Hydrogeology and geochemistry in the Curuksu (Denizli) hydrothermal field, western Turkey

Abstract

Curuksu is a low temperature hydrothermal system located within the upper sector of the B. Menderes Graben. The hydrologic structure of the Curuksu hydrothermal system is largely controlled by major graben faults where it is characterized by the presence of two thermal reservoirs. One is formed by Paleozoic quartzite, schist and marble units, and the second consists of Pliocene lime-stone-travertine units. The thermal conditions inthe Curuksu region indicate that the regional tectonics and resulting local stress field control low temperatures activity. Temperatures of 30 springs emerging in the study area range between 15 and55 degrees C. These springs are classified as cold fresh, warm mineral and thermal waters. Pamukkale, Karahayit and Honaz springs are steam condensate waters, whereas Curuksu springs are commonly steam-heated waters with respect to the major anion concentrations. The reservoir temperatures have been estimated from chemical compositions by utilizing simultaneously, geothermometers andmixing models. According to these thermometric methods, the most probable subsurface temperature is in the range of 62-90 degrees C. However, the mixing models suggest a temperature level of 80 degrees C for the parent water. The system has low total dissolved solid (TDS) of similar to 1000-1500 mg/l, which indicate that these waters undergo conductive cooling within the reservoir.