Landscape Changes in the Southern Russian Plain in the Late Pleistocene: a Case Study of the Loess-Soil Sequence in the Azov Sea Region

Abstract

Based on the complex studying 10 meter thick loess-soil sequence in the Beglitsa section (47°08° N, 38°31° E), the landscape and climate changes in the north-eastern Azov Sea Region in the Late Pleistocene were reconstructed. The intensity of loess accumulation decreased in the interglacial and interstadial conditions, when the soil-forming processes prevailed, and increased in cryoarid conditions of the glacial epoch, and especially, during the Late Valdai. As indicated by topography of palaeosoil horizons, loess layers of various ages envelope in sequence the primary fluvial (erosional-accumulative) relief. Loess accumulation resulted in general rise of the terrace surface. It preserved the major features of original topography but gradually smoothed the minor ones. During the entire Late Pleistocene the studied area belonged to the steppe zone. Participation of forbs in steppe communities, as well as the grass cover density, decreased in the cryoarid periglacial conditions and increased under warmer and less continental interstadial or interglacial climate. The role of intrazonal tree communities (pine forests with steppe elements, birch and alder wet forests) remained minor even in the most favorable climate of the Mikulino Interglacial, when the broad-leaved trees (mainly Quercus) participated in the forests. During the interstadial warm phases of the Valdai glacial epoch, the trees growing at present in the severe continental climatic conditions (Larix, Pinus sibirica) occurred in the region. As in the present time, near the shore of the Azov Sea, the areas with disturbed soil cover, including those with saline soil, were widespread due to abrasion, development of slumps and landslides, and erosion.