ИСТИНА

Archaeological monuments, such as fortification ramparts and burial mounds are widely spread in the Russian Plain. Soils buried under these monuments are valuable archives of paleoclimatic information since they help to reveal the patterns of landscape variation during Mid- to Late Holocene. The present study was focused on the reconstruction of paleoenvironmental conditions in the central part of European Russia (forest-steppe zone and the adjacent southern edge of the forest zone). In the forest zone, three archaeological sites located close to each other: kurgans of two burial grounds of the Bronze Age and fortification rampart of the settlement of the Early Iron Age, were studied in the Republic of Chuvashia. According to the studies of peat sequences along the southern fringe of the forest zone forest environment persisted in the southern part of the forest zone since the Early Holocene (Novenko et al., 2015; 2019). Thick mollic horizon and spore-pollen data in buried soils indicate that soils of the Bronze Age were formed under an open parkland forest with wide participation of grasses. The radiocarbon dates (about 5.5 kа) indicate that mollic horizon was formed not later than Mid-Holocene. Comparison between surface and buried soils in the Bronze and Early Iron Age confirms landscape stability in the forest zone. In the central part of the forest-steppe zone, archaeological monuments of the Early Iron Age and Medieval included three settlements in Lipetsk region with soils buried under defensive ramparts of different age (~2500-2300-1500 yrs BP). One settlement of the Early Iron Age was studied in the southern part of the forest-steppe zone in Belgorod region and included soils buried under two ramparts dated at 2450 ± 40 years BP. Studies of the soils buried and surface soils showed that environmental conditions since Early Iron Age were resembling. Surface and buried soils 2500-2300 yrs BP (Greyzemic Luvic Phaeozems) contains Greyzemic features manifested as uncoated silt and sand grains on ped faces in the lower part of a mollic horizon, however, carbonate coatings above clay cutans have been found in soils buried 2500 yrs BP which points on recent aridization in the central part of the Russian Plain. Buried soils ~2300 years BP showed leaching of carbonates, and well-defined Greyzemic features in the lower part of the Ah horizon, sometimes showing clearly defined E horizon, which indicates an increase in climate humidity. High carbonate table, carbonate coatings above clay cutans, hard carbonate neoformations and the appearance of new krotovinas were noticed in the soil profile in soil buried 1500 yrs BP. Phytoliths analysis of this soil showed that grassy meadows replaced forest vegetation, which confirms the peak of arid climatic conditions at this time interval. It could be concluded, in the forest-steppe zone, the climatic changes led to noticeable changes in vegetation cover and soil evolution. This research was supported by the Russian Science Foundation (Project No. 19-18-00327).