Yu. K. Vasil’chuk

Water isotopic-geochemical composition in the Trekhtsvetnoe meromictic lake on the White Sea coast

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 δ18O varying from–12 to–11.1‰; (2) 1.0–3.0 m: zone with transitional properties with δ18O varying from–11.1 to–5.5‰; (3) 3.0–7.6 m: monimolimnion zone with highest values of δ18O—from–5.5 to–4.7‰.

Isotopic and palynological compositions of a massive ice in the Mordyyakha River, Central Yamal Peninsula

The investigation objective is to study a new mas� sive ice in the Mordyyakha River valley (the Central Yamal Region), to determine the contents of stable oxygen and hydrogen isotopes in the ice, and to study pollen spectrum remains. These data are used to study the ice formation conditions and to prove that massive ice are heterogeneous and originated from lake waters. The investigated body is similar to those studied in dif� ferent Yamal regions such as Erkutayakha River valley [1], Bovanenkovo field [2], and the lower Yuribei River [3–5].

Local pollen spectra as a new criterion for nonglacial origin of massive ice

985 The stratal ice deposits represent one of the most dangerous cryogenic phenomena, which influences the economic activity in areas with permafrost devel opment. This is particularly true in connection with intense development of Arctic areas, which required extensive studies of stratal ice deposits and their gene sis. Such studies were conducted in the Shpindler Cape area [1], on the southern coast of the Baidar atskaya Estuary [2], near the Marresale [3] and Kha rasavei [4] settlements, in the western Yamal Penin sula, in the Bovanenkovo [5] area, in the Yuribei River valley [6], in the Neito Lake area [7] in the central part of the Yamal Peninsula, and in the Erkutayakh River valley [8]. Genetic interpretation of all these ice deposits is uncertain despite the relatively high degree of knowl edge about them, repeated visits to them, the cryos tratigraphic descriptions, and substantially compre hensive analytical studies [9]. Moreover, the same structural and compositional features are frequently interpreted in different ways [10]. As a whole, all the interpretation variants are limited to the following dilemma: this is either intrastratal or buried glacial ice. The purpose of this work is to demonstrate new possibilities of palynological analysis, primarily using local components of pollen spectra for clarifying the genesis of stratal ice, which allow the ice of buried gla ciers to be discerned from all other types of stratal ice since local pollen and spores cannot accumulate in glaciers of Arctic domes. The long term palynological studies of ground deposit forming ice made it possible to define several characteristic features of their spectra. In short, these characteristic feature may be formulated in the follow ing way: (1) pollen and spores are present in practically all varieties of deposit forming ground ice and their concentration ranges within limits of 50 to 1500 spec imens per 1 kg of ice or in 1 l of thawed water; (2) most stratal ice deposits contain spectra with the composi tion close to that of subfossil tundra pollen spectra with the dominant dwarf birch and Ericaceae pollen and Bryales spores; (3) stratal ice deposits frequently contain pre Quaternary palynomorphs of Cenozoic, Mesozoic, and Paleozoic ages reworked from older sediments; (4) most of the studied stratal ice deposits enclose pollen of aquatic plants such as Potamogeton, Sparganium, Typha as well as Equisetales spores and remains of freshwater diatoms and Chlorophycaceae algae.

Oxygen Isotope and Deuterium Indication of the Origin and 14C Age of the Massive Ice, Bovanenkovo, Central Yamal Peninsula

The conditions and forming time of massive ice were specified (Bovanenkovo gas condensate field, Central Yamal). Here, massive ice lies as stratums, laccoliths, stocks, and lenses. Three thousand boreholes 10–100 m in depth were analyzed. In 260 of them massive ice was broached. The ice foot is situated from 1 to 57 m deep. The maximal thickness of ice broached with boreholes came to 28.5 m; on average, it was about 8 m. The extension of massive ice is sometimes more than 2000 m, and its area is quite often more than 10 km2. According to the radiocarbon method, loams of the third terrace, containing and overlapping ice deposits, were formed from 25 000 to 20 000 years ago or somewhat later. These strongly peat loams containing massive ice formed either in shallow sea conditions or during periodical draining conditions of beaches or low laida, where organic matter appeared due to erosion and deposition and accumulated during draining and overgrowing of drains. In more inclement conditions than at present, loam deposits were frozen immediately, forming massive ice, which occupied the barely water-saturated layers. The oxygen isotope composition (δ18O) of massive ice samples varied from −12.49‰ (here and further, relative to SMOW) to −22.95‰. The deuterium concentration (δD) varied from −91.7 to −177.1‰. Deuterium kurtosis (dexc) varied from 3.4 to 10.6‰. In one seam outcrop, the content of stable isotopes varied significantly. Here, at a depth of 0.2–0.8 m, the δ18O content varied by more than 10‰ (from −12.49 to −22.75), and the δD content, from −91.7 to −171.9‰. Such variations testify about ice extraction upon freezing of water-saturated grounds in a closed system. According to palynological analysis of ice stratums, numerous remains of unicellular green algae and diatoms were revealed. It is possible that this is evidence of the existence of a fresh well, which was a source of water, feeding the layer. Most probably these were near-bottom silt waters of a large lake or desalted bay, which were frozen syngenetically. This accentuates the new type of massive ice, syncriogenic segregative ice, which probably formed 25 000–20 000 yr BP.

