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