Aspetti idrogeologici delle formazioni terziarie di Malta

Abstract

In this work which starts from some geological aspects of the Maltese Island, the litostratigraphic succession of the tertiary rocks is examined in connection with their petrographic nature and with the aquifers they contain. The perched aquifers are located in calcareous and sandy formations or in calcarenitic rocks. In the former the quifers lay upon clays; in the latter the aquifers are supported by levels with finer textural composition or homogeneously ricrystallized, even if they are similar for texture whith other calcarenitic layers. The sea-level represents the base of the main aquifer which locally lay upon clays. Underground water seepage is determined by jointing and karst-phenomena and is facilitated by primary voids enlarged by solution. The chemical composition of the underground waters is variable between the main aquifer and the perched aquifers; in some areas the difference practically disappears. These different conditions are determined by lithological and structural factors which favour or inhibit the diffusion or the mixing of fresh ground waters with sea-water.