Oxygen isotope and deuterium composition of snow cover on the profile of Western Siberia from Tomsk to the Gulf of Ob

The purpose of this work is to study the variability of the isotope composition (δ18О, δD, dexc) of the snow cover on a long transect of Western Siberia from the southern taiga to the tundra. The study of the snow cover is of paleogeographic, paleogeocryological, and paleohydrological value. The snow cover of western Siberia was sampled on a broadly NS transzonal profile from the environs of Tomsk (southern taiga zone) to the eastern coast of the Gulf of Ob (tundra zone) from February 19 to March 4, 2014. Snow samples were collected at 31 sites. Most of the samples represented by fresh snow, i.e., snow that had fallen a day before the moment of sampling were collected in two areas. In the area of Yamburg, the snow specimens collected from the surface are most probably settled snow of different ages. The values of δ18О in the snow from Tomsk to Yamburg varied from–21.89 to–32.82‰, and the values of δD, from–163.3 to–261.2‰. The value of deuterium excess was in the range of 4.06–19.53‰.

Hydrograph separation of the Dzhankuat River, North Caucasus, with the use of isotope methods

The formation of snowmelt runoff from the Dzhankuat glacier has been considered and the hydrograph of the Dzhankuat R. has been separated with the use of isotope and ionic balance. Isotope variations of runoff at the outlet section of the Dzhankuat R. have been studied for two ablation seasons of 2013 and 2014. The separation of 2014 hydrograph was based on δ18O and mineralization values obtained for various sources of Dzhankuat R. recharge: precipitation, snow of different seasons, firn, ice, and groundwater. The isotopic separation of the hydrograph has shown that, in June, a considerable portion (15–20%) of Dzhankuat R. total runoff is due to the melting snow cover that has formed during spring snowfalls. In June, the proportion of this component in the total daily runoff can reach 36%. The contribution of the runoff originating from winter-snow melting varies from 20% in the early to 50% in the late June. In August and September, the share of groundwater varies from 30 to 100%; the share of precipitation, from 0 to 30% (on the average for the period, 6%); and the share of water from melting firn and ice, from 0 to 70% (on the average, 38.6%).

Oxygen Isotope Composition of Holocene Ice Wedges of Eastern Chukotka

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 δ18O 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.

Isotopic Indications of Meromixis in Separated Lakes on the White Sea Coast

Studies of lakes at different stages of separation from the sea have been carried out on the northwestern coast of Kandalaksha Gulf of the White Sea. At the end of the winter period, from March 16 to 29, 2013, the lakes Kislo–Sladkoe, Trekhtzvetnoe, Nizhnee Ershovskoe, Ermolinskaya Bay and snow near the pier of Pertsov White Sea Biological Station of Moscow State University (WSBS MSU) were studied. The isotope characteristics of the water of lakes, ice and snow, the distribution of salinity, temperature, and hydrogen sulfide content were studied.

Concentration of 18O in precipitation over Moscow in 2014

The series of δ18O values is presented for all precipitation events in Moscow in 2014. Precipitation samples were taken at the observation site of the Meteorological Observatory of Lomonosov Moscow State University (MSU MO), and the isotopic analysis was carried out in the isotopic laboratory of the Department of Geography of MSU. The concentration of stable 18O in precipitation over Moscow in 2014 varied from -0.09 to -26.29‰. The maximum amplitudes of δ18O were registered in March-April and October. The pronounced interrelation was revealed between the oxygen isotopic composition of precipitation and surface air temperature (the correlation coefficient is 0.85). The computation of back trajectories of air masses and the analysis of weather charts demonstrated that the most isotopically light precipitation is typical of relatively cold air masses slowly moving over the continent during the last five days before precipitation. In this case, the ongoing condensation leads to the progressive isotopic depletion of precipitation (more and more isotope-depleted precipitation is registered). On the contrary, fast air transport from the middle and even from high latitudes of the Atlantic Ocean leads to the relatively constant of δ18O values of precipitation.

Erratum to: Using isotope methods to study alpine headwater regions in the Northern Caucasus and Tien Shan

The original version of this article unfortunately contained a mistake. The spelling of the Yu.K. VASILCHUK’s name was incorrect. The correct name is given below. Yu.K. VASIL’CHUK