Mahmudiye-Çifteler-Emirdağ (Eskişehir güney doğusu) havzasının neotektoniği
Özet
The İnönü-Eskişehir Fault Zone is a WNW?ESE striking right-lateral strike-slip deformational area with a normal component that extends from Uludağ in the west to Sivrihisar in the east and separates the western Anatolia region from the central Anatolia in the northeast. This fault system consists of E?W- and NW?SE-trending fault sets and segments which have potential to produce earthquakes. The İnönü-Eskişehir Fault System is composed of Eskişehir, Alpu, Orhaniye, Günyüzü, Ilıcabaşı and Cihanbeyli Fault Zones in an area extending from İnönü to the west, to the south of the Salt Lake to the southeast.The fault zones experienced the investigated area are Eskişehir, Alpu and Orhaniye Fault Zones. The Eskişehir Fault Zone is consisted of right lateral strike-slip fault segments with normal component in N30W trend extending from Yörükkaracaören village in the west to the west of Sivrihisar town to the east. These segments are Yörükkaracaören, Bardakçı-Kaymaz and Paşakadın fault segments. The Alpu Fault Zone includes strike-slip fault segments striking in EW, NE and NW trends. As for he Orhaniye Fault Zone is constituted of oblique normal faults with right-lateral strike-slip components controlling the southwestern boundary of the Mahmudiye-Çifteler-Emirdağ basin. These fault zones, which are presumably active since Pliocene, have produced earthquakes in medium magnitudes in the instrumental recording period (e.g., M= 6.4, 1956).The Mahmudiye-Çifteler basin is a fault-controlled pull-apart basin in 85 km length and 25 km average width, extending in northwest?southeast trend from Yürükkaracaören village in the North to Emirdağ in the South. The western margins of the basin are marked by a series of oblique-slip normal fault segments in NW?SE trends and the basin is bounded by a basement consisting of Mesozoic marble and schists alternation, ophiolitic mélangé and shallow marine limestones of Early Eocene age. The Upper Miocene limnic limestones unconformably overlaying the basement and outcropping in the middle of the basin, is the first deformed basin-fill unit of the basin. The young and undeformed basinfill or neotectonic unit is composed of terrace conglomerate and sandstones, limnic mudstone and thin limestones of presumably Late Pliocene?Holocene time inwhich the alluvial fan deposits exposing in the western edge of the basin, and the alluvial sediment in the middle of the basin are the youngest basin infills. These two different basinfill and the unconformity between them suggest the superimposed character of the Mahmudiye-Çifteler-Emirdağ pull-apart basin.The strain rate results comprising the last ten years calculated from the TUTGA99 data taken from General Command of Mapping point to a compression in NW-SE trend in the region. Both the instrumentally revealed recent tectonic regime, and the structural data collected from the field show that the investigated area is being experienced by a compressive stress system in neotectonic period.