Halokinesis and structural evolution of the major features in eastern and southern Tunisian Atlas

Abstract

The eastern and southern Tunisian Atlas is marked by the presence of three major faults; the N–S Axis Fault, the NW–SE Gafsa Fault, and the E–W northern Chott Fault. Seismic lines crossing these structures show the existence of significant halokinetics that began in the Early Jurassic. The aim of this paper is to study and better understand the Triassic salt movements, which are mainly linked to periods when the major basement faults were reactivated resulting in extension, compression, transtension or/and transpression. Analysis of the seismic data allows us to conclude that the Triassic salt migration started in the Early Jurassic and continued during the Late Jurassic and the Early Cretaceous. Although these periods are characterized by an extensional tectonic regime, the synsedimentary halokinesis is accompanied by thickening and thinning of the overlying series. Salt remobilization was accentuated during the compressional deformation which occurred from the Late Tertiary to Quaternary and resulted in local diapiric extrusions along the major structural features.