Holocene development of soils in response to environmental changes: the Novosvobodnaya archaeological site, North Caucasus

Soil-archaeological studies in North Caucasus indicate that the expansion of broad-leaved deciduous forests from mountains to foothills and piedmont plain took place about 3000 years ago, after the Middle Holocene steppe stage. At this time, steppe Chernozems transformed into Luvisols under forests. Often the Luvisol profiles preserve the relict humus horizon and paleokrotovinas (mole tunnels) inherited from the chernozemic stage. Within the same period, normally developed soils evolved on the surface of burial mounds: Luvisols on mounds composed of loess and chernozemic material and Rendzinas and Luvisols with a calcareous horizon on loamy mounds with a limestone paving (stone armour) used to strengthen the mounds. The rates of profile differentiation and some pedogenic processes have been calculated. In the eluvial horizons of Luvisols developed on loess or charnozemic material, the rate of clay loss was up to 7–8 g m−2 year.