Investigation of the deep geothermal structure of the southwest section of Bolvadin (Afyonkarahisar)

In this study, it is aimed to investigate geothermal energy potential of the southwestern part of Bolvadin with geological and geophysical methods. Paleozoic aged Paşadağ limestones and calchschist and quartzite type rocks observed in Doğanlar schist are also reservoir rocks for the geothermal system. Doğanlar schists have the characteristics of an alluvial cover rock with an impermeable basement and clay-rich layers of the Gebeceler formation. Bolvadin study area is tectonically located within the Afyon-Akşehir Graben (AAG) and is under the influence of the edge faults of the graben. Considering the geological structure of the project area, magnetotelluric (MT) data were collected at 75 stations and Direct Current Resistivity (DDA) data at 10 stations along the NW-SE directional measurement profiles. The results of geophysical and geological observations were evaluated together and the shallow and deep geothermal structure of the region was revealed. According to MT models; In the project area, low resistivity (<20 ohm.m) levels reflecting impermeable cover rock in the Northwest-Southeast oriented profiles exhibit a thinner appearance in the NW sections of the profiles, while the cover thickness increases towards SE. The high resistivity levels (>100 ohm.m) reflecting the upper levels of the metamorphic rocks and the high resistivity levels (>100 ohm.m) representing the impermeable foundation of the geothermal system also deepen from the northwest to the southeast of the study area in accordance with the cover levels. In addition, the low resistivity (<10 ohm.m) levels determined from a depth of 1.5 km from the surface have been interpreted as the possible heat chamber of the geothermal system.