Impact of the South Atlantic Opening on the Origin and the Tectonic of the Mamfe, Douala and Rio Del Rey Sedimentary Basins, Geodynamics Implication

Alain Rodrigue Nzeuga,Robert Nouayou,James Derek Fairhead,Françoise Enyegueà Nyam

doi:10.4236/ojer.2019.84017

Abstract

The coastal and intracontinental sedimentary basins of Cameroon owe their origins to the opening of the South Atlantic. Among these sedimentary basins, we can mention those of Mamfe, Douala and Rio Del Rey, which are the subject of our current study. These were formed following geodynamic processes between the periods from the lower Cretaceous to the Neogene. These processes have significantly affected the basement of these basins leaving as consequences of multiple faults which would in their turn favor a rise of the magma towards the surface which then cooled to give birth to the volcanic rocks which exist there today. A study of the impact of the opening of the South Atlantic on the tectonics of these basins will be made from a geodynamic approach, relying in the first time on a qualitative and quantitative analysis of the anomaly map of the total magnetic intensity field reduced to the pole of each basin, then in a second time on the interpretation of the 2D geological models realized on a profile chosen on the anomaly map of the total magnetic intensity field reduced to the pole of each basin. At the end of this study, we will show that the opening of the South Atlantic has similarly impacted the structure of the three basins and the results of the spectral analysis show that the oceanic crust is thinner than the continental crust.

Highlights

The history of Cameroonian sedimentary basins and the evolution of their tectonics begin in the early Cretaceous with the break of the Pangea
A study of the impact of the opening of the South Atlantic on the tectonics of these basins will be made from a geodynamic approach, relying in the first time on a qualitative and quantitative analysis of the anomaly map of the total magnetic intensity field reduced to the pole of each basin, in a second time on the interpretation of the 2D geological models realized on a profile chosen on the anomaly map of the total magnetic intensity field reduced to the pole of each basin
These intrusions are in most cases oriented west south west-east northeast, north west-south east, south west-north east and suggest that during the opening of the South Atlantic, the tectonic movements in these basins would have caused the break of the basement and favored a rise of the magma along the above directions, which would have cooled to give birth to volcanic rocks observed in them

Summary

Introduction

Following convective movements in the Earth’s mantle, Earth’s tectonics has evolved considerably to the formation of the seven plates and multiple islands that we know today Another closely related phenomenon is the opening of the South Atlantic, whose evolution over time would have given rise to the Mamfe, Douala and Rio Del Rey sedimentary basins. The geophysical works carried out in these basins aimed at the structural study and the realization of the anomaly and geological maps from the gravity, electrical, aeromagnetic and magnetotelluric data These include those of Dumort [20], Collignon [21], Petters et al [22], Fairhead et al [23], Manguéllé-Dicoum et al [24], Poudjom Djomani et al [25], Benkhellil et al [26], Ndougsa Mbarga [27], Nouayou [28], Brownfield and Charpentier [29], Nvondo Owono [30], Nguimbous et al [31], Ndikum et al [32], Koum et al [33], Nzeuga et al ([34], [35], [36])

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