Variability of the Carbon-Isotope Composition (13С/12С) of Soils and Cultural Layers of Geoarchaeological Monuments on the Russian Plain

摘要

Abstract The practice of using isotope analysis in archaeological research, which has been developed in recent years, requires knowledge of the features of isotope fractionation in cultural layers and buried soils. The structural properties of geoarchaeological sites are determined by the local relief, climate, vegetation, landscape hydrology, and physical and chemical properties of soil-forming and underlying rocks, and the existence of cultures, and, therefore, their isotopic signature has a complex cumulative character. The aim of this work was to study the variability of the carbon-isotope composition of soils, rocks, and cultural layers of various landscape parts of geoarchaeological mounds in different natural zones of the Russian Plain to identify general climatic trends and the contribution of the anthropogenic factor to carbon isotope fractionation. The defensive ramparts of the Dmitrov Kremlin (Moscow oblast), Davydovo ancient settlement (Tambov oblast), Vodyanskii ancient settlement (Volgograd oblast), and necropolises of the Zhereno and Kvetun’ archaeological complexes (Bryansk oblast) were chosen as study objects. It is shown that a significant variability in the carbon-isotope composition is typical for soils and cultural layers of geoarchaeological locations of different natural zones and enables us to identify the stages of stable soil formation on the surface of embankments and the stages of backfill structures. The isotopic ratios decrease in the humus horizons of modern and buried soils. An increase in isotopic ratios is characteristic of the cultural layers of geoarchaeological objects in all natural zones and marks the epochs of the existence of cultures; however, the mechanisms of this process require further research. Despite the predominant distribution of herbaceous vegetation on the day surface of the sites, the isotope signature of buried soils reflects the type of dominant zonal vegetation and, using the features of the photosynthesis type, enables the reconstruction of climate features in the region at various chronostages of the object existence.