Volcano Stratigraphic Investigation of the Post-Collisional Middle Eocene Magmatism Around Izmir-Ankara-Erzincan Suture Zone (NE, Turkey)

Abstract

The obliteration of the Neo-Tethyan Ocean along the northern part of Turkey leads the development of the Izmir-Ankara-Erzincan suture zone (IAESZ). After the suturing stage; extension and magmatism concomitantly developed on the both sides and along the IAESZ during the middle Eocene. During this stage, the areas confining to Almus, Yildizeli, and Yildizdag regions have experienced a severe magmatic activity. Middle Eocene magmatism in Almus and Yildizeli areas are represented by the volcano-sedimentary successions. Besides, in Yildizdag region, gabbroic and dioritic intrusives are the dominant manifestations of magmatism. The volcano-sedimentary successions from Almus and Yildizeli areas represented by shallow marine sedimentary units at the lower parts and lava flows and volcanoclastic units at the middle to upper parts. Eight volcano-sedimentary sections from Almus and Yildizeli measured to demonstrate the evolution of the magmatic units developed coevally along the both sides of the suture zone. In both regions; three different volcanic episodes are differentiated based on stratigraphy. First episode includes amphibole-basaltic andesite, andesite, and dacite. Second episode contains basalt and pyroxene-basaltic andesite lavas and third episode represented by trachyte and trachyandesite dikes and stocks. The field data from the all regions demonstrated that middle Eocene magmatic units along the post-collision zone concominantly developed in a wide area and triggering of the magmatism controlled by the region-scale delamination and/or lithospheric removal processes.