INTERACTION OF ALLUVIAL AND SOIL FORMATION PROCESSES AT DIFFERENT STAGES OF THE FLOOD PLAINS DEVELOPMENT DURING THE HOLOCENE (THE RIVERS OF THE CENTRAL PART OF THE EAST EUROPEAN PLAIN AS AN EXAMPLE)

The paper generalizes the data of the alluvium accumulation and soil formation rates in the flood plains of the plain rivers. The method of assessment is based on facies analysis of flood plain deposits containing series of buried soils. The Middle Oka, the Moscow, the Upper Don, and the Nepryadva rivers were investigated. The correlation of paleogeographic events with the conditions of soil formation and human activity in the Holocene were revealed, the stages of soil formation were discovered. We established that at the rate of accumulation more than 0.25 cm/y the soil formation doesn’t change the alluvium, at the rate of 0.1-0.25 cm/y the alluvium have traces of the soil, at the rate of 0.03-0.1 cm/y the cumulative sod-layered soils appear, and at the rate of 0.01-0.03 cm/y the well-developed sod and meadow soils are forming.