Paleoenvironmental studies of lakeside watershed settlements of the Tobol-Ishim interfluve (Zolotoe 1 settlement, Kurgan Oblast)
During the study of the process of settling people in the territory of the forest-steppe and steppe zones of Western Siberia, both valleyside settlement sites of the Bronze Age and watershed lakeside settlements have been identified. The settlement of Zolotoe 1 is one of the few sites of the Late Bronze Age investigated by excavations and confined to the vast water-dividing surface between the rivers Tobol and Ishim in Kurgan Oblast. Two stages of population have been identified, associated with the Alakul and Alekseyevka-Sargary Cultures. Despite the change of the resource base from alluvial to watershed, the archaeological materials do not indicate differences in the economies and traditions of the Alakul population of this watershed settlement from the analogous valley sites. Due to the lack of data on the environment of such watershed settlements of the Bronze Age, the analysis has been carried out on the pollen data from the benthal deposits of Lake Zolotinskoe nearby the settlement (off-site data), carbonated macro-residues from various archaeological contexts of the occupational layer (on-site data), and the soil profiles on the settlement and beyond it (on-site data). By means of the radiocarbon dating it was found that the palynological data from the lake core sample show the environmental conditions of only the last third - end of the 2nd millennium BCE, beginning from the 24th century BCE; hence, it has not been possible to reconstruct the specifics of the natural environment surrounding the Alakul population of the site during the first phase of the settlement. The overall environmental background for the time depth of the Alakul Culture has been analyzed on the data from the neighboring regions. It appears that it does not correspond with the arid phase but is related to warm, but moderately humid conditions. However, already in the middle of the 2nd millennium BCE (3,500-3,300 cal. BP), probably, there were changes towards more arid and/or warm climate, which brought about adverse conditions for the forestation in the forest-steppe, advance of the steppe and a lowering of the groundwater table. This is also confirmed by the results of the study of Lake Zolotinskoe. Beginning from the 24th century BCE, the watershed areas of the Tobol basin were dominated by open meadow-steppe landscapes with small birch forests, while the climate was more arid than it is today. The lower part of the lake waterside was heavily waterlogged; the lake probably shoaled in summer, but did not overdry. Such a natural environment was the background for the second period of population of the settlement by the bearers of the Alekseyevka-Sargary Culture and, probably, was not changing up until the end of the 2nd millennium BCE. The most part of the carbonized macro-residues of the Alakul and the Sargary cultural layer belongs to ruderal flora, which suggests a long-term inhabitation on the settlement. The analysis of the soil buried underneath the cultural layer suggests that during the emergence of the settlement the natural conditions were similar to modern, but differed in a better water availability.