Geology

The aim of this study was to determine the contribution of snow and glacial ice to the river fluxes, and to identify the type of ice formation in the Tsambagarav massif (the northwestern part of Mongolia). The main method for this study was isotopic analysis of water samples. The isotopic separation showed that the shares of the main components in the total runoff differed for different rivers of the massif. Alongside with that, glacial meltwater prevailed in all the investigated fluxes. The share of snow and firn in the meltwater coming from the surface of the large valley glaciers in the middle of the ablation season in 2017 changed by only 10%—from 20% to 30%. Thus, further reduction of glaciation caused by global climate change could significantly affect the water balance of the study area. The isotopic composition of glacial ice proves that its alimentation primarily comes from precipitation during the transitional seasons. Superimposed ice is not the basis for nourishment of t...

This study aims to analyze the stable isotope composition of the snow cover of the Elbrus Mountain – the highest mountain in Europe. Snow sampled in the middle accumulation period in January 2017, February 2016, January 2001 and during snowmelt in July 1998 and August 2009. Snow sampled at the south slope of Mt. Elbrus at different elevations, and the total altitude range is approximately 1700 m. A significant altitude effect in fresh snow precipitation was determined in February 2001 with gradient –1.3‰ δ18O/100 m (–11.1‰ δ2 H /100 m) at 3100-3900 m a.s.l. and inverse altitude effect in February 2016 with gradient +1.04‰ δ18O /100 m (+8.7‰ δ2 H /100 m) at 3064-3836 m a.s.l. There is no obvious altitude effect of the δ2 H and δ18O values in snow at the Elbrus slope in 2017, except for the height range 2256-3716 m a.s.l., where altitudinal effect of δ18O values was roughly -0.32‰/100m. The δ18O values in the winter snowpack in some cases decrease with increasing altitude, but sometim...

Postglacial isostatic uplift of the coastal zone resulted in the formation of isolated lakes along the shores of White Sea developed into permanently stratified (meromictic) lakes. On the basis of monitoring the vertical distribution of selected water quality parameters including temperature, salinity, concentration of major ions, microbial activity, dissolved oxygen and hydrogen sulfide, seasonal changes in the structure of the stratified water column are explored and governing factors identified. Lake Trekhtzvetnoe has a strong vertical stratification with seasonal mixing being confined to the upper part of the water column (mixolimnion). Сhemical water composition in the mixolimnion reflects the influence of precipitation with the underlying chemocline being defined by sharp gradients of salinity, dissolved oxygen and hydrogen sulphide levels. We found strong stable isotope stratification of water column in winter-early spring seasons of 2013, 2015 and 2016 and in the early autum...

The formation conditions of the Bishuli thermomineral waters from the Crimean Plain were determined by a complex of isotopic methods. The absence of tritium (3H 0.1 TU) and considerable radiocarbon age ( = 28 3 ka) are in line with the light isotopic composition of the mineral water (18O = 13.4 and 2H = 96), which is strongly different from that of the recent precipitation, river water, and groundwater of the region (18O from 7.4 to 8.7 and 2H from 50 to 62). The formation of the mineral waters should be assigned to the Dnestr pluvial interstadial of the last glaciation, which reached the maximum in the region approximately 27 ka ago. The recharge zone is probably located on the northern slope of the Crimean Mountains (at a distance of ~60 km), which, together with the absence of tritium, indicates that the mineral waters are protected from an anthropogenic impact.