Vol20 No.12:3525-3541

【Title】Relationship between gravitational flap structures in the backlimb of anticlinal breakthrough Fault-Propagation Folds: case study of the Southern-Central Tunisian Atlas

【Author】Soulef AMAMRIA¹; Hassen BENSALEM²; Hassan TAIB³; Mohamed Sadok BENSALEM^1*; Riheb HADJI⁴; Younes HAMED⁵

【Addresses】1 Faculty of Sciences Gabès Erriadh City Gabès, University of Gabès, Erriadh city 6072, Tunisia; 2 Higher Institute of Water Sciences and Techniques of Gabès, University of Gabès, Erriadh city 6072, Tunisia; 3 Faculty of Earth Sciences and Architecture, Larbi Ben M’hidi University, Oum El Bouaghi 4000, Algeria; 4 Institute of Architecture and Earth Sciences, Setif 1University, Setif city 19000, Algeria; 5 Faculty of Sciences of Gafsa, University of Gafsa, Sidi Ahmed zarroug 2100, Tunisia

【Corresponding author】Mohamed Sadok BENSALEM

【Citation】Amamria S, BensalemH, Taib H, et al. (2023) Relationship between gravitational flap structures in the backlimb of anticlinal breakthrough Fault-Propagation Folds: case study of the Southern-Central Tunisian Atlas. Journal of Mountain Science 20(12). https://doi.org/10.1007/s11629-023-8265-5

【DOI】https://doi.org/10.1007/s11629-023-8265-5

【Abstract】The development of orogenic belts structures in the Southern-Central Tunisian Atlas is influenced by the evolution of tectonic activities during different phases, which are also closely linked to the formation of gravitational collapse structure. The typical example is that of the northern flank of the Jebel Orbata particularly the Ben Zannouch fold. It is an asymmetrical anticline interpreted by the model of “Fault Propagation Folds”. The development of the Ben Zannouch structures is resulted from landslides, scree falls and inverted layers plunging to the south. The direction of resulted gravitational structure is parallel to the main thrust direction of the Bou Omrane anticline. The thrust activity of Bou Omrane fault is associated to the important paleo-slope facing south and plastic lithology (incompetent marl layers) of outcropped series, facilitates the development of the Ben Zannouch Flap structure. The definition of gravitational collapse structures for the first time in Tunisia particularly in the northern flank of the Jebel Orbata is controlled by many principal structural conditions: fragmentation of the landslide surfaces, rheology and topography. Other regional factors can be distinguished in the Southern-Central Tunisian Atlas as the seismic activity of the pre-existing Gafsa fault reactivated during compressive phases and the weather conditions during the postglacial period.

【Keywords】Southern-Central Tunisian Atlas; Gravitational collapses structures; Paleo-slope; Gafsa fault