Tectonics of the West and Central African strike-slip rift system

Abstract

It is essential to intensify research on the strike-slip tectonic system in West and Central Africa to better understand regional tectonic evolution and achieve future breakthroughs in oil and gas exploration. Based on the structural interpretation of extensive seismic data and stratigraphic paleontological analysis of more than 50 wells, this study investigated the tectonic history, sedimentary filling, and evolution of the rift basins in the West and Central Africa, and identified a novel type of intraplate strike-slip tectonic system. It exhibits the following characteristics: (i) the strike-slip tectonic system in the West and Central Africa consists of the Central African Shear Zone (CASZ) and two rift branches, manifesting as an N-shape; (ii) most of basins and rifts are characterized by rapid subsidence at one end and substantial sedimentary thickness; (iii) two types of strike-slip basins are developed, namely the transform-normal extensional basin (TEB) along CASZ and the strike-slip-induced extensional basin (SEB) at each end of CASZ; (iv) two types of basins display their own temporal and spatial evolution history. TEBs underwent two rifting stages during the Early and Late Cretaceous, with a strong inversion at the end of the Late Cretaceous. SEBs experienced three rifting stages, i.e., the Early Cretaceous, Late Cretaceous, and Paleogene, with a weak inversion; and (v) this strike-slip tectonic system was formed under intraplate divergent field, indicating a new type of system. This discovery enhances understanding of the breakup of Gondwana and provides valuable guidance for future oil and gas exploration.