An Update of the Geothermal Potential in the Continental Rift Zone of the Büyük Menderes, Western Anatolia, Turkey

Abstract

In Turkey, the eastern Mediterranean area between the Eurasian and African plates is controlled by the Anatolian and Aegean microplates tectonically. This plate tectonic evolution results in the uplift of the Menderes Massif which shows a dome shaped structure due to compressional tectonic features through Oligocene and Miocene. During Early to Middle Miocene, the continental rift zones of the Büyük Menderes, Küçük Menderes and Gediz were formed by extensional tectonic features striking E-W generally and representing a great number of active geothermal systems, epithermal mineralizations and volacnic rocks from Middle Miocene to recent. The thermal waters are associated with the faults which strike preferentially NW-SE and NE-SW and locate diagonal to general strike of the rift zones of the Menderes Massif. These NW-SE and NE-SW striking faults were probably genarated by compressional tectonic regimes which leads to the deformation of uplift between two extensional rift zones in the Menderes Massif. In addition to heat flow anomalies in the rift zone of the Büyük Menderes, there is very intensively volcanic activity which is represented by various localities of a great number of calcalkaline towards acidic volcanic rocks and ranges from Middle Miocene to 18.000 a in age. The volcanic rocks are of products of continental crust based on isotope analyses of 87Sr/86Sr and 144Nd/143Nd and can be considered as heat source fort he heating of the thermal waters in the rift zone of the Büyük Menderes and elsewhere. Additionally, the geothermal gradients may contribute to heat the thermal waters in the reservoir consisting of limestones, marbles, quartzites and gneisses. One of these continental rift zones is the rýft zone of the Büyük Menderes. The good investigated thermal waters of Kýzýldere, Salavatlý and Germencik located in the continental rift zone of the Büyük Menderes represent typical examples of active geothermal systems and advise to indicate a big potential up to 600 MW (Kýzýldere: 150 MW; Salavatlý: 150 MW; Germencik: 300 MW) in the area for future.