Evaluation of origin of the Ayas-Beypazary geothermal waters with sulfur isotopes, Central Anatolia, Turkey

The aim of this study is to investigate the origin of sulfate in deeply circulating thermal waters around the Ayas-Beypazan region in Turkey. The waters of Ayas, resorts and Coban bath arc of Na-Cl-SO4 hydrochemical fades and waters of Kapullu and Dutlu thermal resorts are represented with Na-SO4-Cl hydrochemical facies. Kirmir Formation gypsum minerals in Mio-Pliocene age have sulfur-34 isotopes between 17 and 25 per mille. According to oxygen-18 (SO4) and sulfur-34 (SO4) contents, sulfate in waters of Ayas and Dutlu resorts and Qoban bath is derived from gypsum of Kirmir Formation of primary source. Sulfates of Kapullu bath water and Karakoca mineral water may be originated from atmospheric and terrestrial environments, respectively. Among the cold groundwaters, sulfate of Tahirler fountain is derived from gypsum in the Kirmir Formation (primary source) and sulfate in Kapullu cold water is originated from a secondary origin (atmospheric). Sakarya River water sulfate is probable originated from atmospheric and terrestrial environments. (author)