Environmental Changes in the North-East of the Buryat Republic (Russia) Since the Holocene Optimum: First Results
E. V. BEZRUKOVA1,2, A. A. AMOSOVA1, V. M. CHUBAROV1, A. L. FINKELSHTEIN1, N. V. KULAGINA3
1Vinogradov Institute of Geochemistry, SB RAS, 664033, Irkutsk, Favorskiy str., 1A
2Institute of Archaeology and Ethnography, SB RAS, 630090, Novosibirsk, Acad. Lavrentiev ave., 17
3Institute of the Earth Crust, SB RAS, 664033, Irkutsk, Lermontov str., 128
Keywords: Северная Бурятия, оз. Баунт, геохимические и палинологические индексы, палеоэкологические реконструкции, природная среда, средний-поздний голоцен, Northern Buryatia, Lake Baunt, geochemical and pollen records, palaeoecological reconstruction, environment, Middle-Late Holocene
Abstract
The article presents the first high resolution geochemical and pollen records from sediments of the Lake Baunt (55'11'15" N and 113'01'45" E), located within the continuous permafrost zone. Those records were used to obtain the first reconstructions of the environment and climate of the north Buryatia including the weathering conditions in the catchment area in the post-optimal time of Holocene. Over the last 7000 years the environment and climate on the north-east of Buryatia were heterogeneous. A relatively warm and dry climate was reconstructed for the end of the Holocene Climatic Optimum between 6900 and 6000 yrs BP. Later at about 6000-1500/1000 yrs BP the climate became colder that might have led to weakening of chemical weathering processes at more intense permafrost processes. The climate over the last 1500-1000 yrs BP was colder than today. The calculated environmental indices show different values in sediments of relatively warm and relatively cold intervals and reflect sedimentation conditions that have been controlled by climatic changes.
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