Tectonic evolution of the northern African margin in Tunisia from paleostress data and sedimentary record

Abstract

A reconstruction of the tectonic evolution of the northern African margin in Tunisia since the Late Permian combining paleostress, tectonic stratigraphic and sedimentary approaches allows the characterization of several major periods corresponding to consistent stress patterns. The extension lasting from the Late Permian to the Middle Triassic is contemporaneous of the rifting related to the break up of Pangea. During Liassic times, regional extensional tectonics originated the dislocation of the initial continental platform. In northern Tunisia, the evolution of the Liassic NE–SW rifting led during Dogger times to the North African passive continental margin, whereas in southern Tunisia, a N–S extension, associated with E–W trending subsiding basins, lasted from the Jurassic until the Early Cretaceous. After an Upper Aptian–Early Albian transpressional event, NE–SW to ENE–WSW trending extensions prevailed during Late Cretaceous in relationship with the general tectonic evolution of the northeastern African plate. The inversions started in the Late Maastrichtian–Paleocene in northern Tunisia, probably as a consequence of the Africa–Eurasia convergence. Two major NW–SE trending compressions occurred in the Late Eocene and in the Middle–Late Miocene alternating with extensional periods in the Eocene, Oligocene, Early–Middle Miocene and Pliocene. The latter compressional event led to the complete inversion of the basins of the northwestern African plate, originating the Maghrebide chain. Such a study, supported by a high density of paleostress data and including complementary structural and stratigraphic approaches, provides a reliable way of determining the regional tectonic evolution.