Landscape change and occupation history in the Central Russian Upland from Upper Palaeolithic to medieval: Paleopedological record from Zaraysk Kremlin

Abstract

Paleosol-sedimentary sequences encountered in the settlements with long occupation history could provide a unique insight into the trends of landscape development and human-environment interaction over long time scales. We studied paleosols exposed by the excavations in the Kremlin of Zaraysk (Central European Russia) which were formed during the late Pleistocene and the Holocene and contain archaeological materials spanning from Upper Palaeolithic till late Medieval. Archaeological findings and numerous radiocarbon dates provide a reliable time frame for paleopedological record which we extracted from paleosols using macro- and micromorphological observations as well as physical and chemical properties and paleobotanical indicators (phytolith assemblages). The basal layer without archaeological materials presents signs of soil formation which resemble Bryansk fossil soil developed in the second half of Marine Isotope Stage (MIS) 3. The overlying archaeological stratum - one of the Gravettian cultural layers is linked to the paleosol level known as Zaraysk soil. Its age is estimated at 16 ka BP. Macro- and micromorphological features point to moderate dark humus accumulation, anthropogenic compaction and cryogenic processes at the final stages of paleopedogenesis. Poorly sorted heterogeneous composition of the mineral material with a large proportion of sand grains indicates colluvial origin of the paleosol parent material. The overlying sorted silty deposit supposes contribution of windblown material to its formation. We associate cryogenic and eolian processes at the end and after Zaraysk soil development with the cold intervals at the end MIS 2, presumably with the Oldest and Younger Dryas. The complete profile of Luvisol/Grey Forest Soil with eluvial and illuvial horizons and relict dark humus morphons is developed within the silty unit. This soil indicates long-term natural pedogenesis under first steppe and then deciduous forest vegetation during major part of the Holocene. The topsoil however is formed by clear plough horizon which points to cultivation started in the Middle Ages. Sharp boundary separates the buried Luvisol from the overlying cultural layer-Technosol developed after building of Zaraysk Kremlin in the 16th century. Technosol presents a mixture of natural soil with construction materials, especially limestone fragments. Soil units, both natural and affected by humans, are not separated one from another by an unaltered C horizon, so soil-forming processes from the upper soils penetrate into the underlying ones forming a multistory pedocomplex.