Post-Collisional Deformation of the Anatolian Orogeny, Turkey: Insights from Geochronology and Sedimentology of the Saricakaya Basin, Western Anatolia

Anatolia is a complex mosaic of terranes that collided from the late Cretaceous through the Paleogene. In western Anatolia, the most significant collision occurred between the Sakarya Zone of the Pontide terrane and the Tavsanli Zone of the Tauride-Anatolide Platform. At least 700 km convergence since 90 Ma was facilitated by the subduction zone(s), today marked by the >1700 km long Izmir-Ankara-Erzincan suture. Despite the large volume of work on the numerous Anatolian terranes and collisions, basic questions regarding the onset of subduction, number and polarity of subduction zones, timing of collision, style of post-collisional deformation, and development of topography and fold and thrust belts remain enigmatic.

Here, we discuss early fold-and-thrust belt development of the western Anatolian orogeny through the stratigraphic and sedimentologic evolution of the Saricakaya Basin. This basin is a small, poorly-studied sedimentary basin between the Izmir-Ankara Erzincan suture zone and basement-involved Söğüt Thrust fault, and exposes a thick, Paleocene(?)-Eocene sedimentary sequence thrusted by post-collisional orogenic build-up. New age constraints from zircon U-Pb dating of volcanic deposits, and new data from U-Pb detrital zircon geochronology and sedimentary facies reveal changes in provenance and depositional environments related to the post-collisional evolution of the suture zone. We show that the Saricakaya Basin is a Paleocene(?)-Eocene post-collisional wedge-top basin created by loading from the Söğüt Thrust, and the depositional environments record periods of thrust building and quiescence. Unlike the thin-skinned fold-and-thrust belt of central Anatolia, the Saricakaya Basin documents an along-strike change in deformation style and orogenic evolution.