Development history and composition of peatland in the Numto natural park in Western Siberia, Russia

Abstract

A flat frost mound bog in the Numto Natural Park located in the northern taiga of Western Siberia (Khanty-Mansi Autonomous Okrug) was studied. Radiocarbon dating showed that the peatland formation began about 6658 cal years BP. Peat accumulation was slow due to the permafrost influence. The peat accumulation rate had the highest value of 0.3 mm/year between 5500 and 3400 cal years BP, then it sharply decreased to 0.1 mm/year due to climate cooling and remained at that level up to day. The change from cotton grass to sphagnum peat, which indicated transition to the oligotrophic stage of peatland development, was dated around 1800 cal years BP. The chemical composition of peat was characterized by the increase in Cu, Ni, Zn, Mn, Li, Ti and Mo concentrations with depth. The peak of Pb concentration in the upper horizon was likely to result from the former technogenic impact. Concentrations of microelements in the studied peat core were generally comparable to those in peatlands in the south-east of Western Siberia, except for the high concentration of Zn that was connected with the predominance of cotton grass in the major part of the studied core.