Study on the inversion structure of rift system in central and west Africa

In the process of plate tectonic movement, extensional faults and conversion faults occur.In the process of studying the rift system of central and west Africa, by comparing the basin types and fault plane distribution characteristics of Africa and South America on both sides of the Atlantic ocean, it can be seen that the main continental fault on both sides of the Atlantic ocean and the fault developed at the mid-ocean ridge on the bottom of the Atlantic ocean belong to the conversion fault.The function of conversion faults is to regulate the difference in the moving speed between blocks in the contemporaneous structure. Therefore, the conversion faults developed in these three regions are similar and interrelated in terms of structure type, structure style, block movement mode and direction.The main transference faults in various regions play a role in regulating the differences of continental extension and inversion tectonic rates in the Atlantic ocean, Africa and South America.

There are two transition fault systems in the rift system of central Africa and west Africa. Under the joint action of these two transition fault systems, extensional basins and transition basins are mainly developed in the rift system of central and west Africa. Moreover, these two transition fault systems play different roles in different stages of the tectonic movement of the whole African plate.

After detailed interpretation of seismic data, it can be found that there are mainly fault-controlled inversion structures in Doseo basin and Doba basin.

As a representative of transition basins, fault-controlled inversion structures are widely developed in the Doseo basin, but they have different distribution characteristics.Among them, fault-controlled inversion structures with large inversion ranges are distributed near large faults in the basin, while fault-controlled inversion structures with small inversion ranges are far away from the structural units of the main controlled faults, the inversion structures have a small amplitude, and the stratigraphic reconstruction fragmentation degree is relatively weak. The inversion structures with weak inversion are mainly developed in the middle, western depression and southern uplift of Doseo basin.And as the representative of the extensional basin. In Doba basin, fault-controlled inversion structures are mainly developed, and the structures with high inversion rate are distributed in the central depression zone of the basin. The low inversion rate structures are distributed in the uplift and slope areas in the western part of the basin. By studying the development types and distribution locations of inversion structures in basins, it can be known that different types of basins have different transformation conditions during inversion.

Therefore, by comparing the differences in the plane and vertical characteristics of the inversion tectonic development of Doseo and Doba basins, as well as the studies on the eastern and western and non-other basins, it can be concluded that during the tectonic evolution of the rift system in central and west Africa, especially during the transition inversion stage, there were significant differences between the transition basin and the extensional basin.