Trends and rates of holocene soil evolution in the North Caucasian Piedmont

In the piedmont of the North Caucasus a 3500 yr B.P. steppe was replaced by forest as climate became moister. Steppe Chernozems were preserved under high (up to 8 m) burial mounds (kurgans) constructed about 5000 yr B.P. On natural landsurfaces surrounding the kurgans, Chernozems evolved to Luvisols. On the kurgans made of loess and Chernozem soil, mature Luvisols formed during the forest stage. On the kurgans covered with artificial limestone paving, the Luvisol profile is less developed. Migration and transformation of substances occur throughout the whole kurgan pile. These include fissures and earthworm channels filled with clay-humus material or secondary carbonates, gleyed mottles, iron oxides, and neoformed gypsum. These processes cause diagenetic transformation of buried Chernozems even at depth.