SUBRECENT POLLEN SPECTRA OF THE SOUTHERN PART OF ZABAIKALSKII KRAI AS A METHODOLOGICAL BASIS FOR THE RECONSTRUCTION OF PALEOVEGETATION
S. A. RESHETOVA1,2
1Institute of Natural Resources, Ecology and Cryology, Siberian Branch, Russian Academy of Sciences, ul. Nedorezova, 16a, Chita, 672014, Russia
2A. P. Vinogradov Institute of Geochemistry, Siberian Branch, Russian Academy of Sciences, ul. Favorskogo, 1a, Irkutsk, 664033, Russia
Keywords: палинологический анализ, климат, ландшафты, почвы, речной аллювий, озерные отложения, За байкалье, palynological analysis, climate, landscapes, soils, river alluvium, lacustrine deposits, Transbaikalia
Abstract
The article presents the results from studying and analyzing subrecent spectra of the Transbaikalian region. A palynological analysis is made of pollen spectra of the mountain-taiga and steppe-taiga and steppe zones as well as studying the spectra from different-facies deposits of four key areas. The scheme of vegetation is compiled for each key area, and a detailed analysis is made of the palynospectra. The study revealed special features in the composition of spectra of different vegetation associations and their correspondence to the composition of modern vegetation. It is shown that the spectra faithfully reflect its integral zonal, regional and local peculiarities. A comparative analysis is made of the spectra from deposits of different genetic types. The com positions of the spectra from soil, alluvial and lacustrine deposits are compared. The relationship of pollen from light- and dark-coniferous species is analyzed. Methods of multidimensional statistics are used, including Principal Component Analysis. A fun damental difference is revealed in the composition of spectra for mountain-taiga and steppe landscapes. It is established that the main background in the subrecent spectra for mountain-taiga and steppe areas, respectively, is composed of pollen from woody plants and grasses. An analysis is made of current climatic parameters as well as determining the character of correlation between the composition of the spectra and the main parameters of climate determining the evolution of modern vegetation producing pollen spectra. Important parameters are determined; the mean annual precipitation amount, and the index of continentality which are reliable indicators of change in climatic conditions when carrying out paleoclimatic reconstructions in Transbaikalia. It is established that spectra with maximum content of pollen from dark- and light-coniferous woody plants tend to occur in areas with different mean annual precipitation amounts and with different values of the index of continentality.
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