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A multiproxy record of Holocene environmental changes from the northern Kuril Islands (Russian Far East)

Anderson, Patricia, Minyuk, Pavel, Lozhkin, Anatoly, Cherepanova, Marina, Borkhodoev, Vladimir, Finney, Bruce
Journal of paleolimnology 2015 v.54 no.4 pp. 379-393
Bacillariophyceae, Pinus, carbon, freshwater, islands, lakes, landscapes, limnology, lowlands, meadows, paleontology, palynology, sea level, sediments, shrubs, snowpack, summer, temperature, transgressive segregation, tundra, Okhotsk Sea, Russia
Diatom, rock magnetic, geochemical, and lithological studies of a sediment core from Paramushir Island (northern Kuril Archipelago) trace environmental shifts from bog to salt-water lagoon to freshwater lake over the past 10,000 ¹⁴C BP. Organic-rich mesic landscapes dominated the southern island until ~8200 ¹⁴C BP. Transgression of the Sea of Okhotsk onto the island began sometime after 8200 ¹⁴C BP, resulting in the formation first of a salty (~8200–5700 ¹⁴C BP) then a brackish (~5700–5200 ¹⁴C BP) lagoon. With lowering of sea level after 5200 ¹⁴C BP, a freshwater lake formed, which has remained to the present day. This history parallels regional trends in the Russian Far East, where maximum sea levels occurred between ~8000 and 4600 ¹⁴C BP, peaking at ~6400 ¹⁴C BP. Sandy levels within the lake core suggest four intervals of aeolian activity (~4900–4800 ¹⁴C BP; 4300–3800 ¹⁴C BP; 3200–3000 ¹⁴C BP; 1900–900 ¹⁴C BP), perhaps related to drier than present climates. Palynological data indicate a dominance of Pinus pumila–Duschekia kamtschatica shrub tundra in the lowlands ~8200–5800 ¹⁴C BP, marking the Holocene thermal maximum. This vegetation contrasts to modern, which established ~5800 ¹⁴C BP and is a mix of coastal meadow, Betula–Salix low shrub tundra, and scattered Pinus and Duschekia thickets. The palynological record shows little response to mid-to-late Holocene climatic fluctuations except for a decrease in Pinus shrubs perhaps caused by changes in snow cover and/or summer temperature during the Little Ice Age.