We present an attempt to reconstruct environments for the Late Pleistocene time span 32 to 24 kyr based on recently obtained geochronometric, palaeofaunistic, geologic and geomorphic data. The study area is limited by the 60th parallel and includes northern and northeastern regions of European Russia, north of West and East Siberias and the Russian North-East. Taking into account the diversity of palaeoenvironments during this interval, the reconstructions are based on selected sequences equipped with reliable radiocarbon and palaeobotanical data. The bulk of them relates to the time span of 28 to 26 kyr when the last warming occurred before the onset of the Valadai (Sartan) glaciation.

The following natural zones are distinguished for this time span: 1) arctic tundra, 2) sedge and grass-moss tundras, 3) shrub tundra with dwarf birch and Alnaster, with dwarf pine in East Siberia, 4) grass tundras with patches of xerophyte communities, 5) forest-tundra, 6) spruce-birch parklands, 7) spruce-birch parklands with Siberian pine and larch, 8) spruce-birch and pine forests, in places with furtree, 9) spruce cum Siberian pine forests with larch, 10) tundras and parklands in uplands and mountains with local cirque and valley glaciers.

Compared to the subsequent cold stage (LGM, Valdai, Sartan time) tundra was less extensive, and periglacial landscapes with meadow-steppe communities were confined to eastern Siberia. During the Briansk interval great expanses were occupied by sedge, grass-moss, shrub tundras and forest-tundra which in Trans-Uralia weres descending down to 65°N. The modern limit of tundras is located much farther north. Parkland type forests of the Briansk interval were occupying the area where periglacial tundra-steppe predominated during the Valdai (Sartan) time. East of the Urals vegetation communities were often dominated by Siberian pine and larch. Presently boreal forests prevail in this area: dark coniferous forests of middle taiga west of the Urals and spruce/furtree/Siberian pine formations and larch forests east of the Urals.

The palaeoclimatic reconstructions have been based on palaeoflorisric research accompanied by climatograms which contain information of temperature boundaries allowing cohabitation of the plants. The Briansk climate was first of all distinguished by the winter (January) temperatures which in European Russia (e.g. the Vologda Region) were by 11° and in northern Cis-Uralia by 15° lower than the present ones. Summer temperatures were lower than the present ones only in northeastern European Russia and in the West Siberian north. In the Russain North-East, e.g. in the Indigirka catchment, January temperatures were significantly lower than the present ones (by с 17°). However, summer temperatures in piedmont terrains shielded from cold winds could be close to the present ones.

Reference:

Pisareva V.V., Faustova M.A. Reconstructing environments of the Late Pleistocene interval 32 to 24 kyr in the Russian North. Correlation of Pleistocene Events in the Russian North. International Workshop Abstracts. 4-6 December 2006. Saint-Petersburg, 2006, p. 74.