Water chemistry and isotope composition of the Acquarossa thermal system, Ticino, Switzerland

• Published in: Geothermics Vol. 28; no. 1; pp. 75 - 93
• Main Authors: PASTORELLI, S, MARINI, L, HUNZIKER, J. C
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Science 01-02-1999
• Subjects: Earth sciences; Earth, ocean, space; Exact sciences and technology; Geochemistry; Geothermal water resources; Hydrology; Hydrology. Hydrogeology; Isotope geochemistry; Isotope geochemistry. Geochronology; Isotopes; Mineralogy; Silicates; Switzerland, Ticino; Thermometers; Water geochemistry; Alps; Central Europe; Switzerland; Swiss Alps; basement; carbon dioxide; stable isotopes; O-18/O-16; springs; Europe; rain water; mineral waters; geologic thermometry; depth; C-12; hydrochemistry; deuterium; partial pressure; discharge; hot springs; temperature; thermal waters
• ISSN: 0375-6505; 1879-3576
• DOI: 10.1016/S0375-6505(98)00045-5

The thermal springs of Acquarossa and the nearby mineral springs of Soia have outlet temperatures of 12 degree to 25 degree C, TDS of 2290 to 3000 mg/kg and Ca-SO sub(4) to Ca-SO sub(4)-HCO sub(3) composition. Chemical geothermometers suggest reservoir temperatures close to 60 degree C. P sub(CO(2)) values at depth are estimated to range from 0.3 to 2 bar. delta D and delta super(18)O values indicate a meteoric origin and recharge elevations of 1600 plus or minus 150 m above sea level (a.s.l.) for these thermal and mineral waters. All these waters discharge from the overturned limb of the Simano nappe, probably close to the contact between basement and underlying cover rocks. They therefore represent rain waters that descend slowly, heat at depth and locally rise relatively quickly to the surface, preserving part of their physical and chemical characteristics.