A Lower Pleistocene to Holocene terrestrial record from the Eskisehir Graben (Central Anatolia): Paleoclimatic and morphotectonic implications


OCAKOĞLU F. , AKKİRAZ M. S.

QUATERNARY INTERNATIONAL, vol.510, pp.88-99, 2019 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 510
  • Publication Date: 2019
  • Doi Number: 10.1016/j.quaint.2018.12.026
  • Title of Journal : QUATERNARY INTERNATIONAL
  • Page Numbers: pp.88-99

Abstract

As one of the rare terrestrial archive with continuous sedimentation back to almost 1 Ma in Anatolia, the Eskisehir Graben was investigated in outcrops and cores by multi-proxy analysis regarding chronology and paleoclimatology. The present study comprises significant implications for both the impact of climate changes on fluvial systems in the timescales of the Milankovitch band and the controversial age and rate of the crustal extension in western Anatolia. Our findings indicate that LOI950 and delta O-18(carb), which are indicators for the amount of soil carbonate and paleo-temperature respectively are collectively capable of distinguishing between glacial and interglacial periods in the predominantly floodplain deposits of the graben infill. Secondarily, LOI550 and delta C-13(carb) values further help this discrimination via primary production and composition of vegetation cover respectively. Pollen data, albeit highly discontinuous due to poor preservation under subaerial conditions, point out a steppe-like vegetation cover where the forest components expand particularly in the wet interglacial periods. In the other hand, the chronological frame provided by astronomical calibration of certain proxy-records strongly suggest that the Eskisehir Fault Zone initiated as a boundary fault of a half-graben some 900 ka. The rate of vertical movement on its southern branch since the last 70 ka is unexpectedly high (2.3 mm a), a phenomenon that requires urgent risk assessment analysis in the vicinity of the Eskisehir city.