Nizina Zachodniosyberyjska – fenomen zatorfień naszej planety
The West Siberian Plain – a curiosity among peatlands of our planet

Summary/Abstract: The largest plain of the Earth (2745 thousand km2) is confined by the Ural Mountains, the Kara Sea, the Yenisei River, and uplands with the Altai Mountains to the south. This slightly concave basin with the Ob and Irtysh River valleys has been covered with peatlands with the area of 760 thousand km2 throughout the last 12 thousand years. In the north, their development was affected by permafrost, in the central part by the prevalence of precipitation over evaporation, and in the south by land relief rich in depressions and lakes. The first expeditions aimed at studies on the peatlands began at the end of the 19th century, and intensified in the 1920’s and 1930’s (Bronzov, Neustadt, Andreev, Gorodkov). After the Second World War, the expeditions were more frequent and numerous. Studies were carried out by the Academy of Sciences (Institute of Forestry, Institute of Geography), universities (Tomsk State University, Moscow State University) and governmental research institutes (State Hydrological Institute in Petersburg, Giprotorfrazviedka). Research was also conducted by individual outstanding scholars such as: Prof. P’âvčenko (tundra peatlands) and Prof. Kac with his wife (pollen analyses, peatland regionalisation). Only in the 21st century two large international field conferences were held concerning comprehensive studies on West Siberia (in Noyabrsk in 2001 and in Khanty-Mansiysk in 2007). Peatland landscapes depend on the climaticvegetation zones. In the tundra, Arctic mineral sedge peatland, polygon-ridges and ice-wedgepalsa develop. The forest-tundra zone includes flat palsa peatlands with a height of up to 1 m. To the south, the northern taiga zone is dominated by high palsa peatlands with a height of up to 11 m, dissected with small inundated hollows. The central, forested part of the West Siberian Plain (46 % of its area) is occupied by the zone of raised bogs with the peatlands cover of up to 40–70%. The convex peat deposits are dominated by thick layers of sphagnum peat fuscum. In the consecutive zone, raised bogs intermingle with transitional bogs and fens in river valleys. Here, between the Ob and Irtysh Rivers, the largest peatland of the World is located – the Great Vasyugan Mire with an area of 5.3 million ha. The southern part of the plain is occupied by the zone of reed, tall-sedge, and saltwater marshes. Small raised bogs called “rjam” rarely rise above them (4 to 6 m higher). Simultaneously with the studies on peat deposits, attempts were taken in order to determine the beginning of peat development on the plain, the peat accumulation rate, and climatic changes that occurred in the Holocene, affecting the development of peatlands. All those issues are discussed in works by S.V. Kac and M.I. Neustadt. The latter distinguished two types of pollen diagrams for the West Siberian Plain already in 1952, namely the forest and forest-steppe type. The author was also the first to date the age of peat by means of the 14C analysis.

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