New Insights into Geodynamic Evolution of the South-Eastern Termination of the Tunisian Atlas during Early Cretaceous Period from Surface and Subsurface Data: Hydrogeological Implications

Abstract

The Menzel Habib Plain (MHP), the easternmost part of the Southern Tunisian Atlas, exhibits a thick siliciclastic and carbonate succession developed in the Early Cretaceous period. Integration of seismic and gravimetric data coupled with analysis of the syndepositional faults affecting these units proves that the MHP is governed, during this period, by a N-S to NE-SW extensive tectonics induced by the sinistral drifting of Africa with respect to Europe and the beginning of opening of the Eastern Mediterranean Sea. The geodynamic evolution of the MHP is mainly due to the jerky normal activities of the N-S, NW-SE, NE-SW and E-W oriented faults. During extensive period these network of faults architects the sedimentary floor into succession of horst and grabens inducing formation of E-W to NW-SE basins. Seismic lines show that the actual architecture of the MHP obtained after Tertiary tectonic inversion, is that of succession of large synclines separated by narrow anticlines. Porous and permeable unites forming these deep structures host very developed aquifers characterizing the sub soil of MHP and were totally different to the surrounding aquifers of the southern Tunisian margin.