Geophysical Investigation of a Fault Zone from Aeromagnetic Data over the Ageva Area of Okene Kogi State, Nigeria

Ahmed Lawal,Avazi Victor,Adamu Abubakar

doi:10.47514/phyaccess.2021.1.1.006

Abstract

High-resolution aeromagnetic data over a part of Ageva fault zone in Nigeria have been analyzed with a view to estimate sedimentary thicknesses within the studied area. The data set of this study area, was subjected to various corrections and interpretation techniques. Regional residual correction was done and the noise level of the data was reduced via upward continuation to a height of 250 m thereby enhancing the reliability of the results obtained. Qualitative interpretation techniques which include: Second Vertical Derivative, Analytic Signal, Tilt derivative were used to delineate the trending pattern of the anomalies in the study area which are in the E-W, NE-SW, NW-SE, and N-S directions. The result suggests that fault zone within Ageva and Owo may be mineralized and also that the faults within Ageva and Ibilo extend by a quarter of their exposed length. The Werner solutions revealed that inferred faults within Owo and Ibilo may have relatively low susceptibilities as compared with others in the study area and the range of the depth extent of linear features is 401.5 m – 982.5 m.

Highlights

The structural interpretation of geophysical data aims at mapping joints and faults by lineament interpretation of processed potential field data or enhanced remotely sensed images
The interpretation of aeromagnetic survey has served as basis for revealing the structural pattern of the basement complex, revealing the shallower structures, tracing lithological contacts and recognizing structures like faults, lineaments, dykes and layered complexes [2]
Data processing is the series of steps taken to remove both signal and spurious noise from the data that are not related to the geology of Earth’s crust

Summary

INTRODUCTION

The structural interpretation of geophysical data aims at mapping joints and faults by lineament interpretation of processed potential field data or enhanced remotely sensed images. The deposit has been folded and faulted and has been affected by regional metamorphism; a general variation in grain size and ore quality from hematite in the west to magnetite in the east is observable, showing an increase in metamorphism eastwards This accounts for the good quality of the ferruginous quartzite in the eastern part of the ridge. The original geometry of the basin may have been by Tertiary uplifts which seem to have affected the northern areas more than the southern half Both the regional dips of the Campanian-Maastrichtian beds and their overall vertical grain size distribution suggest that the original detrital grains were derived from the basement complex of South-western Nigeria. Where the b’s are coefficient and the X’s are some combination of the geographic coordinates

Data Acquisition

Data Processing

Data Interpretation

Findings

CONCLUSION