Halokinesis in the Tunisian salt province and the influence of the kinematics of the inherited Tethyan faults systems on the evolution of the Jebel Ech Cheid salt body (Northern Tunisia)

Abstract

The Jebel Ech Cheid salt structure is located in the salt province of Tunisia. It lies to the south east of the archaeological site Dogga / Teboursouk. The Jurassic to Cretaceous North Tunisian salt province evolved above the Triassic thick salts. Extension is began from late Triassic to early Cretaceous Episode resulted in development of salt structures complex system, which in early Cretaceous culminated in “diapirism” and salt extrusion onto the basin floor. Within both basin flanks of Jebel Ech Cheid salt body, we observed syn-sedimentary evidences of early Albian normal faults, chaotic folds, olistoliths… Jurassic and early Cretaceous subsidence were connected to relatively minor salt movements in the Jebel Ech Cheid area, subsequently major extensive episode and salt movements observed in the Jebel Ech Cheid area were between middle Cretaceous to early Senonian times. The sedimentary basin architecture is essentially structured by inherited normal faults system set identified through seismic profiles: it is a synthetic and antithetic rollovers system in the southern part, combined with Teboursouk fault system in the North. The Mesozoic built was the first factor responsible to the evolution of the sedimentary basin and the birth of the salt body of Jebel Ech Cheid. The next compressed major phase was caused by the late Cretaceous to upper Eocene positive inversion. So, in the Oligocene time there is a stretching period. At the end, the salt movements were influenced by the Tortornian and quaternary folding. The delamination and folding of the overburden salt cover facilitate the development of the salt sheets. The Jebel Ech Cheid salt structure has been subjected to asymmetric thrusting, possibly enhanced by gravitational gliding due to the orientation of the major inherited normal faults (NE-SW) and the role of the principal compression direction (NW-SE). The salt movements of Jebel Ech Cheid were influenced by many tectonics phases; so, we consider that is a salt dome with salt extrusion like salt « glacier » in the initial period was rooted, evolved to a complex structure uprooted after the Tertiary/early Quaternary folding

AAPG Datapages/Search and Discovery Article #90226 © 2015 European Regional Conference and Exhibition, Lisbon, Portugal, May 18-19, 2015