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ACSYS Final Science Conference: Book of Abstracts

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TitleChironomid-inferred Holocene mean July air temperatures for the Lena River Delta area, East Siberia, and the Kola Peninsula, Northwestern Russia 
First AuthorIlyashuk, E.A
Organization: Institute of North Industrial Ecology Problems
Country: Russia
E-Mail: Elena.ilyashuk@inep.ksc.ru
Co-AuthorIlyashuk, B.P.
Andreev, A.A.
Bennett, K.D.
Hammarlund, D.
Hubberten, H-W. 
Session1- The State of the Arctic Climate System 
AbstractQuantitative palaeotemperature reconstructions in the Arctic and Subarctic regions are important for understanding of climatic dynamics, and can be used as means of extending our knowledge on long-term natural climate variability that allow current climate models to be tested and validated. The non-biting midges (Diptera: Chironomidae) are now accepted as being one of the best biological palaeoclimate proxies. Radiocarbon-dated chironomid records from Lake Nikolay (7320'N, 12412'E) and Lake Berkut (6621'N, 3640'E) provided the detailed palaeotemperature reconstructions for the Holocene in the Lena River Delta area, East Siberia, and southern Kola Peninsula, Northwestern Russia, respectively. Mean July air temperature (TVII) reconstruction was done using a weighted averaging partial least squares model based on a chironomid calibration data set from northern Sweden. Palaeotemperature reconstructions for Lake Nikolay imply the warmest (with TVII up to 2-3C warmer than nowadays) climate during ca. 10,200-9200 cal. yr BP. Thereafter climate became unstable, with short warm oscillations at ca. 5600 and 4500-4100 cal. yr BP, and a relatively long warm period ca. 2300-1400 cal. yr BP. During the last few centuries minor cooling trends are noted in the region. Reconstructed present TVII is 8.5oC. Midge assemblages from Lake Berkut in the early Holocene (10,100-9000 cal. yr BP) suggest a climate warmer (with TVII up to 13.2C) and moister than modern. The Mid-Holocene period (8400-2400 cal. yr BP) is inferred to contain a cooling trend (TVII decreased gradually by about 2.5C) with major warm oscillation ca. 6000-4000 cal. yr BP (with TVII about 12.0C). Midge assemblages in the late Holocene (2400 to 0 cal. yr BP) indicate a warming trend with a relatively cold climate during ca. 2400-1200 cal. yr BP and warmer climate during the last 1200 years. Present-day chironomid-inferred TVII is 12.5C, corresponding to the meteorological data of the 20th century in this area. 
TypePoster 10
DownloadExtended Abstract: PDF, 74 KB
Poster: PDF, 219 KB

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