Aydin-soke geothermal area

This area is situated between Germencik geothermal area and Aegean Sea. Hot water springs located northern flank on the main faults of the B. Menderes Graben and north side of the Gumusdag horst.

The temperature range is 20.6–27.5ºC for springs and 41.7ºC for well (Davutlar well). The chemical and isotopic compositions of some 7 water samples have been collected and analyzed from 3 hot water springs, 2 cold water springs, 1 shallow well and 1 sea water.

Main lithologic formations are karstic marble and schists of Paleozoic age. According to hydrogeological studies water samples collected from karstic springs are Ca>Mg>Na+K and HCO₃+CO₃>Cl>SO₄ (Sazlikoy and Priene springs). There is mixing with karstic water and sea water from inland to Aegean Sea and the water composition change to Na+K>Mg>Ca and Cl>SO₄>HCO₃+CO₃ character.

Evaluation of Na-K-Mg diagram is shown in Figure 5. The position of all the data points indicates that the thermal systems of the Soke region are immature waters.

The stable isotope results are given in Table II. Isotopic values of cold waters are very close to MMWL equation δ²H=8xδ¹⁸O+22. Slight deviations from the line shows that, there is an effect of evaporation on cold waters and they originate from shallow circulation and low temperature system (Figure 6 and 7).

The isotopic composition of the thermal waters in the Soke areas shows that they are of meteoric origin. Seawater mixing with this water occurs in the west part of the Soke, particularly near coast.

Seawater flow into the West Soke area is along the main E-W graben fault lines.

4. Results

Hydrogeological and hydrochemical survey have been completed in the project area. Periodical samples have been collected from thermal and cold water points for isotopic and chemical analyses.

The geothermal waters are of meteoric origin and have accumulated their heat during circulation in the fault systems. Only west Soke region shows mixing with seawater.

Evaluation of Na-K-Mg diagram indicates that the geothermal systems of the Kizildere, Germencik and Afyon fields are partially equilibrated fluids.

Deep reservoir temperatures estimated by different chemical geothermometers for two major fields, Kizildere and Germencik are 240–260^oC and 230–260^oC, respectively.

Geothermometer applications have been encouraged for deep reservoir explorations in Kizildere and Germencik geothermal fields. The results of new exploratory wells show that the geothermometer estimates are reliable for Kizildere (242^oC) and Germencik (232^oC) fields.

The geothermal fluids of deep reservoirs in Kizildere and Germencik fields are low acidic character as pH: 5.5–5.9 and pH: 4.9–5.5 respectively.

The absence of tritium in Kizildere, Germencik and Afyon geothermal waters indicates that residence time of recharging water in the geothermal system is more than 50 years while at the Soke region thermal waters appear to be young in age. According to the result of ¹⁴C contents, thermal waters have a relatively age of 10000 to 30000 a.

There are clear δ¹⁸O shift from MMWL in Kizildere and Germencik high temperature fields. Also good relation with high temperature and δ¹⁸O shift are determined. It shows deep circulation and water-rock interactions. There are slight δ¹⁸O shift in Afyon fields. But, in Soke region low temperature, low shift, shallow circulation and mixing with shallow cold water and seawater are observed.

According to results, the fields are important for geothermal development and utilization in Denizli-Kizildere and Germencik for generation of electricity, central heating CO₂ production balneological and Afyon-Omer, Gecek geothermal fields for central heating and balneological point of view.

Using isotope technology methods in the geothermal fields of Western Anatolia provided a very useful tool in developing the hydrogeological model of the area. Improvement of the laboratories of the agency as to be able to analyze other isotope contents of both water and gas would contribute to much to the research project that will be implemented in the future.

Acknowledgements

This study has been carried out within the framework of the IAEA Coordinated Research Program.

“The Use of Isotope Techniques in Problems Related to Geothermal Exploitation “(Research Contract No 9829/RO-R1). Sincere thanks to staff members of Isotope Hydrology Section of the IAEA. The authors are deeply thank Prof. Dr. GUNAY (Director of UKAM) for his support made this work successful. The authors are grateful M. S. DOGDU and B. AKAN from UKAM and to Mr. N.

YILDIRIM from MTA for his assistance and scientific advance during the sampling and evaluation of data. The authors express their appreciation to N. TURKMEN from TEAS (Turkish Electricity Authority Manager of Kizildere Geothermal Power Plant). I also thank E. ONCEL and F. MUSLU for chemical analyses and B. TOPUZ for office works.

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CHEMISTRY OF NEUTRAL AND ACID PRODUCTION FLUIDS FROM THE