Research results of the last decades, including numerous radiocarbon dates, confirm that the process of active paludification of the West Siberian Plain started only as late as in the Early Holocene. Field and laboratory research conducted in 1999-2001 showed that climatic conditions prior to the Holocene were not favorable for wetland formation. Peat deposits were studied within three regions, which are different in geological and geomorphological aspects: (1) the northern group of sites on the lowland slightly inclined towards the Arctic Ocean; (2) the group of sites on the Sibirskiye Uvaly Highland; (3) the southern group of sites in the main Khanty-Mansiysk Lowland.

In all three regions, the morphoscopic analysis of the quartz sand grains from the deposits directly underlying the peat layers revealed a stable proportion of particles with almost spherical shape and mat surface. Such properties indicate that the sand grains were subjected to the aeolian transportation in subaerial environments.

However, the quartz grains from these three regions show a certain morphological difference. For example, in the northern region sand grains of marine origin occur along with the aeolian quartz particles. Such sand grains were formed during the marine transgressions under the influence of glaciers advancing into the sea both from the west and east, which caused a substantial influx of glacimarine and iceberg material.

The morphology of quartz sand grains from boreholes in the middle region, on the uplands of the Sibirskiye Uvaly (Siberian Hills), is characterised by stable predominance of aeolian particles. It is very different from that in the northern region.

The data on the sand grains morphology in the southern region of the Plain show that medium-rounded and slightly matted grains and shiny grains occur along with well-rounded and matted aeolian grains. Such a variety of types in the southern region can be explained by its geomorphological features and history. It consists of several large depressions, where, beginning from the Middle Palaeogene, stages of limnic and alluvial activity alternated with the arid aeolian phases.

The radiocarbon dates from the peat cover of the studied regions show that the reported stage of aeolian activity ended during the Younger Dryas cold event, before the beginning of the Holocene when the process of paludification has begun.

Therefore, during the Late Glacial (and probably beginning from the maximum cooling 18-20 kyr B.P.) a vast area, with environments and climate similar to a cold desert, occupied the central and northern parts of West Siberian Plain. In the southern part of the Plain cold deserts were replaced by areas of loess accumulation. The cold deserts could be an important source of the dust particles for the loessic sedimentation.

Reference:

Timireva S.N. and Velichko A.A. The West Siberian Plain as a late glacial desert. Correlation of Pleistocene Events in the Russian North. International Workshop Abstracts. 4-6 December 2006. Saint-Petersburg, 2006, p. 104.