Neogene extensional deformation and related stress regimes in central Tunisia

A study of brittle fracturing in onshore Tunisia, including field and seismic data, suggests that the conspicuous NW–SE-trending rift system of the Atlasic domain postdates the main compressional event of Tortonian age (Late Miocene). Therefore, the extensional event would be recent, occurring from the latest Miocene to the Quaternary. From fault-slip data set, we demonstrate that the dominant stress regime coeval with the Neogene rifting was purely extensional, with the extensional stress being oriented NE–SW normal to the average trend of the rift faults, excluding any kind of lateral displacements along the rift boundaries. We discuss the integration of the Tunisian rift-system in the context of the eastward crustal thinning in Tunisia and the development of the offshore Sicilian–Tunisian rift system. The upper-crustal stretching within the Pantelleria–Tunisia domain results probably from the migration of the Ionian block towards the Hellenic subduction zone in the NE.

► We present new tectonic and observational data from central Tunisia.
► The recent extensional event occurred from the latest Miocene to early Quaternary.
► Dominant stress regime was purely extensional, oriented NE–SW.
► Tunisian rifting is coeval with the formation of the Tunisia–Sicily rift zone.
► This upper-crustal extension is due to bulk crustal stretching.