shows that the emplacement of the Younger granite ring complexes may be associated with epeirogenic uplift. The marked relationship between the Younger granites and the lineaments are interpreted as the presence of controlled mineralization in the study area. In most parts of the study area, heat flows were found to be less than 60mWm-2. This implies that the heat flows in the study area differ from region to region, which possibly indicates that the magma conduits were randomly distributed. The heat flow is significantly high in the South-Eastern area with the study area having an average heat flow of 56.06mWm-2. 

Keywords: Magnetic basement depth, Euler deconvolution, Geothermal, Aeromagnetic, Spectral analysis, Curie depth, Younger Granite Nigeria.