Combination of Tilt-Angle and Euler Deconvolution Approaches to Determine Structural Features from Aeromagnetic Data Modeling over Akonolinga-Loum Area (Centre-East, Cameroon)

Justine Yandjimain,Arsène Meying,Jean Daniel Ngoh,Théophile Ndougsa-Mbarga,Paul Claude Ngoumou,Stéphane Patrick Assembe,Olivier Ulrich Igor Owono-Amougou,Marcelin Bikoro Bi-Alou

doi:10.4236/ijg.2017.87053

Abstract

Aeromagnetic data for center-east Cameroon between the latitudes 3.5° to 4.5°N and longitudes 12° to 12.5°E are used to further study the subsurface area of this part of the geological Province of Central Africa and the Congo Craton. The GIS and GEOSOFT v6.5 softwares are used to treat the data. This analysis enabled us to explore our study area from surface right to the base. The Tilt Angle method is used to delineate geological structures and to estimate the depth. The Euler’s deconvolution method is used to estimate the specific depth of structural contacts. We estimate the northern boundary of the Congo Craton and southern boundary of the Pan-African starting from 3°7'N of West to 3°75'N of East. Its depth is estimated around 2.6 km for deep and 0.1 km for shallow while the direction is WSW-ENE and the NW slope varies from 30° to 60°. We obtain that main and minor lineaments exist throughout, from the surface to the base of the area with their principal direction being SW-NE. We also obtain the vertical gradient contact and the quasihorizontal contact. This is proof of the subduction of the Pan-African belt under the Congo Craton due to the intense collision which caused the rejuvenation of the crust. The main consequence of this collision is the formation of pudding and fold structures, beginning from the superficial part right to the base and which caused the intrusion of schistose, chlorite-schist, quartzite in the micaschist and the intrusions of gneiss and garnetiferous schist in the migmatite. In our study, we highlight the presence of 37 major and 523 minor lineaments that localize the circulation of minerals. The probable slope of the lineaments in the northern part of the region varies from 30° to 60° in a SE direction while in the southern part, and it varies from 30° to 60° in a NW direction.

Highlights

The Magnetic method is one of the best geophysical techniques used to delineate subsurface structures
Combined studies of geochemistry and geology in this area were affected by a series of tectonic events due to the collision between the Pan-African belt and the Congo Craton that formed the structural features of south Cameroon [1] [2] [3] [4] [5]
To the South of our study area, [14] have underlined the major network lineaments identified in the area under study which extend from the SW to NE with a major trend WSW-ENE and can be connected to those identified SW-NE by [6]

Summary

Introduction

The Magnetic method is one of the best geophysical techniques used to delineate subsurface structures. Other studies combining geology and geophysics were conducted in this area to estimate the mineral resources [10] [11] and to estimate the probable position of the Congo Craton boundary [7] [10] [12]. All of these studies showed the main lineaments in this region. Do these major network lineaments extend to our region of study? The use of aeromagnetic data enabled us to study the major and minor structures in their depth and geometries and to highlight the presence of mineral resources

Methods

Results

Discussion

Conclusion