TECTONIC DEVELOPMENT OF THE ANKARA-ERZINCAN SUTURE AND THE EASTERN
PONTIDE MOUNTAINS, NORTHEAST ANATOLIA, TURKEY
Abstract
The Eastern Pontides are the northmost component of the Anatolian
orogen. Its geological development closely associated with the evolution
of the Ankara-Erzincan Suture. It exhibits records of the events from
the opening to the eliminations of the surrounding oceans. During the
Late Paleozoic, the Pontides were located in the north of Gondwana,
facing the Paleo-Tethys Ocean. The southward subduction of the Paleo
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
located between the Pontides, and the Taurus was closed under the
northerly advancing Taurus nappes during the Late Eocene. The latest
collision is related with 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 the 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.