Quaternary Seismostratigraphy and Tectonosedimentary Evolution of the North Tunisian Continental Margin

Abstract

AbstractNorthern Tunisia contains the poorly defined boundary between the Nubia and Eurasian plates. Offshore north Tunisia, the continental margin is interpreted to be part of the North Africa collisional fold and thrust belt system, linking the Maghrebian and the Sicilian‐Apennine chains. The Tunisia margin deforms by a slow NW‐SE trending convergence resulting in a diffuse deformation zone with scarce and scattered seismicity, in contrast to the neighboring regions of north Algeria and north Sicily. The complex recent evolution of this region is poorly known due to the paucity of studies, particularly offshore in the north Tunisian continental margin. Here, we present the seismostratigraphic analysis of the last ~1.8 Ma tectonosedimentary evolution of this area. The seismostratigraphic analysis supports that individual Quaternary depocenters developed syntectonic to faulting and that faulting influenced sedimentation patterns. We identify an abrupt variation in the sediment accumulation rates (SARs) coeval to a change in the strata geometry of the units located near faults at 402 ± 5 ka (mid‐Middle Pleistocene), supporting a change in the rate of faulting associated to contraction tectonics. This change indicates that deformation is controlled by the NW‐SE convergence between Nubia and Eurasia, probably accelerated at the end of extension in the Tyrrhenian back‐arc. Therefore, the current driving mechanism in the Central Mediterranean is possibly lithospheric collision between Nubia and Eurasia.