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Precambrian Basement Architecture and Lineaments Mapping of Ado-Ekiti Region Using Aeromagnetic Dataset
Authors: Cyril C. Okpoli, Michael A. Oladunjoye
Number of views: 810
Aeromagnetic dataset over Ado-Ekiti Southwest (sheet 244) was processed to interpret the geology structure and estimate the depth to bedrock of magnetic sources as well as to deduce the basement architecture and their trends. Aeromagnetic dataset were collected, filtered, inverted, and enhanced using appropriate software packages and subsequently employed to generate a model of the subsurface basement topography. The data processing steps involved were Butterworth filtering, reduction to the equator, analytic signal, upward continuation, Tilt angle derivative, Average power spectrum and Euler/Werner deconvolution. The result shows that magnetic intensity from Butterwort ranges from -173.3 to 150.8 nT; Reduction to the pole varies from -213.1 to 314.1 nT; upward continuation at 100m ranges from 156.1 to 142.4 nT and analytical signal varies from 0.0 to 0.4 nT. The magnetic intensity distribution was found to depend on the size, depth of burial, and the thickness of low susceptibility superficial material overlying the magnetite rich crystalline rocks. Tilt angle derivative disclose the presence of fold, shearing, contacts, lineaments with its orientations while the 3D Euler deconvolution > 2000 and dike model fits the Werner function. The average radial power analysis delineated shallow sources ranging from 0.34 km - 0.49 km and deeper sources ranging from 0.45 – 1.25 km. Pseudogravity result is 0.103g/cc which trends in NE-SW direction. The lineaments directions are in NE-SW, NW-SE and E-W directions which are Pan-African, Kibaran and Liberian Orogenies that occurred in the region. Modeled maps of upward continuation, analytical signal, tilt derivative, pseudo gravity average power spectrum and 3D Euler /Werner deconvolution revealed the basement architecture including structural lineaments with its orientations and the depth to the magnetic sources of the study area.