Geology and Hydrogeochemistry of Gure (Balikesir) Geothermal Field and its Relationship with Active Tectonic

Kacar B., ÖZDEN S. , ATEŞ Ö.

TURKIYE JEOLOJI BULTENI-GEOLOGICAL BULLETIN OF TURKEY, vol.60, no.2, pp.243-258, 2017 (Journal Indexed in ESCI) identifier

  • Publication Type: Article / Article
  • Volume: 60 Issue: 2
  • Publication Date: 2017
  • Page Numbers: pp.243-258
  • Keywords: Active Fault, Earthquake, Geothermal, Gare, Hydrogeochemisty


Gure geothermal field is located in NW Anatolia within the boundaries of Balikesir. This study attempts to determine the geologic and hydrogeochemical characteristics of the field and close surroundings and their correlation with active tectonism. The basement of Gure geothermal field is rocks of the Paleozoic-age Kazdag Group. Above the basement, the Triassic-age Karakaya Formation lies above an unconformity. The Cretaceous cetmi melange tectonically overlies this basement. The Upper Oligocene-Lower Miocene Hallaclar volcanics and Oligo-Miocene granodiorites were emplaced by cutting all older units. Quaternary alluvium unconformably overlies all units in the study area. The Gure geothermal field located on the east section of the Edremit Fault Zone, marked as an active fault on the Active Fault Map of Turkey, is controlled by a nearly ENE-WSW oriented, south-dipping normal fault. In the instrumental period from September 2013 to August 2014, nearly 12 earthquakes occurred in this region and close surroundings with M=3.0 or more. Geothermal water from four hot-water wells in the Gure goethermal field had monitoring studies performed in 12 different periods, from 21.09.2013-16.08.2014. Physicochemical measurements and experimental studies of water from Gure geothermal field were compared simultaneous to earthquakes in the region. Before and after earthquakes changes were observed in these thermal waters, especially 7 degrees C, pH and EC values. Additionally chemical analysis of the water identified increases or reductions in many elemental levels, especially Cl, Na+ and SO4-2. It was concluded that these variations were directly related to the active tectonic regime in the region.