Hot waters on Pantelleria Island; geochemical features and preliminary geothermal investigations

Thermal and cold waters from Pantelleria island were collected and analyzed for their chemical and isotopic composition at different times during 1980, with the aim of assessing prospective sources of energy. The waters studied are mostly chloride -- sulphate -- alkaline. The specific processes responsible for the observed composition are: admixture of sea water; dissolution of alkaline carbonates; and precipitation of earth-alkaline carbonates. Water -- rock interaction is deemed responsible for the enrichment of Na and K as hydrogen carbonate. Observed compositional changes with time at some sampling points and comparison among different springs indicate that water chemistry cannot b related to one homogeneous water body only, although one broad chemical process is likely to be in control. Estimated temperature falls in a narrow range, 130 -- 170/sup 0/C, after the outlined processes have been accounted for.