Post miocene deformation of the area between Alibey (Kızılcahamam) and Karalar (Kazan) villages, nw Ankara (Turkey)


Thesis Type: Postgraduate

Institution Of The Thesis: Middle East Technical University, Faculty of Engineering, Department of Geological Engineering, Turkey

Approval Date: 2004

Thesis Language: English

Student: Aykut Karaca

Consultant: FUAT BORA ROJAY

Abstract:

The study area is located within the Neogene-Quaternary sequences on top of the Mesozoic accreted mass at the northwest of Kazan (40 km NW of Ankara) between Karalar and Alibey villages. The research deals with the post-Miocene deformational history of an area situated at the southern edge of Galatian Volcanic Province. Two main Neogene rock sequences are cropped out; 1) Late Miocene Pazar Formation, 2) Plio-Quaternary Sinap Formation. The Pazar Formation has a succession composed mainly of clastics at the bottom and, cherts and limestones to the top of the sequence representing a fresh water lake environment. Sedimentation seems to be affected by the intense volcanism going on in the Galatian Volcanic Province. Location of a mammalian fossil found in the Pazar Formation yielded a possible time interval between MN-9 to MN-13 (Middle to Late Miocene). Sinap Formation overlies the Pazar Formation unconformably and it is dominantly represented by fluvial clastics. The post-Miocene deformational studies based on the analysis of the structural data collected from bedding planes and fault planes. Totally 213 dip-strike measurements from the Neogene units and 204 slip lineation data from the fault planes were taken. Fold analysis of dip and strike measurements taken from the Pazar Formation gave a common fold axis trending in N430E direction. Similarly fold analysis for the Sinap Formation resulted N400E striking trend for the fold axis. Stress analysis was performed by processing slip lineation data using Angelier direct inversion method. In the analysis, no reliable results for the post-Miocene compressional phase could be obtained. But the results of the post-Plio-Quaternary extensional regime are strongly reliable. It clearly gives an extension in NW-SE direction. Stress analysis together with the field observations show that the area has been structurally evolved in