Reconstruction of Climate and Landscapes of the Medieval Period on the Basis of Palynological Study of Paleosols Buried under Kurgans and Dendrochronological Data from Altai (South of Western Siberia)

Autor: V. E. Prikhod’ko, M. V. Mikharevich, Vladimir S. Myglan
Rok vydání: 2020
Předmět:
Zdroj: Eurasian Soil Science. 53:544-557
ISSN: 1556-195X
1064-2293
Popis: Light loamy ordinary chernozems buried under two kurgans of a large Early Medieval necropolis Srostki-1 constructed in 890 ± 105…975 ± 85 AD (calibration by 1δ) were compared with the chernozem of the background territory in Biysk district of Altai. The analysis of pedological and 20 geochemical indices characterizing weathering, biological activity, and salt leaching demonstrated that the paleosols of the Medieval period in the phase before the construction of the kurgans had been formed in a somewhat drier climate compared to the modern conditions, and then the humidization of the paleoclimate began. According to palynological data, the considered period was characterized by a decrease in the area of pine stands, which could be due to colder winters. The areas of birch and riverine willow forests also decreased in comparison with the modern period because of the active cutting by humans of the Srostki ethnos. In the Medieval period, mesophytic rich forb communities occupied larger areas and predominated over dry-steppe communities. The growth of sedges was active on expanding marshes that appeared after drying of shallow water bodies upon the decrease in the water-protective role of forest vegetation. At the same time, a slight increase in the amount of pollen of xerophytic herbs, including representatives of Chenopodiaceae and Poaceae families and Artemisia genus took place. This could be related to the increased anthropogenic load, including soil disturbance upon the construction of 61 kurgans of the Srostki culture. Dendrochronological method was applied to reconstruct average summer temperatures over the past two thousand years. It was found that the heat supply of summer seasons in the Srostki period (8th–12th centuries AD) generally corresponded to that at present. However, the years of 850–870 and 930–950 AD were marked by summer cooling, and the years of 876–882 and 982 AD were marked by summer warming with average summer temperatures 1.5°C higher than the reference values of 1961–1990. The climatic variability of the Medieval period in different regions of the south of Western Siberia attests to the metachronous dynamics of the climate specified by the local conditions against the background of general climatic trends typical of Central Asia.
Databáze: OpenAIRE
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