Subsurface Structural Mapping over Koton Karifi and Adjoining Areas, Southern Bida Basin, Nigeria, using High-Resolution Aeromagnetic Data

Ikumbur E.B.1,*, Ogah V.E.1 and Akiishi M.2

1 Department of Geology, Benue State Polytechnic Ugbokolo, Nigeria
2 Department of Physics, College of Education Oju, Benue State, Nigeria

*Corresponding Author: ibemsen@gmial.com

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 Vol. 3 No. 2  | October 2019 | Pages 304 – 316

https://doi.org/10.36263/nijest.2019.02.0151

Abstract

ABSTRACT

In this current work, we aim to delineate the subsurface structural trends, determine the depth to basement surface, and provide an illustrative 3D model for its subsurface structure. Four digitized aeromagnetic maps were acquired from the Nigerian Geological Survey Agency, Abuja. The total field aeromagnetic anomalies over Koton Karifi and adjoining areas have been evaluated. In order to map the subsurface structures and estimate the depth to basement surface the spectral analysis method was applied. To achieve such goals, a detailed analysis of the aeromagnetic data for the study area was performed. 2D interpretation was carried out for the aeromagnetic data. The processes used include contouring of the Total Magnetic Intensity (TMI) data, separation of regional and residual anomalies, structural detection methods such as analytic signal, vertical derivatives, and magnetic lineament mapping were used to map the contacts and faults within the study area. The first vertical derivative and the magnetic lineament maps show major geologic lineaments trending in East-West with minor ones trending Northeast-Southwest. In the south-eastern part of the study area, there is a dome-shaped linear feature. The result obtained using the spectral analysis method reveals two source depth models. The depths to deeper magnetic sources range from 2.81 km to 3.24 km with an average depth of 2.90 km. The deeper magnetic source bodies are identified with the magnetic basement. The shallower magnetic sources which range from 0.45 km to 1.81 km with an average depth of 1.13 km could be attributed to near surface magnetic sources which are magnetic rocks that intruded into the sedimentary formations or magnetised bodies within the sedimentary cover. Based on the sedimentary thickness range of 0.45 to 3.24 km, there is an indication that the possibility of hydrocarbon generation in the study area is feasible.

Keywords: Spectral analysis, aeromagnetic anomalies, analytic signal, vertical derivative, depths-to-basement, subsurface structures.

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Ikumbur, E.B., Ogah, V.E. and Akiishi, M., 2019. Subsurface Structural Mapping over Koton Karifi and Adjoining Areas, Southern Bida Basin, Nigeria, using High-Resolution Aeromagnetic Data. Nigerian Journal of Environmental Sciences and Technology, 3(2), pp. 304-316. https://doi.org/10.36263/nijest.2019.02.0151