Hydrochemical and Isotopic Composition of Tuzla Geothermal Field (Canakkale-Turkey) and its Environmental Impacts

Abstract

Tuzla is an active geothermal area located in northwestern Turkey, 80 km south of the city of Canakkale and 5 km from the Aegean Coast. Geothermal brine, deriving from this area, contains an abundance of NaCl and a water temperature of 173°C (T1 well at 814 m depth) is typically encountered. The aim of this study was to determine the hydrogeochemical properties of the geothermal brine using both chemical and isotopic data, and to investigate the origin of the geothermal brine in the Tuzla area and the environmental impacts of Tuzla Geothermal Field (TGF). Both geothermal brine and shallow groundwater in the area are of meteoric origin. Isotope results indicate that the hot saline waters (brine) in the Tuzla geothermal field originate from connate water along faults. As the saline water rises to the surface, it mixes with shallow groundwaters in various ratios. In addition, the high sodium (Na) and chloride (Cl) content in the Tuzla Stream, fed from the Tuzla geothermal brine during the dry season, cause an increase in sodium and chloride concentrations in the shallow groundwaters by infiltration into the aquifer. Moreover, salt accumulation on the surface is observed due to the uncontrolled artesian flow of geothermal brine, which adversely affects the salinity of shallow groundwater.

Keywords:

• Tuzla
• geothermal fluid
• hydrogeochemistry
• oxygen-18
• deuterium
• tritium

Acknowledgments

This study has been funded by the Scientific and Technical Research Council of Turkey (TÜBİTAK) under project number 103Y010. We thank Ibrahim Aksu who checked the English of this article. The authors wish to thank Greg Whitmore for making suggestions to improve the manuscript and the valuable contributions of Serdar Bayari and Tolga Yalcin. Our special thanks to the anonymous reviewers for their help in editing of the manuscript.

Notes

^a Gigenbach (1988),

^b Fournier ve Truesdell (1973),

^c Truesdell (1976),

^d Fourner (1979),

*Calculated by Tarcan, 2005,

**Calculated by Mutlu and Güleç, 1998,

***Calculated by Yalcin, 2007).