Н.Б. Лаврова, Л.В. Филимонова.
Использование анализа ископаемой флоры для реконструкции растительности и палеоэкологических условий позднеледниковья Карелии
// Труды КарНЦ РАН. No 10. Сер. Экологические исследования. 2018. C. 27-43
N.B. Lavrova, L.V. Filimonova. Using the fossil flora composition analysis for the reconstruction of vegetation and palaeoecological conditions during late glacial time in Karelia // Transactions of Karelian Research Centre of Russian Academy of Science. No 10. Ecological Studies Series. 2018. Pp. 27-43
Keywords: pollen spectra; macrofossils; fossil flora; palaeovegetation; Late Glacial period; Karelia
The paper summarizes the results of pollen and macrofossil studies of late glacial deposits in Karelia, encompassing the Older Dryas, Allerod, and Younger Dryas – 12350–10300 14С yrs BP (14100–11900 cal. yrs BP). Specific features of the composition and formation of spore-pollen spectra (SPS) are considered. SPS of late glacial deposits in Karelia were found to contain pollen and spores of plants from surrounding habitats, as well as redeposited pollen grains and those coming from long-range transport. Interpretation of late glacial palaeobotanical data and reconstruction of the respective plant cover employed palaeoecological analysis and the method of measuring pollen concentration in deposits. The geographical and eco-sociological analysis of the fossil flora was carried out. A majority of species were found to have had circumpolar distribution; somewhat fewer species had Eurasian ranges; the third position is shared by Holarctic, circumboreal, and European species. The flora includes arctic-alpine, low-arctic, arctic, steppe, and boreal species. Having analyzed micro- and macrofossils, we identified plants belonging to forest, tundra, forest-tundra, steppe, and meadow communities, pioneer groupings on immature or disturbed soils, stony and gravely substrates. The identified plants are indicators of late glacial ecological conditions. They have different requirements to heat and moisture, texture and geochemical composition of the underlying deposits. The integrated analysis of the fossil flora and pollen concentration measurements have enabled more accurate reconstructions of late glacial vegetation. According to them, the complex natural and climatic conditions, as well as the high variation of landforms and Quaternary deposits composition have resulted in a very specific plant cover, with no modern analogs to be found. The cover did not form a closed canopy, was mosaic, and included species that were diverse both ecologically and in terms of geographic provenance. In Karelia at 12350–10300 14С yrs BP (14100–11900 cal. yrs BP), periglacial-steppe and tundra communities were widespread, and there occurred also birch and alder forest-tundra communities. Climate change during late glacial cooling (stadial) and warming (interstadial) events altered their spatial shares, but the composition of the flora persisted.
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