Geological features of Kışla dome structure in South of Isparta and its tectonic evolution, SW Turkey

Geographic structure named as Isparta Angle in SW Turkey is generated by the folding of carbonate axis in terms of opposite “v” forming Western Taurides in the northern part of the Antalya Gulf. The Mesozoic rocks in the western part of the Isparta Angle form the Beydağları Platform. Besides, the Akseki-Anamas Carbonate Platform forms the eastern side of the Isparta Angle. The rocks in the southern part of the Isparta Angle and in environment of Antalya are composed of allochthonous ophiolithic components and can be considered as Antalya Nappe. On the other side, the allochthonous rocks as Lycian Nappes with ophiolithic components overlie the western part of the Isparta Angle. Moreover, the allochthonous rocks known as Beyşehir-Hoyran and Bozkır Nappes overthrust the eastern part of the Isparta Angle and form the most important nappe system in the area.
   Satellite imageries of the area located 20 km south of Isparta indicate a circular dome structure around Kışla. This dome structure has been generated within the Isparta Çayı Formation and the overlying marine clastic series in Antalya Nappes. The radius of this circular dome structure reaches up to 10 km approximately. Two and three dimensional satellite imageries of the study area, the map of tectonic lineaments and the map of surface temperatures prepared using thermal band of satellite imageries (Landsat ETM+) support the existence of a dome structure in the study area.
   The rocks in the investigated area can be divided into two groups within a geological map of scale in 1:25000: (i) autochthonous-paraautochthonous and (ii) allochthonous rocks. The autochthonous-paraautochthonous rocks in the area consist of Davraz Formation (Early- Late Jurassic carbonate rocks), Beydağları Formation (Early-Late Cretaceous carbonate rocks), Yazır Limestone (Aquitanian reef limestone) and Ağlasun Formation (Burdigalian flysch). The allochthonous rocks in the region are composed of rock components formingAntalya and Yavuz nappes. Antalya Nappes are represented by Isparta Çay Formation (Early-Middle Triassic stratified chert and plaquette limestone) and rocks in ophiolite melange. In the region, the rock units in Antalya Nappes overlie the carbonate rocks of Beydağları Formation in the southern part of the investigated area tectonically. Besides, the Eocene turbidites known as Yavuz Nappes, form the other important allochthonous unit in the region. The Eocene units belonging to Yavuz Nappes and overlie the Miocene (Aquitanian to Burdigalian) units tectonically.
   On the other side, the dikes and subvolcanic domes of trachytic (5,45 ± 0,21 – 5,77 ± 0,22 Ma) and lamproitic (6,75 ± 0,25) composition are located in various points of the study area. These volcanic formations are located in Antalya-Isparta volcanic belt of N-S strike mostly. By a tectonical interpretation of the investigated area, the area was affected by two various compressional tectonic forces, namely N-S and E-W. The time interval from Late Cretaceous to Early Pliocene contains compressional tectonic features in N-S direction dominantly. After Early Pliocene time, the area was affected by compressional tectonic features in E-W direction. These compressional tectonic features affecting the study area and developing after each other and in various directions are the tectonical reasons which led to the formation of the Kışla Dome. On the other side, subvolcanic dikes and domes in the Kışla Dome area reflect a magmatic activity in the same age with the Kışla Dome which is supported by age determinations of volcanic rocks and their equivalent plutonic rocks such as syenite xenolithes (trachyte: 5,77 ± 0.22 Ma and 24.000 ± 2.000 a; Syenite: 4,92 ± 0,9 Ma).