A MAGMATIC BELT WITHIN THE NEOTETHYAN SUTURE ZONE AND ITS ROLE IN THETECTONIC EVOLUTION OF NORTHERN TURKEY

The Sakarya and Kirsehir continental fragments of Northern Turkey were separated by the Ankara-Erzincan ophiolitic suture zone, which is the remnant of the northern branch of the Neo-Tethys, namely the Ankara-E rzincan Ocean. This ocean branch opened during the Lias between these two continental fragments and started to close at the beginning of the Late Cretaceous, by the consumption of its floor, along two north-dip ping subduction zones. The northern one was along the southern margin of the Sakarya Continent. As a result of this subduction zone, an ensi alic magmatic are, some fore-are basins and a melange belt developed f rom north to south on the Sakarya Continent. The second subduction zon e, located to the south, gave rise to a melange belt and an island are developed with and on it. Hot-spot magmatics (seamounts), which were scraped from the subducting oceanic crust, also accreted into this oph iolitic-volcanic belt. At the end of the late Cretaceous, the central part of the Ankara-Erzincan Ocean closed due to the collision of the K irsehir and the Sakarya continents. As a result of this collision, mel ange belts and ensimatic are volcanics formed the Ankara-Yozgat suture between these continental fragments.