Structural controls on Kızıldere geothermal field, Denizli-Turkey

Aksu, Baykan
Kızıldere geothermal field is one of the hottest fields located in south-western Anatolia and electricity has been produced from geothermal source since 1984. This high enthalpy geothermal field is located at the eastern edge of Büyük Menderes graben, which is one of the most active extensional structure belonging to the western Anatolian graben-horst system. Büyük Menderes graben, which hosts numerous geothermal fields, is a 3 - 30 km wide, 170 km long, nearly E-W trending depression developed under the N-S directed crustal strain. The study area includes four different continental sedimentary packages separated by regional unconformities. Play type of Kızıldere geothermal field is developed within an extensional domain where heat is supplied by the percolation of cold meteoric water that heated up at depth and recharges the system. In order to identify structural control of this field, geological mapping and characterization of the faults were performed. Three types of faults, which played a role on the geothermal system were identified. These are approximately E-W striking high angle normal faults, N-S striking subvertical faults and a low angle old detachment fault developed possibly prior to the development of preceding faults. In order to understand the geology and geometry of the system, in addition to field data, 76 well-data were used to develop the 3D solid model of the Kızıldere geothermal field. Interpretations of these data showed that the intersections of N-S trending subvertical transfer faults with the E-W striking normal faults played an important role in the development of the geothermal system present in the Kızıldere geothermal field.