Soils and cultural layers of ancient cities in the south of European Russia

Abstract

Antique cities in the south of European Russia are characterized by a considerable thickness of their cultural layers (urbosediments) accumulated as construction debris and household wastes. Under the impact of pedogenesis and weathering in dry climate of the steppe zone, these sediments have acquired the features of loesslike low-humus calcareous and alkaline deposits. They are also enriched in many elements (P, Zn, Ca, Cu, Pb, As) related to the diverse anthropogenic activities. The soils developed from such urbosediments can be classified as urbanozems (Urban Technosols), whereas chernozems close to their zonal analogues have developed in the surface layer of sediments covering long-abandoned ancient cities. Similar characteristics have been found for the soils of the medieval and more recent cities in the studied region. Maximum concentrations of the pollutants are locally found in the antique and medieval urbosediments enriched in dyes, handicrafts from nonferrous metals, and other artifacts. Surface soils of ancient cities inherit the properties and composition of the cultural layer. Even in chernozems that developed under steppe vegetation on the surface of the abandoned antique cities of Phanagoria and Tanais for about 1000—1500 years, the concentrations of copper, zinc, and calcium carbonates remain high. Extremely high phosphorus concentrations in these soils should be noted. This is related to the stability of calcium phosphates from animal bones that are abundant in the cultural layer acting as parent material for surface soils.