New insights on the tectonic evolution of the Miocene gap grabens of Sers–Siliana (Tunisian Atlas) during Neogene to Quaternary: Contribution of chronology of the regional tectonic events

Abstract

The NW-SE trending grabens of Sers-Siliana, located in the Central Tunisian Atlas, show a peculiarity, compared to adjacent grabens, which comes from the existence of an early Miocene sedimentary gap. This paper discusses the structural evolution of these grabens, during the Neogene-Quaternary episode, which have been poorly studied in previous studies. To better understand the chronology of the two grabens, a set of direct and indirect pieces of evidence are given in order. The results show that the collapse is of Aquitanian-Tortonian age which is synchronous with the regional collapse of the Alpine chain foreland grabens. In addition, our field observations show that the E-trending faults affect the incompetent materials (marls) and assured the mechanical junction between these two grabens. The chronology of tectonic events, during the Neogene-Quaternary time, in the Sers-Siliana area coincides with that described at the regional scale for the Tunisian Atlas domain, allowing a better understanding of the role played by the convergence between African and Eurasian plates.

Syn-Collision Folding and Multi-Layers Detachment in the Molassic Basin, Northeastern Tunisia

“…As summarized by several authors, events of widespread deformation in the foreland basin of the thrust sheets are thought to have occurred during the Middle Miocene to present-day times. The Upper Tortonian folding phase which is known as the "Atlassic folding," corresponds to the largest folding across Tunisia [2,3,32,33]. The new field observations show that the evaporitic series of Oued Bel Khedim formation (Messinian) are deposited, with angular unconformity, on the open marine thick series of Kechabta formation (Middle Tortonian) [3] (Fig.…”

“…At Kechabta Neogene basin, the Upper Tortonian folding is proved by an angular unconformity separating the evaporite series of Oued Bel Khedim from the underlying flysch of Kechabta formation. It is the Atlassic folding phase which has shaped the landscape of the Tunisian foreland basin before giving birth to NE-SW folds perpendicular to the NW-SE axis of the regional shortening direction [2,3,32,33]. In the Northeastern Tunisia, this folding event affects the Neogene incompetent materials and forms a NE-SW folds axis direction in Jbel Messeftine, Jbel Kechabta, and Jbel Hkima.…”