%0 Journal Article
%T Geodynamic Framework of Saline Systems in Eastern Tunisia: Saline Depressions Inherited from the Triassic Intrusions and/or the Messinian Salinity Crisis
%A Elhoucine Essefi
%A Jamel Touir
%A Mohamed Ali Tagorti
%A Chokri Yaich
%J ISRN Geology
%D 2014
%R 10.1155/2014/798706
%X Based on the geodynamic context, two hypotheses of origin of salt in the subsurface of the Sahel area are worth being defended. The first suggests that the halokinesis activities, namely, of the Triassic evaporitic sedimentation, may still be until now influencing the functioning of the saline systems in the Sahel. The second integrates the Sahel area geodynamic evolution in the framework of the convergence between African and Eurasian plates. It suggests a link between the blockage of the subduction between African and Eurasian plates in North Tunisia, the Messinian Salinity Crisis, and eventually the concrete opening and evolution of the playa during the Quaternary. Such a suggestion is materialized by a geodynamic model relating successively these events. This scenario suggests that the Messinian Salinity Crisis constituted huge quantities of salt and/or salty water. This saline subsurface reserve is until now influencing the Sahel behavior as a whole. Through groundwater convergence, huge quantities of salt are accumulated within depressions of the Sahel area. Currently, the convergence of the plate between African and Eurasian plates results in a tectonic activity within these saline systems materialized by the formation of fault spring mounds along preferential orientation ensuring the surface-subsurface connectivity. 1. Introduction Though structures of the previous tectonic activities in the Sahel area are covered by a thick Plio-Quaternary series, geological and geophysical studies (e.g., [1¨C7]) gave a lot of data on the deep tectonic structures and the salt tectonics that was enhanced by the intrusion of the Triassic domes [3, 4]. The geodynamic inheritance in the subsurface of this region is still until now controlling the geology of its surface. For instance, the genesis and evolution of saline depressions in the Tunisian Sahel were strongly controlled by its subsurface, which controlled their formation and evolution [1] and is still until now feeding them with huge quantities of salt through aquifers convergence toward their surfaces [8¨C11]. The aim in this paper is to examine the geodynamic context that controlled the genesis and evolution of saline systems in Tunisian Sahel such as the Mechertate-Chrita-Sidi El Hani system, not only during the geomorphologic shaping and real opening of their depressions but also during previous geological events that had provided a salty context to the subsurface of the Sahel area. This work aims also to study geochemical traces of this salty geodynamics, which may be detected in aquifers. Based on these
%U http://www.hindawi.com/journals/isrn.geology/2014/798706/