Structural Controls on Gülbahçe Geothermal System and Its Hydrogeochemical Properties (western Turkey)

Abstract

Gülbahçe Geothermal Field (GGF) is located in eastern parts of the Karaburun Peninsula and is about 45 km away from the city of Izmir, Turkey. The stratigraphy around the GGF is represented by a Miocene volcano-sedimentary succession, including several sedimentary and volcanic units. These units overlie the basement rocks of the Karaburun Platform Carbonates and Bornova Flysch Zone which consists of carbonate blocks embedded in sandstone and mudstone alternations. GGF is located on the Gülbahçe Fault Zone, and are composed of series of NW-SE to NE-SW trending faults, extending from Sığacık Bay to Gülbahçe Bay. While most of the geothermal systems in western Turkey are controlled by normal faults, geothermal systems at the Gülbahçe are controlled by NE/NW-trending strike-slip faults and NE/NW-trending oblique-slip normal faults. An association of these active faults accommodating deep circulation of hydrothermal fluids of sea water origin is the primary control mechanisms of geothermal systems of Gülbahçe.