¹ Dipartimento di Scienze Geologiche, University of Basilicata, Campus Macchia Romana, 85100 Potenza, Italy
² Dipartimento di Scienze Geologiche, University of Basilicata, Campus Macchia Romana, 85100 Potenza, Italy
³ Dipartimento di Chimica e Fisica della Terra (C.F.T.A.), University of Palermo, Via Archirafi 36, 90123 Palermo, Italy

Paolo Harabaglia holds a B.S. in geological sciences from the University of Trieste and an M.S. in earth sciences from MIT. Currently he is a researcher at the University of Basilicata. His main areas of research are seismology and global geodynamics. In particular, he is pursuing an interest in understanding stress diffusion in the crust, with particular regard to its interaction with deep-seated fluids. He is also in charge of a local accelerometric network.

Dr. Giovanni holds a B.S. in geological sciences and a Ph.D. in earth sciences from the University of Bari. From 1993 to the present, he has been a lecturer in geochemistry at the University of Basilicata. From 1994 to 1996, he has been a coordinator of the Basilicata University unit of the national project "Composition and evolution of the continental crust: the crystalline basement in Italy". From 1997 to 1998, he has been a coordinator of the Basilicata University unit of the national project "Modelization of the petrographic and geochemical composition of the continental crust in selected Italian areas." In 1997, he won the "L. Dell’Anna" award, Association International pour l’Etude des Argiles. His areas of research specialization are sedimentary geochemistry and waterrock interaction processes.

Michele Paternoster received his B.S. in geological sciences in 1999 from the University of Basilicata-Potenza, and is currently pursuing a Ph.D. in geochemistry from the University of Palermo. His current interests include water-rock interaction processes, fluids geochemistry, and the significance of earthquake-related anomalies in fluids.

ABSTRACT

This study deals with a chemical survey (major ions and Li⁺, F^–, Br^–, and ) on water samples collected from April 1998 to April 1999, from the Telese thermal spring, southern Italy, in order to investigate possible variations in the chemical composition of the spring. Water samples are of the calcium bicarbonate type, with small fluctuations in outlet temperature (20.05 ± 0.23°C), pH (6.23 ± 0.16), and TDS (2415 ± 35 mg/l). The concentrations of major ions stayed nearly constant, except for . All analyzed waters are saturated or oversaturated relative to calcite and dolomite. The higher saturation indices of the water samples relative to calcite and dolomite observed during the summer of 1998 is interpreted in terms of the lower rainfall during the dry season, inducing a lower supply of CO₂ to the feeding aquifer at depth. The sharp decrease of in the December 1998 to January 1999 water samples during the wet season may be ascribed to a drop in the supply of H₂S from a deepseated source due to a temporary change of stress regime. We suggest that the crustal permeability has diminished in coincidence with the end of a seismic swarm, inducing a change in the sulfate content.