Caratteri idrogeologici ed idrogeochimici del settore meridionale dei M.ti della Maddalena (Appennino Meridionale, Basilicata).

Hydrogeological and hydrogeochemical features of the southern sector of the Maddalena Mounts (Southern Apennines) The study area is located in the central-southern sector of the Maddalena Mounts and is part of a complex geological-structural framework generated by the tectonic overthrusting of the Limestone-Platform Unit onto the Lagonegrese Unit. The terrains outcropping in this area belong to five distinct stratigraphical-structural Units, which are, from bottom to top: Lagonegrese Unit, Limestone-Platform Unit, Liguride Unit and Miocene Flysch Unit. The Maddalena Mounts ridge is an important and complex carbonate hydrostructure of the Marzano Mount-Maddalena Mounts stratigraphical-structural Unit. The study area is bounded, both westward and eastward, by huge tectonic discontinuities along which the Diano valley and the Meandro and Agri valleys have developed, respectively, and, northward and southward, by the alignments of Brienza-Atena Lucana and Casalbuono-Grumento Nova, respectively. The hydrogeological surveys have been carried out in order to define the pattern of groundwater circulation in the aquifer, which is extremely complex and fractioned. For this purpose, hydrogeochemical surveys have been also carried out of the basal water springs and some springs (nearly 30) located at middle-high elevation, by measuring in situ pH, electric conductivity and temperature, and by collecting water samples to determine, in laboratory, the main chemical constituents. Hydrogeochemical data, which have been interpreted also in the light of the geological-structural and hydrogeological frameworks, and the evaluation of the average unit yield for each groundwater basin, have allowed us to suggest reliable hypothesis about the fractioning of the groundwater circulation and, consequently, to define the groundwater basins which feed the main springs of the area.