First Findings of Buried Late-Glacial Paleosols within the Dune Fields of the Tomsk Priobye Region (SE Western Siberia, Russia)

摘要

Buried soils within aeolian deposits are considered an important tool for diagnosing, determining the age, and estimating the intensity of aeolian processes at the transition from the Pleistocene to the Holocene in the Northern Hemisphere. Late Pleistocene aeolian coversands and ancient inland dunes are widely distributed in the periglacial zone of Western Siberia. In contrast to the territories of Central and Eastern Europe, the paleosol archive of the aeolian sands and dunes of Western Siberia has not yet been studied. This paper presents the first findings of late Pleistocene paleosols within the ancient inland dunes in the southeast of Western Siberia (Ob–Tomsk interfluve, Tomsk region). The soils and their stratigraphic position were studied in the outcrop of the quarry, located in the junction zone of the second Tom river terraces and the ancient valley. Two types of paleosols were identified. The first one is confined to the central part of a small dune and is represented by a slightly developed Albic Arenosol with fragmentary humus horizon Ahb and a well-pronounced Eb. It can probably be considered as an analogue of the European Usselo soil. The second paleosol was found at the bottom of the interdune depression. It is represented by a brown Bwb horizon and probably corresponds to a Brunic Arenosol (Dystric). The second paleosol is characterized by a higher content of clay fraction and organic carbon, the presence of weak signs of illuviation, and richer and more diverse mineral composition. This soil is apparently an analogue of the European Finow soil. Radiocarbon dating of the charcoals found in the paleosols suggests that the first dates from the Younger Dryas (ca. 12,036 cal. yr. BP), and the second one from the Aller?d (ca. 13,355 cal. yr. BP). The study results propose that the natural environment in the periglacial zone of the south of Western Siberia was generally similar to those in Central and Eastern Europe, and the activation of aeolian processes, which led to the formation of a dune relief, occurred at about the same time.