Description: Pollen, plant macrofossil, loss-on-ignition and radiocarbon analyses of a 1.4-m section in thermokarst topography from Faddeyevskiy Island (75°20'N, 143°50'E, 30 m elevation) provides new information on Late Pleistocene interstadial environmental history of this high Arctic region. Conventional radiocarbon dates (25,700 ± 1000, 32,780 ± 500, 35,200 ± 650 yr BP) and two AMS dates (29,950 ± 660 and 42,990 ± 1280 yr BP) indicate that the deposits accumulated during the Kargian (Boutellier) interval. Numerous mammoth (Mammuthus primigenius) remains that have been collected in vicinity of the site in this study were radio-carbon dated to 36,700-18,500 yr BP. Rare bison (Bison priscus) bones were dated to 32,200 ± 600 and 33,100 ± 320 yr BP. Poaceae, Cyperaceae, and Artemisia pollen dominate the spectra with some Ranunculaceae, Caryophyllaceae, Rosaceae, and Asteraceae. The pollen spectra reflect steppe-like (tundra-steppe) vegetation, which was dominant on the exposed shelf of the Arctic Ocean. Numerous Carex macrofossils suggest that the summer climate was at least 2°C warmer than today. The productivity of the local vegetation during the Kargian interstadial was high enough to feed the population of grazing mammals.

Description: The object of research is the Holocene massive ice veins on the Eastern coast of the Daurkin Peninsula, the easternmost part of the Chukotka. Peat bogs with ice veins occur on the surface of marine terraces (near Uelen and Lorino settlements) and on flood plain of the Koolen' Lake; the thickness of peat varies from 0.7 to 2.5 m. Radiocarbon dating of the peat enclosing the investigated ice veins near Uelen and Lorino indicated that the beginning of peat accumulation began at the end of Late Pleistocene - early Holocene, about 11 cal ka BP. On the flood plain of the Koolen' Lake peat bogs began to accumulate in the middle Holocene, i.e. around 6 cal ka BP. At the initial stage of peat bogs formation the rate of peat accumulation was high and could reach 1 cm/10 years. Ice veins occur at a depth of 0.5-1 m, and their lower parts are located in the underlying peat sandy loams and loams. In the upper levels of the peat bogs, narrow present-day ice veins are found, which are sometimes embedded in the upper parts of Holocene veins. A clear sign of syngenetic growth of veins is the upward bending of the layers of the host peat at the lateral contacts with the veins. The main source of water for the formation of ice veins is snow, as evidenced by the ratio of stable isotopes of oxygen and hydrogen and the values of deuterium excesses in the ice. A slight admixture of saline water (probably from a seasonally thawed layer) was noted in the veins near the Lorino settlement. Reconstructions of winter air paleotemperatures, performed on the basis of data of isotope-oxygen composition of ice from the veins, did show that at the period between 11 and 6 cal Ka BP, the mean winter air temperature on the Daurkin Peninsula was by 2-5 °C lower than today, but the air temperature of the coldest month (January or February) was still lower (by 4-8 °C) than today. The noticeable trend of increase of stable isotope values in the ice veins from early Holocene to the present time is indicative of a steady positive trend of mean winter air temperatures in the Holocene.