A case study of compression to escape tectonic transition: Tectonic evolution of the Nallihan Wedge and comparison with the Tercan Wedge (Eastern Mediterranean, Turkey)


Şahin M. , Yaltırak C. , Karacık Z.

JOURNAL OF ASIAN EARTH SCIENCES, cilt.174, ss.311-331, 2019 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 174
  • Basım Tarihi: 2019
  • Doi Numarası: 10.1016/j.jseaes.2018.12.016
  • Dergi Adı: JOURNAL OF ASIAN EARTH SCIENCES
  • Sayfa Sayıları: ss.311-331

Özet

The Nallihan and Carrhan regions in western Anatolia host the stratigraphically and tectonically important features of Nallihan Wedge. The stratigraphic relationships and structural architecture of the wedge are not well understood, which are essential for better understanding of the timing and tectonic evolution of western Anatolia. Today, the Nallihan Wedge is bounded by the North Anatolian Fault and the Thrace-Eskisehir Fault in the northwest and southwest, respectively. The existence of Dagkuplu Melange within the wedge represents the closure of the Izmir-Ankara Ocean. The occurrence of the Lower Jurassic shelf, slope, reef and deep sea successions transitioning upward into the Cretaceous shelf and slope successions represent the opening and closing cycles of the Intra-Pontide Ocean. The tight and asymmetric folds (steep in the west, gentle in the east) within this stratigraphic sequence and the development of the Eocene units reflect the closure of the Intra-Pontide and izmir-Ankara oceans. The geometric structure and evolution of the Nallihan Wedge is directly related to the final continental collision. W-E and SW-NE striking large-scale oblique thrusts also exhibit notable strike-slip components within the study area. The principal direction of the fold axes are W-E and WNW-ESE oriented for the Eocene and Neogene units. During the Eocene, the depositional environment of the study area was a ramp basin mainly dominated by a braided river, when a portion of the Intra-Pontide Ocean was situated on the northern side of the study area. The compressional tectonic regime continued to the end of the Oligocene, which is followed by a new tectonic regime during the Miocene, when the triangular shape region between the Thrace Eskisehir Fault and the North Anatolian Fault developed as an intermontane basin. The evolution of this basin can be compared with the Tercan Wedge, bordered by the North Eastern Anatolian Fault and the North Anatolian Fault.