Abstract: Based on the analysis of regional seismic profiles and sandbox simulation experiments, the characteristics and formation
mechanism of inverted structures in Chad Bongor basin are discussed and analyzed. The results show that: (1) there are three typical
inverted structures in Bongor basin, which are compressional inverted monocline structure, compressional inverted syncline structure
and compressional inverted anticline structure. Some inverted structures are the inverted fault related folds, which are mainly
developed in the high angle boundary fault zone and the basement Horst tectonic belt in the depression zone. The formation and
evolution of these structures are closely related to existing fault activities; The others are scattered flower anticline structures (looks
liking buckle folds) caused by the upper arch of the strata, which are mainly developed between the slope fault zone or the interior of
graben; (2) The syn-tectonic erosion has an important influence on the evolution of the basin inversion. The erosion promotes the
formation of inversion fold and structural traps in the deep strata, meanwhile, hinders or destroys the evolution of the inversion folds
and structural traps in the shallow strata.

Key words: Bongor basin, inversion structure, syn-tectonic erosion, inverted fault related folds, structural trap