Inferring the Subsurface Basement Depth and the Contact Locations from Aeromagnetic Data over Loum-Minta Area (Centre-East Cameroon)

Jean Aimé Mono,Marcelin Bikoro Bi-Alou,Theophile Ndougsa-Mbarga,Jean Daniel Ngoh,Olivier Ulrich Owono

doi:10.4236/ijg.2018.97028

Abstract

The present study aims to estimate the basement depth and contact locations, deduced from the available aeromagnetic data. The total intensity aeromagnetic (TMI) map was first corrected by the application of the reduction to equator technique. Different edge detection processes, for example, tilt angle derivative (TDR) and its total horizontal derivative (HD_TDR) as well as 3D-Euler deconvolution can determine the edges of these sources. These techniques were carried out on the aeromagnetic data of Minta region (the study area). A correlation was noticed between these techniques indicating that both of them can be attributed in delineating the general structural framework of the area. The aeromagnetic data analysis enables to highlight many deeply-seated structural features trending in the E-W, ENE-WSW and NE-SW directions in this region. The E-W trend is more strongly developed than the other identified trends. Moreover that, two depth methods were applied: analytic signal (AS) and source parameter imaging (SPI). They reflected similar results for estimating the basement depths. From both of them the depth ranges from 150 to 2800 m. Five methods (TDR, HD_TDR, 3D-Euler deconvolution, AS and SPI) for locating magnetic sources indicated that the depth of the basement rocks ranged between 150 and 3000 m as the average range. Also, the comparative study among the 2D magnetic modeling was established by one profile constructing.

Highlights

The magnetic method is one of the most commonly used geophysical tools
The current study investigates the transition zone between the north margin of the Congo Craton (CC) and the North Equatorial Fold Belt (NEFB)
This study is based on the analysis and interpretation of aeromagnetic data to define the subsurface basement depth and contacts location’s inference of the study area

Summary

Introduction

The magnetic method is one of the most commonly used geophysical tools. This stems from the fact that magnetic observations are obtained relatively and cheaply and few corrections must be applied to the observations. The aeromagnetic method has been used in many geophysical studies in Cameroon [4]-[11] to map tectonic structures such as faults, lineaments, fractures and to highlight non-flush geological structures. Such structures may serve as potential hosts for a variety of minerals and may be used as guidance for exploration of the epigenetic, stress-related mineralization in the surrounding rocks [12]. Different techniques (TDR, HD_TDR, 3D-Euler deconvolution, AS and SPI) have been applied on the Minta area to locate the boundaries and the depths of the magnetic sources given the complexity of the geology of the study area in order to have better results.

Objectives

Methods

Results

Conclusion