Contribution of Geophysical Prospecting to the Assessment of Hydrothermal Potential in the Region of HmeÔma (Central -Western Tunisia)

Abstract

By its geographical location in Central-Western Tunisia and its geology, the studied area is considered as an important geothermal province. Indeed, aptian reefal limestones, characterized by intense fracturing and important karstification, confer them the property to be a regional thermal aquifer.

This multidisciplinary study, based on geological, geochemical and especially geophysical investigation has been carried out to evaluate the hydrothermal potential of the HmeÔma's area. To better characterize the geometry of this regional thermal aquifer, we used geophysical methods.

The geophysical methods (electrical and magnetotelluric), allowed us to study the geothermal aquifer and to have an idea about its structure in depth. This is illustrated by geoelectrical and electrostratigraphical cross-sections passing by geological structures of the region. Isobaths and in isopach maps were established to delimit and to follow the lateral evolution of the reefal limestones. Furthermore, this geophysical study, enough advanced, shows all discontinuities (faults) and tectonic structures (anticlines, synclines and Triassic diapirs) that influence the hydrodynamism of the thermal water.

The synthetic approach integrating all data allowed us to delimit the favourable area for thermal water exploitation.