The stratal ice deposits represent one of the most dangerous cryogenic phenomena, which influences the economic activity in areas with permafrost development. This is particularly true in connection ...with intense development of Arctic areas, which required extensive studies of stratal ice deposits and their genesis. Such studies were conducted in the Shpindler Cape area, on the southern coast of the Baidaratskaya Estuary, near the Marresale and Kha rasavei settlements, in the western Yamal Peninsula, in the Bovanenkovo area, in the Yuribei River valley, in the Neito Lake area in the central part of the Yamal Peninsula, and in the Erkutayakh River valley.
The ice-rich core formation within the core of the lithalsa in the Sentsa River valley (West Buryatia) was studied. The concentrations of stable oxygen and hydrogen isotopes in the ice were ...determined, the plant residues in the enclosing deposits were aged. It was found that the lacustrine loams enclosing the ice body were accumulated about 4700–7000 years ago. The ice core of the lithalsa was characterized by δD values from 141.9 to–159.8‰, δ
18
O from–19.52 to–21‰, and
d
exc
within 4.1–17.29‰. Small variations in the isotope composition of the ice–soil material within the lithalsa core point to its formation in an open system with water inflow from outside. The values of δ
18
O and δD were much closer to those for recent middle-winter and late-autumn atmospheric precipitation, as well as for riverine water, which pointed to a Holocene age of the ice.
The isotopic features of Lake Trekhtsvetnoe in the White Sea coast area were studied in 2012–2015 in both winter and summer. Lake Trekhtsvetnoe is a water body, separating from the sea, with constant ...vertical stratification throughout the observation period. Its isotopic, hydrophysical, and biological characteristics have been studied. By the isotopic profile of lake water body, three zones can be identified in the lake: (1) 0–1 m: mixolimnion zone with δ
18
O varying from–12 to–11.1‰; (2) 1.0–3.0 m: zone with transitional properties with δ
18
O varying from–11.1 to–5.5‰; (3) 3.0–7.6 m: monimolimnion zone with highest values of δ
18
O—from–5.5 to–4.7‰.
The isotope-oxygen composition of ice wedges, ground ice, ice of the intrusive-segregated seasonal mound, and segregated ice of Eastern Chukotka near Koolen Lake, the settlement of Lavrentiya on the ...Chul’kheveem River, the settlement of Lorino, and the city of Anadyr on the Onemen Bay coast was studied. The comparison of isotopic diagrams showed that the variations in δ
18
O of the Holocene ice wedges of Eastern Chukotka did not exceed 2‰, which indicates the insignificant variability of climatic winter conditions in the late Holocene. The long-term mean-January temperature values varied less than 3°C according to calculations from the equations of interrelation between air temperature and the isotopic composition of the wedges.
Stable isotope composition of syngenetic and epigenetic ice wedges, radiocarbon age, and pollen spectra of the surrounding deposits were studied during long term investigations at the “Belyi Klyuch” ...site on the first (6–8 m height) terrace of the Chara River (720 m.a.s.l.) in northern Transbaikalia to assess climatic conditions during ice-wedge formation. It was revealed that Holocene ice wedges had been formed from 10 to 7.5 ka 14C BP. The isotope composition (δ18О, δ2H) of relict ice wedges is the lightest and amounts −23‰ and −185‰, correspondingly. The isotopic compositions of ice lenses from sandy loam above ice wedges are −15.7‰ and −133‰; of small ice wedge in peat and sand are −15.3‰ and −117.9‰, accordingly.
Interpretation of the ice wedge isotope composition has yielded that mean winter temperatures during cold stages of Holocene optimum were lower than today, during warm stages they were close to modern ones. During the coldest stages of Holocene optimum the total annual freezing index varied from −5100 to −5700 °C degree days, i.e. 300–600 °C degree days colder than during extremely severe modern winters. The total annual thawing index varied from 1300 to 1800 °C degree days, which was slightly higher than modern ones.
Display omitted
•Ice wedges on the first terrace formed between 10 and 7.5 14C ka BP.•Early Holocene climate signals from stable-isotope composition of ice wedge and pollen.•Total annual freezing index colder than extremely severe modern winters.•Total annual thawing index slightly higher and only occasionally fractionally lower, than modern ones.
Syngenetic ice wedges have been investigated on Ayon Island. Their isotope composition and the geochemical characteristics of both ice wedges and enclosing sediments have been obtained; four ...ice-wedge stages have been distinguished. Paleo temperature reconstructions for Ayon Island and adjacent territories of northern Chukotka have been obtained based of these results. Almost identical trends in the distribution of ice-wedge isotope characteristics in the Arctic islands and in the lower reaches of the Kolyma River were observed, as well as differences in the magnitude of isotope oscillations during the transition from the Late Pleistocene to the Holocene compared to ice wedges of the Lower Kolyma region.
PDF
