The oldest outcrop and the only Paleozoic terrain in Tunisia is the Jebel Tebaga range in Medenine, dating to the Upper Permian. It consists of a series approximately 500 meters thick, formed by a succession of clay, sandstone, and fossiliferous carbonate layers, featuring two significant massive reef limestone bars built by sponges and corals.
These two bars, prominent in the topography, outline the monoclinal structure of Jebel Tebaga with a 30° southward dip and show an east-west alignment inherited from an ancient orogeny (Hercynian orogeny) dating to the end of the Paleozoic, about 245 million years ago.
The top of the Jebel Tebaga Paleozoic series shows a layer approximately 200 meters thick of red and brown sandstones and clays marking the transition from the Permian to the Triassic. At the base, these sandstones are laterally continuous and represent regressive beach deposits formed when sea levels dropped.
Marine Fossils: This Permian series is well-exposed at Merbah el Oussif and Halg Jmel and is characterized by a very varied paleontological content featuring unique Upper Permian marine fossils in Africa. Alongside fossils of sponges, corals, and bryozoans, there is an abundance of sea lilies (crinoids), Bellerophon layers, several species of Fusulines, the unique Tunisian Trilobite, and one of the last representatives of this type of Arthropod: Pseudophyllipsia azzouzi.
Paleogeography and Paleo-environment:
During the Permo-Carboniferous, a rifting movement split Pangaea into two super-continents: Laurasia to the north and Gondwana to the south, initiating continental drift and the opening of the Tethys. The nature of the sediments and fossils of Jebel Tebaga are precious witnesses to the diversity of the embryonic Tethys and the tropical nature of its waters, reminiscent of today's Red Sea. The two reef masses intercalated in these Permian deposits are the result of successive uplift movements accompanying the rifting.
