ИСТИНА

The Russian plain in the second half of the Holocene seems to be an arena of complex interactions of different civilizations. Ethnic shifts were largely determined by the climatic rhythms recorded in the buried soils of archaeological sites. In this regard, paleolandscape reconstructions are important for understanding the causes of ethnic shifts and migration waves. Landscape evolution was studied based on detailed morphological, analytical and microbiomorphic research of the soil chronosequence that included surface soils and soils buried under burial mounds of the Bronze Age (Tokhmeyevo kurgan cemetery, Chuvashia Republic, Mihailov, et al., 2014). Soils are formed on similar surfaces in similar loess parent material at the same elevation under the broadleaved forest. Both buried and surface soils meet the criteria for Glossic, Folic, Albic, Dystric Retisol and show similar morphology and key analytical features (Fig. 1a, 2a, b, c, d) indicating close similarity of the landscapes in the study area that existed from the Bronze Age to nowadays. The burial mound is composed of mud blocks with central parts made of material of the E horizons and covered by the material of Bt horizons enriched in fluvial sand grains (Fig. 1b, c, d, e). The use of these materials in the burial mound construction is an independent proof of the presence of E and Bt horizons in the soil of the Bronze Age. Microbiomorphic assemblages (Golyeva, 2001) support this conclusion, showing a bit more humid climate during the Bronze Age comparing to the present (Fig. 2e, f). The presence of black humus cutans on top of brown clay cutans in the Bt horizons of the buried soils also correlates with more wet soil moisture regime (Fig. 2g, h). Bt horizons of the surface soils have only brown clay cutans. These conclusions are also supported by earlier published data on soil chronosequence that included surface soils and soils buried under fortification earth wall of the Early Iron Age: Glossic, Folic, Albic, Dystric A B C D Mud block, central part; E horizon of the buried soil. Retisols of Sareevo Settlement are formed in similar environment of the broadleaved forest, in mantle loams and close to Tokhmeyevo kurgan cemetery (Makeev et al., 2019). The study of the soil chronosequence in the Tokhmeyevo kurgan cemetery is also complemented by the previous study Taushkasy kurgan cemetery of the Bronze Age where the surface and buried soils were formed in the derivatives of the Permian sandstones (Folic Eutric Cambisols, Aseeva, et al., 2019). Soils of the three archaeological monuments could be combined in one chronosequence that includes soils of the Early Iron Age and the Bronze Age formed in parent rocks that differ in their response to environmental impact (different features of soil memory, Targulian, and Goryachkin, 2008). This chronosequence displays the stability of forest environment at the southern boundary of the forest belt from the Bronze Age to the present. Landscape stability in the studied area makes it possible to establish the northern limit of the wide belt, which stretches out from the dry steppe to the northern forest-steppe, where landscape shifts influenced by the Late Holocene climatic cycles resulted in a combination of polygenetic features of forest and steppe pedogenesis in the surface soils. Fortification walls of the Early Iron Age and burial mounds of the Bronze Age are not only indicators of landscape dynamics, but also the unique cultural heritage of the East European Plain. Further studies will link the critical stages of landscape evolution with the migration waves of the ancient tribes.