HYDROGEOLOGICAL IMPLICATIONS OF THE RESISTIVITY DISTRIBUTION INFERREDFROM ELECTRICAL PROSPECTING DATA FROM THE APULIAN CARBONATE PLATFORM

Electrical and magnetotelluric surveys have been performed on the Apul ian carbonate platform to study the deep coastal karst aquifer. The su rveys extend to a depth of about 7 km, to give a complete hydrogeologi cal understanding of the area. The problems of interpreting regional g eophysical data in highly heterogeneous carbonate rocks are extensivel y analyzed. This study suggests that the aquifer is generally confined at both the top and the bottom by more compact carbonate rocks and ha s a maximum depth of about 2 km. Also, seawater invasion is both areal ly and vertically limited. The possibility that dolomite rocks, presen t in the 2-5 km depth range, could also hold low-salinity waters is di scussed. All the hydrogeological features of the investigated area are found to be mainly dependent on the tectonic evolution of the carbona te platform.