Sedimentary evolution of the late Cretaceous - Eocene deep carbonates series of the foreland Magrebian chain. The Tellian domain of northern Tunisia

Abstract

This paper aims to give an overview of the Upper Cretaceous – Eocene in the Tellian domain of the Magrebian chain in Tunisia. The sedimentological studies of the carbonates of this time interval, in the Fernana - Ain Draham area, offer a better knowledge of the Tellian foreland. Stratigraphic analysis of ten sections located in the structural units (Autochthonous, Para-autochthonous, and the allochthonous, Ediss Unit, Ain Draham - Adissa Unit and Kasseb unit) brings new results. The facies analysis of the nappes zone reinforces the definition of the allochthonous units that have undergone planar displacements during late Tertiary phases. The depositional setting evolutions during the Late Cretaceous - Eocene period testify to an area in the process of deformation. Since the late Cretaceous (Maastrichtian), the abundance of older dismantling rocks in the allochthonous units is interpreted as a synchronous shortening of the basin. The clastic deposits attributed to mélanges chaotic deposits forming events layers testify two tectonic stages of the early foreland basin formation with details: the upper Cretaceous (Gansseri Biozone) and the early Eocene (Lutetian). The studied deposits outcropping in the Tellian domain (part of the Maghrebian chain) invoke the earliest stage of synchronous compressive syn-sedimentary tectonics of the subduction of Europe over the African plate southern branch, as observed in the Mediterranean rim.