Accelerator mass spectrometry dating of organic microinclusions was performed on eight samples from the lower part of the thick Pleistocene syngenetic ice wedges exposed in the Batagay mega-slump in ...northern Yakutia, the upper reaches of the Yana River (67.58° N, 134.77° E). Radiocarbon dating suggests that ice wedge growth took place between 38 120 and 45 570
14
C BP (42.1–49 cal ka BP). The Late Pleistocene mean January air temperatures from 42 to 49 cal ka BP have been reconstructed from the isotope data for the Batagay section and a number of reference sections in northwestern Yakutia. The lowest mean January air temperature of –51°С for this period was in Batagaika, whereas in the areas located 500–600 km to the north, it was 5–7°C higher. This is accounted for by the influence of the Yakutian anticyclone in winter during the Late Pleistocene from 42 to 49 cal ka BP, which was as pronounced at that time as it is now.
The content of polycyclic aromatic hydrocarbons (PAHs) and carbon isotope composition in the peat of a palsa near Eletsky settlement, Vorkuta urban district, Komi Republic are analyzed. The carbon ...isotope composition of peat varies from –28.05 to –30.05‰ (average –29.15‰). The total PAH content varies from 11 to 360 ppb, with an average of 63 ppb and a median value of 34 ppb. Heavy compounds, such as benzo(
a
)anthracene and benzofluoranthenes, are prevalent among PAHs. The presence of PAHs in the peat is determined by three main factors: technogenic impact, wildfires, and biogeochemical soil processes. The prevalence of benzo(
a
)anthracene in the upper part of the palsa down to the bottom of the active layer suggests an anthropogenic impact (the influence of transport and domestic fuel combustion). The share of benzo(
a
)anthracene decreases with depth, while the share of benzofluoranthenes increases. Two sharp peaks of PAH content (260 and 360 ppb) are observed; they coincide with a local increase of carbon isotope values, most likely resulting from wildfires. The minimums in PAH content are presumably determined by the biogeochemical factor and the input of polyarenes generated by decomposition of plant residues. Carbon isotope composition of peat mainly reflects the isotope composition of vegetation, the degree of peat moistening, and the influence of pyrogenic factor.
For the first time, AMS radiocarbon dating was used to date microinclusions of organic material extracted directly from Holocene syngenetic ice wedges in the Noprthern European part of Russia, on the ...coast of Baydarata Bay near the village of Yarynskaya, 500 m south of the mouth of the Ngarka-Tambyakha River (68°51′20.27″ N, 66°52′6.51″ E). Dated ice wedges formed about 6.4, 5.0, and 1.9 ka BP. According to isotope oxygen data, the average January air paleotemperature in the Middle and Late Holocene on the coast of Baydarata Bay was calculated. It is shown that the average January air temperature during this period here varied from about −20 to −25°C. However, during milder winters it could have been about −18°C.
This paper reports on the nature and history of the mineral-rich frost heave mounds—lithalsas—developed on the first terrace of the Sentsa River in Okinsky District of Buryatia. An ice core of the ...lithalsa was exposed by drilling of a 20-m borehole. The most typical feature of the isotopic diagrams, which we obtained for the ice core, is their cyclical pattern illustrating isotope minima at depths of about 3–5 m, 9–12 m, and 18–21 m, separated by two distinct isotope maxima. Most likely, this demonstrates the cyclicity of the triple flooding of the growing frost heave mound and the subsequent active evaporation of lake-march waters, which are the main source of moisture for the lithalsa ice core. Based on the detailed radiocarbon dating of organic material from the upper horizons of the highest and surrounding lithalsas, we determined the time of their formation. Organic material in drained frost-susceptible soils was intensely accumulated during the period from 0.5 to 0.2 ka BP. This is the time of the beginning of the formation of permafrost, active ice-formation, and the associated frost heave and lithalsa growth. The age of at least three of four mounds studied is not older than 200 years, it coincides with the cooling at the beginning of the 19th century.
The stable oxygen and hydrogen isotope composition of Late Pleistocene syngenetic ice wedges of Batagai yedoma are studied, and detailed isotope diagrams are obtained. The reconstructed mean January ...paleotemperature is lower than –51°С, which completely confirms the validity of the paleotemperature maps made earlier for the period of 30–25 ka BP where the location of the Batagai section within the isotherm of –48°C.
Microinclusions of organic matter were dated using acceleration mass spectrometry in seven samples from the upper part of the thick Pleistocene syngenetic ice wedge exposed in the outcrop of the ...Batagay yedoma located in northern Yakutia along the upper Yana River (67.58° N, 134.77° E). The dated fragment veins were formed within 22 760–29 910 radiocarbon years BP (or 27.1–33.8 cal BP) ago. Using detailed isotope data, the January average air temperature in the Late Pleistocene (27–30 cal BP) was calculated for the Batagay section along with a series of reference sections in northwestern Yakutia. It was shown that the minimum January average air temperature (–51°C) was characteristic at that time for the area of the Batagaika crater, with values 4–5°C higher in areas 500–600 km further north. This effect was caused by the occurrence of the Yakutia anticyclone in winter during the Late Pleistocene, which was just as pronounced as that at the present time.
The carbon isotope signatures and the content of polycyclic aromatic hydrocarbons (PAHs) in the pedogenic material of inclusions in ice wedges of the Batagay yedoma (Yakutia) are studied. The mean ...concentration of 11 PAHs is 170 ppb (minimum, 7 ppb and maximum, 430 ppb) and the mean δ
13
С value in soil lipids is –29‰ (minimum, –31.1‰ and maximum, –26.2‰). The prevalent polyarenes in associations are naphthalene homologs and phenanthrene. Trace amounts of heavy PAHs, including benzo
a
pyrene (an indicator of pyrogenic processes), are also detectable. The PAH contents and δ
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С values in ice wedges show the trend of a decrease with depth. The δ
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С values and PAH content suggest a pedogenic origin of the deposit: therefore, PAHs originate from plant residues and wildfires. The observed trend of changes in the concentrations of polyarenes along the ice wedge may be associated with the changes in landscapes in the Late Pleistocene.
The results of studies of variations of δ
18
O values in river water in Crimea Peninsula in January–February 2015–2017 are given. The variation range of δ
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О in river water over the three years of ...studies never exceeded 3‰. A tendency toward an increase in δ
18
О in the water of the Salgir, Kacha, Al’ma, Bel’bek, Biyuk-Karasu from their sources to mouths was identified and explained by a decrease in evaporation in the mouth areas of the rivers relative to their sources and upper reaches, and the inflow of isotopically light precipitation (rain and snow) into the rivers in their upper reaches. The values of δ
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О in waters of the rivers with regulated stream were found to increase under the effect of the Simferopol Reservoir on the Salgir River and the Izobil’nenskoe Reservoir on the Ulu-Zen’ River. The values of δ
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О in the upper reaches of the large rivers of Kacha and Bel’bek (the northwestern slope of the Crimean Mountains) vary from −8.7 to −9.7‰, except for the rivers of Al’ma (−7.7‰) and Kokozka (−10.2‰) because of the different shares of groundwater in the recharge of these rivers.
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