Study of a Neogene basin dynamics: The “Bizerte basin”, northeastern Tunisia: relevance to the global Messinian Salinity Crisis

The Messinian sediments of northeastern Tunisia were deposited under an active tectonic setting. They are organized in sequences indicating a transitional deposit from margin – littoral to lacustrine – continental facies. These series unconformably overlie the Serravallian–Tortonian silty clays packages, and are overlain by the transgressive Early Pliocene marl (Zanclean). The presence of evaporitic strata points out to the Messinian Salinity Crisis described in the peripheral basins of the western Mediterranean. The Messinian sedimentation was found to have been closely controlled by transtensive tectonics and differential subsidence at a large spatio-temporal scale. It is organized in sequences typical of a depositional environment controlled by eustatism, tectonic and maybe by climate changes. Despite the existence of some local specific sedimentological characteristics, our results corroborate previous findings that pointed out to the Messinian times as a singular period all around the Mediterranean Basin. Field and subsurface seismic profile data helped reconstructing either the sedimentary or tectonic unconformities existing between the studied Messinian series and older Neogene successions.