Rotational Evolution of Western Anatolia since the Miocene and Its Implications on the Subduction Dynamics of Eurasia-Africa Collision

The African-European convergent tectonic setting has resulted in a complex deformation history with several large-scale tectonic features in western Anatolia, where is dominated by a crustal-scale extension since the late Eocene. The Menderes metamorphic core complex, the İzmir-Balıkesir Transfer Zone, and the North Anatolian Fault Zone are some of these main tectonic features. To understand their spatio-temporal relationships we employ paleomagnetic, geochronologic and kinematic studies in the northernmost part of the western Anatolia, where these structures interacting with each other. 

Our results show that western Anatolia has experienced at least two separate rotational phases since the Miocene. The first rotational phase is clockwise and related volcanism is dated as 21–16 Ma. The second rotational phase is counterclockwise and related volcanic rocks are dated as 14–12 Ma. According to collected kinematic data, pervasive transcurrent tectonism was dominated during the first phase, while the second one was dominated by extensional (and/or transtensional) tectonism. Here, the mode of extension switched from distributed diffuse deformation to discrete local deformation, possibly due to tearing and retreating of the northward subducting African oceanic slab below the western  Anatolian crust. This interrelated process also led to the localization of the İzmir-Balıkesir Transfer Zone with the decoupling of strike-slip faults, and to the episodic exhumation of the Menderes metamorphic core complex. This study is supported by a Tübitak Project, Grant Number of 117R011.