Paleoglacial records from Kavron Valley, NE Turkey: Field and cosmogenic exposure dating evidence

摘要

Kavron Valley lies in the Kackar Mountain range of northeastern Anatolia and is a north-south-oriented, typically U-shaped glacial valley consisting of a main and three tributary valleys. The Quaternary units that outcrop in this valley have been mapped and 22 samples have been processed for surface exposure dating using cosmogenic ~(10)Be. According to the ~(10)Be ages, the advance of the Kavron Paleoglacier began at least 26.0 ± 1.2 kyr ago, with the Last Glacial Maximum (LGM) advance continuing until 18.3 ± 0.9 kyr. After this time the Kavron Paleoglacier receded, although the magnitude of this recession is still unknown. Subsequent to this retreat, the glacier most probably separated into three smaller glaciers that were restricted to the tributary valleys (Ifrit, Derebasi and Mezovit Paleoglaciers). The main valley was definitely ice-free by 15.5 ± 0.7 kyr ago, with the Mezovit Paleoglacier completing its recession around 15.5 ± 0.6kyr. A Late Glacial advance took place around 13.0 ± 0.8 to 11.5 ± 0.8 kyr, and Little Ice Age moraines appear to be absent. Our results from the Kavron Valley system seem to be consistent with the LGM paleoclimate record of Anatolia, which has been delineated by data gathered from lowlands and lakes, the deposition of red clay layers in the northwestern Black Sea and the deposition of Heinrich 1 layers in the North Atlantic.