Integrated study of surface and subsurface data for prospecting hydrogeothermal basins: case of the Maknassy basin (central Tunisia)

To assess the hydrogeothermal resources of the Haddage region, Tunisia, a multi-disciplinary hydrogeothermal study comprising geological, geophysical, hydrochemical, geothermometric and hydro-geological approaches was undertaken in the Maknassy basin. This approach is important for the determination of the different chemical facies of thermal waters, and to relate them to their reservoirs of origin. It provides a good tool for the delimitation of hydrothermal basins. In fact, the integrated processing of all the existing and newly acquired data confirms that the thermal water of the Haddage region is of meteoric origin. It is deeply infiltrated within the Lower Cretaceous sands and sandstones (Boudinar Formation) and reaches high temperatures (60 degree C) before emerging at the thermal spring in the discharge area as a result of tectonic disharmonies. In addition, a conceptual model of the hydro-geothermic behaviour of the Maknassy aquifer system has been developed.