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
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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 dating of microinclusions of organic material in a sample from the upper part of the Pleistocene syngenetic ice wedge, exposed in an outcrop of the Vilyui yedoma, located in the north of Yakutia, ...near the village of Kysyl-Syr (coordinates: 63°53′19″ N, 122°46′09″ E, height above sea level 100 m), was performed using accelerator mass spectrometry (AMS). The dated fragment of the ice wedge was formed about 22.5–22.3 cal. ka BP (18.46 ka radiocarbon years BP). Based on the isotopic data, the mean January air temperature of the Late Pleistocene was calculated from 22 to 23 cal. ka BP for the Vilyui section. It is shown that the mean January air paleotemperature during this period in the basin of the Vilyui River varied from –44 to –42°C.
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 δ
18
O (~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 δ
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O 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.
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.
This paper reports on the oxygen isotope composition of the Late Pleistocene and Holocene syngenetic ice wedges, which were exposed at Mamontova Gora and Syrdakh Lake, the Accelerator Mass ...Spectrometry dating, and the reconstruction of the winter air temperatures during ice wedge formation. Organic microinclusions from the ice wedges were directly dated, which allowed us to establish seven dates ranging from 13 to 19 ka BP. The age of the ice wedges is shown to be younger than 20 ka, but older than 10 ka BP. In the area of Mamontova Gora, δ
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O is in the range of –24.7 to –30.9‰ for the Late Pleistocene ice wedges, and of –23.2 to –25.9‰ for the Holocene ice wedges. In the area of Syrdakh Lake, δ
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O ranges from –29.2 to –32.5‰. At the Mamontova Gora site, the average winter air temperatures, which were reconstructed from the isotope data, ranged from –28 to –31°C during most of the period when the Late Pleistocene ice wedges were formed; the January temperature was –42°C, –46°C. At the Syrdakh Lake site, the Late Pleistocene winter conditions were more severe: the average winter air temperature ranged from –30 to –32°C, and the average January air temperature was –44, –48°C. In the Holocene, the average winter air temperatures were higher and ranged from –24 to –28°C, while the average January temperatures ranged from –36 to –42°C.
The main aim of this work is to study the oxygen isotope composition of Late Pleistocene syngenetic repeated ice wedges and to obtain a high-resolution isotope diagram based on detailed sampling of ...the Seyakha yedoma section in the sequence of the Late Pleistocene third lagoonal-marine terrace near the mouth of the Seyakha (Zelenaya) River, on the shore of the Gulf of Ob. According to three new radiocarbon ages (25.2 to 23.3 ka BP) from absolute heights of +2 to +5 m and also ages obtained earlier (17.3 ka BP from +18.8 m; 11.6 ka BP from +21.2 m), the approximate age of this ice wedge ranges from 23 to 15–18 ka. The values of δ
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О in the upper fragment of the ice wedge vary from –25.75 to –23.15‰. The amplitude of horizontal variations in δ
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О at +15.2 m height is 1.49‰ (–23.41 to –24.9‰). The lower fragment of the ice wedge at +6 m height is characterized by a broader variation range of δ
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О compared to the upper one: δ
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О varies in the horizontal direction from –23.41 to –26.63‰. The detalization step of the oxygen isotope diagram obtained is 80–100 years. The mean January temperature in the period 23–15 (18) ka BP ranged from –35 to –39°C.
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