Pim de Klerk Palynology

A pollen diagram from the centre of the Vasyugan watershed mire
(W Siberia), the largest mire in the world

 

The west Siberian lowland, bordered by the Ural in the west and by the Yenisei River and the Central Siberian Plateau in the east, includes ca. 40% of the peatlands worldwide (Tanneberger et al. 2003). Unfortunately, the Holocene vegetation history and mire development of the vast peatlands remains predominantly unknown: scientific research is severely hindered by the inaccessibility of the wetland areas, and therefore concentrates mainly on the easier reachable river valleys. The central areas of the peatlands are palaeoecologically still predominantly unknown territories.

The Vasyugan watershed peatland in the southern part of the West Siberian lowland separates the catchment areas of the Irtysh River and the Ob River and is the largest contiguous peatland worldwide. A helicopter expedition in 2001 enabled access to its southern-central area, which resulted in the retrieval of the 4.27 m long core “VOZ” (Tanneberger et al. 2003). This core was subject to macrofossil and pollen analyses.

The west Siberian lowlands, including the Vasyugan watershed peatland - the largest contiguous peatland worldwide - and location of the analysed core VOZ (*)

The basal part of the analysed section consists of clay which is extremely poor in pollen and macrofossils. This clay layer might have been deposited in a large lake at great distances to its shore. Local terrestrialisation and peat formation - as is indicated by pollen and macrofossils - started with expansion of ferns, sedges, grasses, Equisetum, and Drepanocladus. Afterwards, a bog developed with Sphagna Acutifolia, Sphagna Cuspidata, Sphagnum magellanicum and Ericaceae, whereas trees of birch and pine grew probably also near the cored location ("Ryam").

Radiocarbon dates show that peat formatio at the cored spot started around 4000 cal years BP. Peat accumulation rate remained conspicuously stable up to ca. 500 cal years BP, after which accumulation greatly increased. Sphagnum fuscum, currently the dominant peatforming moss taxon in the west Siberian lowlands, seems to have expanded greatly at the core location only during the last centuries.

Age-Depth relationship of the analysed core “VOZ”

An expedition in the winter of 2003 with armoured vehicles over the frozen mire resulted in the retreaval of several other cores along a 140 km long transect from the peatland margins to the centre (Tanneberger et al. 2003), of which radiocarbon dates are already available. Future palaeoecological research is planned for these cores in order to further elaborate the knowledge on the development of the Vasyugan peatland.

 

This research is carried out in close cooperation with Hans Joosten and Greta Gaudig.

 

Relevant literature:

Tanneberger, F., Hahne, W. & Joosten, J.H.J. (2003): Wohin auch das Auge blicket: Moore, Moorforschung und Moorschutz in Westsibirien. Telma 33: 209-229.

 

 

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