Nadine A. Budantseva

OXYGEN STABLE ISOTOPE VARIATION IN LATE HOLOCENE ICE WEDGES IN YAMAL PENINSULA AND SVALBARD

The stable oxygen isotope composition of Late Holocene syngenetic ice wedges from the Erkutayakha River valley in the Yamal Peninsula and from the Adventdalen valley in Svalbard was studied. It was demonstrated that the studied ice wedges located 2000 km apart were formed during the last 2-3.5 ka and continue to grow at present. Variations of δ18O values of the ice of both ice wedges do not exceed 2-3.5‰. Based on the oxygen isotope variations is has been calculated that mean winter air temperatures did not change by more than 3oC during the Late Holocene.

EVALUATION OF GLACIER MELT CONTRIBUTION TO RUNOFF IN THE NORTH CAUCASUS ALPINE CATCHMENTS USING ISOTOPIC METHODS AND ENERGY BALANCE MODELING

Frequency and intensity of river floods rise observed in the North Caucasus during last decades is considered to be driven by recent climate change. In order to predict possible future trends in extreme hydrological events in the context of climate change, it is essential to estimate the contribution of different feed sources in complicated flow-forming processes in the alpine part of the North Caucasus. A study was carried out for the Djankuat River basin, the representative for the North Caucasus system. Simultaneous measurements of electrical conductivity, isotopic and ion balance equations, and energy balance modeling of ice and snow melt were used to evaluate the contribution of different sources and processes in the Djankuat River runoff regime formation. A forecast of possible future changes in the Djankuat glacier melting regime according to the predicted climate changes was done.

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

High mountain areas provide water resources for a large share of the world’s population. The ongoing deglaciation of these areas is resulting in great instability of mountainous headwater regions, which could significantly affect water supply and intensify dangerous hydrological processes.The hydrological processes in mountains are still poorly understood due to the complexity of the natural conditions, great spatial variation and a lack of observation. A knowledge of flow-forming processes in alpine areas is essential to predict future possible trends in hydrological conditions and to calculate river runoff characteristics. The goal of this study is to gain detailed field data on various components of natural hydrological processes in the alpine areas of the North Caucasus and Central Tien Shan, and to investigate the possibility that the isotopic method can reveal important regularities of river flow formation in these regions. The study is based on field observations in representative alpine river basins in the North Caucasus (the Dzhankuat river basin) and the Central Tien Shan (the Chon-Kyzyl-Suu river basin) during 2013–2015. A mixing-model approach was used to conduct river hydrograph separation. Isotope methods were used to estimate the contribution of different nourishment sources in total runoff and its regime. d18О, dD and mineralization were used as indicators. Two equation systems for the study sites were derived: in terms of water routing and runoff genesis. The Dzhankuat and Chon-Kyzyl-Suu river hydrographs were separated into 4 components: liquid precipitation/meltwaters, surface routed/subsurface routed waters.

14C age, stable isotope composition and pollen analysis of massive ice, Bovanenkovo gas field Central Yamal Peninsula

The origin of the massive ice is important for understanding the Quaternary history of the Yamal region and to predict the occurrence of massive ice, which is important for gas exploration and the development of infrastructure. Massive ice bodies occur in the Bovanenkovo gas field area within sediments such as layers, laccoliths, rods and lenses. Maximal thickness of the tabular ice is 28,5 m; mean thickness is about 8 m. Deposits of the third terrace underlying and overlapping the tabular ice had been formed from 25 ka BP to 20 ka BP, according to 14C dates. Oxygen-isotope values (δ18О) of massive ices are ranged from 12, 49‰ up to -22, 95‰. Deuterium (δD) values vary from -91, 7‰ up to -177, 1‰. Deuterium excess (dexc) changes from 3, 4 to 10, 6‰. Both homogenous and contrast distribution δ18О and (δD) vs. depths in massive ice bodies evidences the segregated and/or infiltrated-segregated manner of ice formation. Pollen, spores and algae spectra from ice are similar to pollen characteristics of modern lacustrine and coastal floodplain sediments in the area. The ingression of cold seawaters on a coastal flood plain caused freezing and ice segregation, with the formation of extensive ice layers under the large but shallow lakes. As a result, syngenetic and genetically heterogeneous ice, such as: segregated, infiltrated-segregated, lake bottom congelation ice etc. was formed.

