부산대학교 도서관

Using optically stimulated luminescence (OSL) dating, the deposits of the crest (ridge) landforms in the Tobol–Ishim interfluve (southwestern part of the West Siberian Plain), foot slope colluvial deposits on the right-bank terrace of the Ishim River valley and the dune sands in the Tobol River valley and its tributaries have been studied for the first time. The OSL ages obtained for the first time indicate older ages of crest deposits, than previously assumed, from 33.5 ± 1.5 to 25.8 ± 1.3 ka. The formation of the foot slope colluvial cover on the right bank of the Ishim River valley began ~22 ± 2.0 ka ago. Dune pine forest sands in the Tobol River valley relate to the later stage of aeolian accumulation and were formed due to secondary wind reworking of the alluvial sediments of the first terrace above the floodplain in the Late Glacial–Holocene. The uniformity of depositional conditions over the entire area of the crest relief in the study territory is revealed. [ABSTRACT FROM AUTHOR]