The assessment of the hydrothermal alteration data of the Balçova geothermal field

The studied area, Balçova Geothermal Field, is located 10 km western part of zmir. The lithology in the field, from oldest to youngest, are the Upper Cretaceous zmir Flysch, Miocene aged Yeniköy Formation, Pliocene aged Cumaovası Volcanites, Quaternernary alluvium and debris flows. Balçova Geothermal Field is a very important field in our country and has been studied by many researchers and scientists. All these studies have also guided this thesis. By examining the structural, hydrogeological, geochemical properties of the Balçova Geothermal Field, relationship between these and geothermal potential of the field has been searched. Hot water samples have been taken from the deep wells present in the Balçova Geothermal Field. The analysis of the samples have been run in the computer program named ?Aquachem 3.70? and classified by the diagrams obtained. After examining the well-logs of several deep wells, cutting samples and well-cores have been taken from the appropriate levels and studied by the means of petrology and hydrothermal alteration. As a result; 3 zones have been determined in the field. These are; montmorillonite + kaolinite zone (100-200°C), transition zone (150-200°C) and chlorite + illite zone (200-250°C), matching with the former shallow well alteration studies. By applying chemical geothermometers to the samples, maximum 240°C of a temperature is obtained. From the hydro-isotherm map of the field, drawn by correlating the whole data, possible geothermal boundary, possible maximum temperature and extension of the geothermal field have been interpreted.