Tectonic development of the Ankara-Erzincan suture and the Eastern Pontide mountains, Northeast Anatolia, Turkey

Abstract

The Eastern Pontides are the northeasternmost component of the Anatolian orogen. Its geological development is closely associated with the evolution of the Ankara-Erzincan Suture. It exhibits records of the events from the opening to the elimination of the surrounding oceans. During the Late Palaeozoic, the Pontides were located in north of Gondwana, facing the Palaeo-Tethys Ocean. The southward subduction of the Palaeo Tethyan oceanic lithosphere generated an active continental margin and opening of the Neo-Tethys Ocean as a back-arc basin during the Early Mesozoic. Throughout the Jurassic-Early Cretaceous, the Pontides remained a passive continental margin facing the Neo-Tethys in the south. Arc reversal occurred as the Neo-Tethys began subducting under the Pontides during the late Early Cretaceous (?)-Late Cretaceous. The Pontides experienced four collisional events throughout the development of the Ankara-Erzincan Suture; (1)- a forearc-arc collision occurred when the accretionary complex, which formed along the southern edge of the Pontides was backthrust over its leading edge during the Late Campanian. (2)- This was followed by a continent-arc collision when the Kırşehir Massif and the underlying NeoTethyan ophiolite nappe collided with and thrust over the Pontides at the end of the Early Eocene. (3)- Following the oceanic lithosphere’s total demise, the remnant basin survived above the remaining part of the accretionary complex located between the Pontides, and the Taurus was closed under the northerly advancing Taurus nappes during the Late Eocene. The latest collision (4) is the collision of the Arabian Plate with the Anatolian plates. The Arabian Plate’s continuing northward advance after the demise of the NeoTethyan Ocean squeezed and shortened Eastern Anatolia. From this time onward, the Eastern Pontides were thrust to the north and the south over the surrounding tectonic belts and started to rise as a coherent block.