Palaeoenvironment of MIS5 in the North of Western Siberia, reconstructed on the sub-fossil insect, crustacean and plant macrofossil data

Abstract

Insect, tadpole shrimp and plant macrofodssil assemblages dated to different intervals of MIS5 are presented for three sites in the northern part of the West Siberian plain: Karymkarskyi sor, Belaya Gora and Kiryas. The beetle faunas suggest a relatively warm climate associated with boreal forest and marsh communities of the middle and southern taiga type; this interpretation is in agreement with the paleobotanical studies. Evidence of warm climate is provided by the occurrence of the carabid beetle Trechus secalis, found in Karymkarskyi sor and Belaya Gora sites. This fossil occurrence is referred substages to MIS5e and MIS5c on the basis of TL and U/Th dates, and coincides with the presence of bark beetle remains at the Kiryas locality. Both plant macrofossils from the Belaya Gora locality and tadpole shrimp remains from Kiryas site do not include species indicative of warmer-than-present climate, despite the presence of residues of woody plants. Our data were compared with paleobotanical data from a number of locatities in the central and northern parts of the West Siberian plain that have been dated to MIS5 on the basis of TL and Th/U dates. Most of these sites yielded paleobotanical data indicative of relative warm climate and forest vegetation. The exception is the Elizarovo point site, where the palynological data indicate periglacial environments. Insect, crustacean and plant macrofossil data are well correlated with the results of studies of fossil insect and paleobotanical data from other regions of Northern Eurasia and may confirm warm and humid climate during some periods of MIS5 (substages 5e and 5c) and distribution of forest landscapes and corresponding insect complexes.