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.
Research data on the isotopic composition of carbon in soil lipids in the Zhirnovskoe and Bakhmet’evskoe oil and gas fields in the Medveditsa River basin, Volgograd oblast, Russia, are analyzed. Oil ...and atmospheric soil pollution is recorded. The variations in the isotopic composition are determined by both anthropogenic factors and the diversity of natural conditions. The isotopic composition of carbon in the lipids of the interfluvial soils (chernozems) is heavier (–26.9 to –29.2‰) than that in the alluvial soils (–29.4 to –31.3‰) because of the differences in the moistening and temperature conditions. Oil pollution appears as a lighter isotopic composition (–29.3 to –29.8‰) since oil isotopic composition is in general somewhat lighter (–28.4 to –30.6‰) as compared with unpolluted soils. Urban and transport infrastructure makes the isotopic composition of atmospheric CO
2
lighter, thereby influencing the δ
13
С values of plants and soils.
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 vertical isotopic profile of the ice core of a Messoyakha-1 bulgunniakh (pingo)—was obtained. The pingo is situated at 68°30′32″ N, 79°59′53″ E, in the southern part of the Gydan Peninsula within ...the Middle Messoyakha swell. No significant variations were registered in the isotopic composition of the pingo ice core: δ
18
О varied from –14.98 to –16.60‰ and δ
2
Н varied from –117.9 to –122.8 ‰. This small range of values probably resulted from intense heaving and rather rapid formation of the pingo. Based on the features of the pingo, it can be assumed that initially there was a lake of 0.5 km length and 0.3 km width at this site. Then, the water drained into a nearby river, the lake began to dry out, and the khasyrey (alas), which occupies most of the former lake area, was formed. The pingo itself arose during the freezing of the alas under its gradual drying out.
The aim of the work was to perform paleotemperature reconstructions for the Late Pleistocene and Holocene of Kotelny Island according to oxygen isotope analysis of syngenetic ice wedges. Variations ...of δ
18
O in the Late Pleistocene ice wedges formed on Kotelny Island are significant, exceeding 8‰ (from –30‰ to –22.9‰), while they are insignificant at –1.5‰ (from –23.1‰ to –21.6‰) for those in the Holocene. Reconstructions showed that the mean January temperature in the Late Pleistocene changed over 8 to 13°C. The mean annual temperature of frozen soils was about –19 or –20°C in the Late Pleistocene, and about –13 to –15°C in the Holocene, while the current temperature is about –14°C.
The purpose of this work is to study the variability of the isotope composition (δ
18
О, δD,
d
exc
) 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 δ
18
О 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‰.
This paper reports the results of the first study aimed at determination of the age of landslides on the southern slope of the Psekhako Ridge and northern slope of the Aibga Ridge (Western Caucasus) ...using radiocarbon dating of organic material incorporated into the landslide body.
Biotracers marking the geologic history and permafrost evolution in Central Yakutia, including Yedoma Ice Complex (IC) deposits, were identified in a multiproxy analysis of water chemistry, isotopic ...signatures, and microbial datasets. The key study sections were the Mamontova Gora and Syrdakh exposures, well covered in the literature. In the Mamontova Gora section, two distinct IC strata with massive ice wedges were described and sampled, the upper and lower IC strata, while previously published studies focused only on the lower IC horizon. Our results suggest that these two IC horizons differ in water origin of wedge ice and in their cryogenic evolution, evidenced by the differences in their chemistry, water isotopic signatures and the microbial community compositions. Microbial community similarity between ground ice and host deposits is shown to be a proxy for syngenetic deposition and freezing. High community similarity indicates syngenetic formation of ice wedges and host deposits of the lower IC horizon at the Mamontova Gora exposure. The upper IC horizon in this exposure has much lower similarity metrics between ice wedge and host sediments, and we suggest epigenetic ice wedge development in this stratum. We found a certain correspondence between the water origin and the degree of evaporative transformation in ice wedges and the microbial community composition, notably, the presence of
Chloroflexia
bacteria, represented by
Gitt-GS-136
and
KD4-96
classes. These bacteria are absent at the ice wedges of lower IC stratum at Mamontova Gora originating from snowmelt, but are abundant in the Syrdakh ice wedges, where the meltwater underwent evaporative isotopical fractionation. Minor evaporative transformation of water in the upper IC horizon of Mamontova Gora, whose ice wedges formed by meltwater that was additionally fractionated corresponds with moderate abundance of these classes in its bacterial community.
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