TY  - JOUR
TI  - Multiple fluid-mineral equilibria approach to constrain the evolution of thermal waters
in the Hisaralan geothermal field, Simav Graben, western Turkey
AB  - In this study seasonal changes in the geochemical and stable isotope compositions of Hisaralan thermal waters in Simav
Graben, western Turkey, were investigated with regards to a variety of mineral-water interactions and mixing processes. The Hisaralan
and Emendere geothermal waters, with temperatures of up to 99 °C, were mostly of Na-HCO3
 and Ca-HCO3
 types. The δ18O and δ2
H
values of the Hisaralan waters ranged from –9.32‰ to –8.73‰ and –65.02‰ to –61.10‰, with maximum seasonal differences of 0.3‰
and 1.8‰. The Emendere waters were represented by a more positive range of δ2
H values (–54.95‰ to –54.61‰), while their δ18O
compositions (–9.04 to –8.41‰) were very similar to those of the Hisaralan waters. The stable isotope compositions of the Hisaralan
thermal waters were consistent with those of the global meteoric water line, whereas the Emendere waters closely resembled those of
the Marmara meteoric water line. The δ13C of the dissolved inorganic carbon varied from –4.33‰ to –2.77‰ for the thermal waters
and from –13.84‰ to –12.51‰ for the cold waters. These values indicated a marine carbonate origin for the former and an organic
source for the latter. Sulfur isotope systematics of dissolved sulfate in the Hisaralan geothermal waters indicated that the sulfate was most
likely derived from the dissolution of marine carbonates and terrestrial evaporites. Chemical geothermometers applied to the Hisaralan
thermal waters yielded average reservoir temperatures of 123 to 152 °C, which were rather consistent with those estimated using the
silica-enthalpy (146 to 154 °C) and chloride-enthalpy (142 to 178 °C) mixing models. The recharge elevations of the thermal waters that
were computed from the δ2
H compositions were between 1060 and 1330 m.
AU  - Mutlu, Halim
AU  - Yüksel, Ali Kamil
AU  - Gokgoz, Ali
AU  - Özkul, Mehmet
DO  - 10.3906/yer-2007-14
PY  - 2021
JO  - Turkish Journal of Earth Sciences
VL  - 30
IS  - 2
SN  - 1300-0985
SP  - 182
EP  - 203
DB  - TRDizin
UR  - http://search/yayin/detay/521446
ER  -