New Chemical and Original Isotopic Data on Waters from El Tatio Geothermal Field, Northern Chile
Geochemical Journal, Vol. 39, pp. 547 to 571, 2005 New chemical and original isotopic data on waters from El Tatio geothermal field, northern Chile GIANNI CORTECCI,1* TIZIANO BOSCHETTI,2 MARIO MUSSI,1 CHRISTIAN HERRERA LAMELI,3 CLAUDIO MUCCHINO4 and MAURIZIO BARBIERI5 1Istituto di Geoscienze e Georisorse, Area della Ricerca CNR, Via Moruzzi 1, I-56124 Pisa, Italy 2Dipartimento di Scienze della Terra, University of Parma, Parco Area delle Scienze 157/A, I-43100 Parma, Italy 3Departamento de Ciencias Geológicas, Universidad Católica del Norte, Avenida Angamos 0610, Antofagasta, Chile 4Dipartimento di Chimica Generale ed Inorganica, Chimica Analitica, Chimica Fisica, University of Parma, Parco Area delle Scienze 17A, I-43100, Parma, Italy 5Dipartimento di Scienze della Terra, “La Sapienza” University of Roma, Piazzale Aldo Moro 5, I-00185 Roma, Italy (Received December 1, 2004; Accepted June 1, 2005) The El Tatio geothermal field is located at an height of 4200–4300 m on the Cordillera de los Andes (Altiplano). Geysers, hot pools and mudpots in the geothermal field and local meteoric waters were sampled in April 2002 and analyzed for major and trace elements, δ2H, δ18O and 3H of water, δ34S and δ18O of dissolved sulfate, δ13C of dissolved total carbonate, and 87Sr/86Sr ratio of aqueous strontium. There are two different types of thermal springs throughout the field, that are chloride-rich water and sulfate-rich water. The chemical composition of chloride springs is controlled by magma degassing and by water-rock interaction processes. Sulfate springs are fed by shallow meteoric water heated by ascending gases. In keeping with the geodynamic setting and nature of the reservoir rocks, chloride water is rich in As, B, Cs, Li; on the other hand, sulfate water is enriched only in B relative to local meteoric water.
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