First experience on optically stimulated luminescence (OSL) dating of the crest relief deposits of the Tobol-Ishim interfluve

Using optically stimulated luminescence dating, the Late Pleistocene-Holocene deposits of the crest relief of the Tobol-Ishim interfluve (southwest of the Western Siberian Plain, Russian Federation), footslope colluvial deposits on the right-bank terrace of the Ishim River valley and dune sands in the Tobol River valley were studied for the first time. The first obtained luminescence ages provide older ages of crest deposits, than previously assumed, from 33.5±1.5 to 25.8±1.3 ka. The formation of the footslope colluvial cover on the right bank of the Ishim River valley began ~22 ka ago. Dune pinery sands in the Tobol River valley relate to a later stage of aeolian accumulation and were formed due to local wind reworking of the alluvial deposits of the youngest river terrace in the Late Glacial-Holocene.