Structural Evidence For Extensional Domain-Type Geothermal Play In Western Anatolia: A Case Study From Afyon-Akşehir Graben

Abstract

Afyon-Akşehir Graben (AAG) which consists of the southeastern part of Akşehir-Simav Fault System (ASFS) is one of the active depression areas in Western Anatolia. The western sector of the NW-SEtrending AAG is controlled by many active normal fault segments, namely Erkmen, Gecek, and Gazlıgöl Faults. Two main geothermal fields namely, Ömer-Gecek and Gazlıgöl contain reservoirs of fluid with temperatures up to 130° C, are located on the junction points of Gecek-Erkmen faults and Gazlıgöl-Yarımca faults, respectively. The area contains three unconformity bounded geological units; Mesozoic rocks of the Afyon Metamorphic Zone (reservoir unit), Miocene volcano-sedimentary succession (cover unit), including several sedimentary and volcanic units and Quaternary modern basin-fills of alluvial, fluvial and travertine deposits. This study involves use of geological mapping and structural geology methods to identify play type of geothermal fields mentioned above. Paleostress inversion analysis based on basin-bounding active faults and active extensional cracks along the travertine deposits shows that the AAG has been deformed under the control of multidirectional extension, with E-W and NE-SW to NW-SE orientations since Plio-Quaternary time. These types of extension are directly related with the linkage of cross faults that oriented at high-angle to the strike of NW-SE-trending major breakaway fault of AAG. Field-based studies also reveals that geothermal fields in AAG develops on the interactions of these active faults on the extensional domain type geothermal play without active volcanism coming to the surface.

Bolvadin Asismik Yüzey Deformasyonlarının Yerleşim Alanlarına Etkilerinin İncelenmesi

“…Batı Anadolu Genişleme Bölgesi içerisinde yer alan ve bu bölgedeki en önemli sismojenik kuşaklardan birisi olan çerisinde KB-GD gidişli çok sayıda aktif fay zonları bulunmaktadır. ASFS, doğuda Ilgın, batıda ise Bigadiç ile sınırlandırılan yaklaşık 400 km uzunluğunda, KB-GD uzanımlı neotektonik bir yapıdır (Koçyiğit, 1984;Koçyigit and Özacar 2003;Koçyigit and Deveci 2007;Emre vd., 2011;Gürboğa, 2013;Özkaymak vd., 2017;2020). Sistemin batısı Simav Fay Sistemi (SFS), doğusu ise AAG olarak isimlendirilmektedir.…”