Halokinesis and Diachronism in the Gulf of Gabes

Due to its particular tectonic position in the North African margin, the geological history of Tunisia strongly depends on the relative motion of the African plate, especially since the Jurassic period as a result of the Tethyan opening followed by the Mesogean opening during the Cretaceous period. This extensional regime was followed, during the Late Cretaceous by a compressive pulsation, subject to a controversy among many authors. In order to characterize this pulsation, a study based on the analysis and interpretation of seismic profiles chosen in the southern part of the gulf of Gabes has proven that this Pyrenean event is diachronous. This diachronism could be explained by the resumption of an active halokinetic activity that marked the concomitant sedimentation of the Upper Cretaceous-Paleogene. The initiation and the diachronism of the halokinetic activity are caused by a differential sedimentary loading (downbuilding) spread over time. The latter was triggered since the Senonian distension. However, this diachronism seems to be amplified by a compressive pulsation that marked the terminal Cretaceous.