Abstract: The Bongor Basin is a Meso-Cenozoic intracontinental passive rift basin. Its formation and evolution are influenced and controlled by major surrounding tectonic events. Since the Early Cretaceous, influenced by the separation of the African and the South American plates and the Atlantic extension rifting, the basin began to form and continued to extend and rift, forming a series of NW-SE high-dip steep faults; at the end of the Cretaceous, under the compressive stress caused by the forward high-speed collision in NS direction, between the African and the Eurasian plates, the basin underwent strong reversal which resulted in the strata uplifted, denuded and deformed; then at the end of the Paleogene, local compressive stress resulting from the NW-SE extension of the Red Sea led to slight reversal, and some Paleogene formations denuded; since the Neogene, the basin entered stable thermal settlement. The late Cretaceous structural inversion is an important structural event in the process of the basin formation and evolution, which profoundly affected the sedimentation and hydrocarbon accumulation in the basin. The Late Cretaceous structural inversion is characterized by folding and deforming of the strata. Section description indicates three types of fault related inversion structures:single faulted, double faulted and scattered-flowering faulted. Based on the latest research results on the fault dip and inversion stress intensity and inverted structure characteristics, it is believed that although the Late Cretaceous compressive stress is strong, structure inversion didn't occur in the Bongor Basin due to the phenomenon of "locking" resulted from the excessive dip of the basin fault.

Key words: Bongor Basin, structural inversion, structural characteristics, forming mechanism