| Title | Tectonic Setting and Hydrogeochemical Properties of the Geothermal System of Kula Volcanic Region, Western Anatolia, Turkey |
|---|---|
| Authors | Hasan SÖZBİLİR, Alper BABA, Bayram KOCA, Neslihan KİRAY, Murat KARAŞ |
| Year | 2020 |
| Conference | World Geothermal Congress |
| Keywords | Kula volcanic field, Gediz Graben, Geothermal Systems, Turkey |
| Abstract | Kula volcanic Region is represented by young basaltic outcrops of mantle origin in the northern horst of the Gediz Graben. Kula is located on a block of crystalline rocks of the Menderes Massif which is delimited by a southward-tilted footwall block of the Simav Graben or a southward-tilted hanging-wall block of the Alaşehir graben. Menderes Massif has formed the basement of the study area and composed of gneisses and various schist with marble interlayers. The ophiolitic is outcrops in a small-scale, tectonically overlie the basement rocks. The Vezirler Mélange is overlain unconformably by a 700 to 1000 m thick Neogene-Quaternary volcano-sedimentary sequence. Basaltic volcanism, which is composed of basaltic lava and pyroclastic material, developed in the Quaternary period and spread over large areas. Field-based structural study together with remote sensing methods has been applied to the Kula Volcanic field. Our studies suggest that the Kula volcano was emplaced within a releasing bend of NE-SW trending strike-slip fault which is established in the present study for the first time and named as Kula Fault. Kula fault is accepted a crustal-scale zone of weakness was formed oblique to the direction of N-S extension during Quaternary time. The geothermal fluid of the region is mainly tectonically controlled by these types of faults and is seen in the intersection of them with the NW-SE trending normal faults. Different alterations have been observed along these fault zones and thermal springs appeared on the surface at these points. Hydrogeochemical data show that the fluids of the study area comes from the same reservoir and recharge from the meteoric origin. Water samples from Kula can be classified as sodium bicarbonate (Na-HCO3) type water. The geothermal wells have similar chemistry and thus a likely similar source. Kula geothermal water plots in the immature range compared to thermal waters worldwide. Stable isotopic composition of Kula waters generally falls along the meteoric mixing line. The isotopic composition of the waters suggests that recharge to the geothermal system is precipitation. Geothermal springs appear to be fed by a mixture of thermal water and groundwater resources. Cation geothermometers data indicate that the reservoir temperatures of the fluid are range from 80-142 OC in the study area. |