Évaluation de la qualité de lʹeau par application de la méthode géoélectrique : exemple de la plaine dʹEl Mida–Gabes nord (Sud tunisien)

The Mida plain, which is part of the North Gabès region (southern Tunisia), is characterized by the deep sandy units of the ‘Continental intercalaire’ (CI) or the limestone of the Lower Senonian. A geophysical survey, by electrical sounding (ES), was undertaken in the studied region to better characterize the deep geological structure of this plain and therefore its aquifer resources potential. The analysis of the results shows that the prospected zone is characterized by the succession of several levels with contrasted resistivities, which are often affected by faults. Among these observed geoelectrical levels, the highly conductor one could host a saline aquifer. Another geoelectrical level corresponding to the resistant bedrock detected at Oudhref horst can contain better-quality water than that of the aquifer detected in the El Mida Graben. In this work, we tried to explain the origin of the salinity of this aquifer. Thus, we hypothesise about a contamination from Jebel Zemlet El Beida through a border fault and another one from the Sebkhet El Hamma. To cite this article: A. Mhamdi et al., C. R. Geoscience 338 (2006).