Holocene climate variability on the Kola Peninsula, Russian Subarctic, based on aquatic invertebrate records from lake sediments

摘要

Sedimentary records of invertebrate assemblages were obtained from a small lake in the Khibiny Mountains, Kola Peninsula. Together with a quantitative chironomid-based reconstruction of mean July air temperature, these data provide evidence of Holocene climate variability in the western sector of the Russian Subarctic. The results suggest that the amplitude of climate change was more pronounced in the interior mountain area than near the White Sea coast. A chironomid-based temperature reconstruction reflects a warming trend in the early Holocene, interrupted by a transient cooling at ca. 8500-8000. cal. yr. BP with a maximum drop in temperature (ca. 1°C) around 8200. cal. yr. BP. The regional Holocene Thermal Maximum, characterized by maximum warmth and dryness occurred at ca. 7900-5400. cal. yr. BP. During this period, July temperatures were at least 1°C higher than at present. The relatively warm and dry climate persisted until ca. 4000. cal. yr. BP, when a pronounced neoglacial cooling was initiated. Minimum temperatures, ca. 1-2°C lower than at present, were inferred at ca. 3200-3000. cal. yr. BP. Faunal shifts in the stratigraphic profile imply also that the late-Holocene cooling was followed by a general increase in effective moisture.