OSL Dating of Fluvial Strath and Delta Terrace Levels of the Kızılırmak River: Implications for the Uplift of the Central Pontides
Abstract
The Central Pontides is an actively deforming and uplifting mountain range located at the northern margin of the Central Anatolian Plateau (CAP). The Kızılırmak River traverses the Central Pontides and forms deep bedrock gorges, strath terraces and a large delta in the Sinop Graben of the Black Sea. The presence of strath terraces and uplifted paleo-delta levels along the lower course of the river indicates a response of the Kızılırmak River to rock uplift in the Central Pontides and sea-level fluctuations in the Black Sea. To understand the tectonic and climatic interactions along the river course we employed geologic and geomorphic mapping and implemented optically stimulated luminescence dating (OSL) methods. Our study reveals several levels of strath- and paleo-delta terrace levels that range from 10 m to 180 m above mean river and recent delta level (amrl and ardl, respectively). We collected OSL samples from 11 locations corresponding to 10 strath and delta terrace levels where suitable deposits are exposed. Paleo-terrace levels exist up to the high plateau of the Central Pontides. Our results indicate a Quaternary regional uplift in the eastern part of the Central Pontides. The uplift rates vary between 0.07 and 0.35 m/ka, which indicates a complicated activity of the tectonic pattern in time and space, due to the interaction between the positive flower structure of the North Anatolian Fault Zone and the rifting of the Sinop Graben. The delta terraces on the western side of Kızılırmak River are uplifting faster than on the eastern side. On the other hand the southern part of the delta terraces is uplifting slightly faster (0.12 m/ka and 0.31 m/ka, respectively) than the northern part (0.07 m/ka and 0.17 m/ka, respectively) since Middle Pleistocene (ca. 420 ka). An accelerated uplift rate of 0.35 m/ka south of the Alaçam segment of the Erikli Fault compared to its north (between 0.07 and 0.17 m/ka) indicates an activity since ca. 300 ka. The lowermost terrace level with a height of 7 to 10 m amrl might correspond to the Bølling-Allerød interstadial and implies a Black Sea sea level highstand some meters higher than recent.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFMEP11B1008B
- Keywords:
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- 1130 Geomorphological geochronology;
- GEOCHRONOLOGYDE: 8040 Remote sensing;
- STRUCTURAL GEOLOGYDE: 8107 Continental neotectonics;
- TECTONOPHYSICSDE: 8175 Tectonics and landscape evolution;
- TECTONOPHYSICS