Chemical-physical parameters, major, minor, trace elements, isotope determinations (D/H and 18O/16O), dissolved gases, helium isotope and d13CTDC (TDC = total dissolved carbon) composition of groundwater from 8 wells island of Salina (Aeolian arc, Italy).

Geochemical prospection has been a useful tool to understanding the fluid circulating processes over the volcanic island of Salina. The geochemical results have highlighted the existence of reservoirs of both fresh and thermal water although only a few natural manifestations, mainly occurring in submarine environment, provide clues of their existence. The thermal waters, collected at a temperature of 32-36°C, show a typical marine recharge with equilibrium temperatures estimated to be in the range of 120-160°C. As matter of fact, the small island holds relatively large reservoirs of both fresh and thermal waters. The geochemical features of the circulating fluids are driven by water-rock and gas-water interaction processes, while the heat supplied to the geothermal reservoir comes from volcanic rocks that are still cooling down after the end of the last volcanic activity supposed to be not older than 13ky. The collected results allowed us to recognize the contemporary presence of high-temperature geothermal fluids and cold, fresh, waters which geochemical features mark the occurrence of Gas-Water (GWI) and Water-Rock Interaction (WRI) processes responsible for the chemical and isotopic composition of the waters and the dissolved gases. Records include:Chemical-physical parameters, major, minor, trace elements, isotope (D/H and 18O/16O), dissolved gases, helium isotope and d13CTDC (TDC = total dissolved carbon) composition of groundwater from 8 wells island of Salina (Aeolian arc Italy).