OXYGEN AND HYDROGEN ISOTOPE VARIATIONS IN A RECENTLY FORMED MASSIVE ICE AT THE MOUTH OF THE AKKANI RIVER, EASTERN CHUKOTKA

The object of this study is a recently (or in the Holocene) formed thick (up 2.7xa0m in height) buried massive ice body, exposed in 2xa0km South-East from the mouth of the river Akkani in the North-East of Chukotka in the vicinity of the settlement Lavrentiya. The structural-textural characteristics of ice and enclosing deposits are considered. It is shown that the overlying layers of sediments are loams with a slab structure and vertical-layer medium and thin-chill cryogenic structure and ice sockets. The ice of the body is very pure and transparent, visible to a depth of 0.5xa0m. There are some inclusions found in massive ice: sand and loams presented in forms of thin interlayers of particles or granules. The ice is full of bubbles. The main method of the research was the analysis of isotopes of oxygen and hydrogen within the stratified ice body, and also relationships between them as well as ratios between the deuterium excess and δ 2 Н. The thick and relatively contemporary massive ice layer buried under a layer of proluvial sediments had been found for the first time, and together with this, the isotope variations of the buried ice (δ 2 Н and δ 18 O) were determined. The mean values of δ 18 О and δ 2 H in the ice are rather stable and equal to −17.1 and −128.3‰, respectively. These isotope characteristics may be used for cryogenic reconstructions of massive ice formations widely distributed in the late Quaternary deposits in Eastern Chukotka.

Djankuat Glacier Station in the North Caucasus, Russia: A Database of complex glaciological, hydrological, meteorological observations and stable isotopes sampling results during 2007-2017

The study presents a dataset on long-term complex glaciological, hydrological, meteorological observations and isotopes sampling in an extremely underreported alpine zone of the North Caucasus. The Djankuat research basin is of 9.1 km2, situated on elevations between 2500 – 4000 m, and covered with glaciers by 30%. The largest in the basin, the Djankuat 20 glacier, was chosen as representative of the central North Caucasus during the International Hydrological Decade and is one of 30 ‘reference’ glaciers in the world which have annual mass balance series longer than 50 years (Zemp et al., 2009). The dataset reported here covers 2007–2017 and contains the result of yearly measurements of snow depth and density; dynamics of snow and ice melting; measurements of water runoff, conductivity, turbidity, temperature, δ18O, δD at the main gauging station (844 samples in sum) with a one-hour or several-hours’ time step depending on the parameter; data on δ18O and δ2H 25 sampling of liquid precipitation, snow, ice, firn, groundwater in different parts of the watershed taken regularly in time during melting season (485 samples in sum); precipitation amount, air temperature, relative humidity, shortwave incoming and reflected radiation, longwave downward and upward radiation, atmospheric pressure, wind speed and direction – measured at several automatic weather stations within the basin with 15 min to one-hour step; gradient meteorological measurements to estimate turbulent fluxes of heat and moisture, measuring three components of wind speed at a frequency of 10 hertz to estimate 30 the impulse of turbulent fluxes of sensible and latent heat over the glacier surface by the eddy covariance method. All the observations were done during the ablation period (June–September) and were interrupted in winter. The dataset was published on knb.ecoinformatics.org long-term repository (doi:10.1594/PANGAEA.894807) and will be further updated. The dataset can be useful for developing and verifying hydrological, glaciological and meteorological models for high elevation territories,

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.

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.n Yu.K. VASIL’CHUK

New data on variations of stable isotopes in the pingo ice core in the southern part of the Tazovsky Peninsula

The aim of this work is to obtain the vertical isotopic profile of the thick Pestsovoe pingo ice core in the southern part of the Tazovsky Peninsula, to determine the oxygen and hydrogen isotopic composition of the ice, and to reveal its formation conditions. Two trends were identified for the isotopic profile of the pingo ice: an insignificant increase of the δ18O (~1.5‰) and δD (~9‰) values at depths of 12–15 m and a gradual decrease of isotopic values by 3.8 and 23‰ for δ18O and δD, respectively, at a depth of 15–26 m. The formation of the pingo ice core in the semiclosed system resulted in fractionation of the isotopic composition of oxygen and hydrogen by more than 4 and 20‰, respectively.