Vol. XXVIII, No. 1 (January – February 2024)
Full issue:   EC_1_2024_eng_opt.pdf

CONTENTS

GEOCRYOLOGICAL MONITORING AND FORECAST

  • Konstantinov P.Ya., Fedorov A.N., Argunov R.N., Efremov P.V., Kadota T., Shirakawa T. Temperature changes in permafrost and glacier ice in the high-mountain part of the Suntar-Khayata Ridge (northeastern Russia) for the period 1957–2017
    Abstract
    In 1957–1959, according to the program of the 3rd International Geophysical Year, the temperature of rocks (to a depth of 20 m) and glacier ice (to a depth of 45 m) was measured in the area of a high-mountain weather station (glacier No. 31) in the central part pf the Suntar-Khayata Ridge (northeastern Russia). In 2012–2017, the Russian–Japanese expedition carried out new measurements of the temperature of rocks and glacier ice at the same places. A comparison of the data on the mean monthly temperatures of glacier ice at a depth of 10 m in 1958 and 2012 attests to their rise by 1.0–1.6°С. As there was no possibility to perform direct measurements of rock temperature at a depth of 20 m in 2012–2017, we used an indirect method to estimate it at the depth of zero annual amplitude. According to our estimate, in the past 60 years, it could have increased by up to 1.6°C. Regime studies of the dynamics of seasonal thawing were carried out at four experimental plots; of the dynamics of freezing of the seasonally thawed layer, at one plot.
     Keywords
    climate change, permafrost, glaciers, ground temperature, seasonal thaw, seasonal freezing

  • Rivkin F.M., Buldovich S.N. Regularities of new formation of frozen ground against the background of a positive climatic trend
    Abstract
    Regularities of the modern development of frozen ground near the southern boundary of permafrost against the background of a positive climate trend are considered. Criteria for the potential formation of permafrost in response to climate warming are established. Results of modeling and quantitative assessment of the newly formed permafrost caused by thaw subsidence and subsequent transformation of landforms are given with due account for soil drainage and warming effect of the snow cover.
     Keywords
    permafrost, thawing of frozen ground, freezing of thawed ground, changes in permafrost conditions, frozen ground thaw subsidence, relief inversion

CRYOLITHOGENESIS

  • Levochkina O.V., Tumskoy V.E., Dudarev O.V. Sedimentological analysis of bottom sediments of the Ivashkina Lagoon (Bykovsky Peninsula)
    Abstract
    The results of sedimentological analysis of bottom sediments of the Ivashkina Lagoon on the southern coast of Bykovsky Peninsula (southeast of the Laptev Sea) are presented. Core samples from boreholes drilled in the ancient thermokarst depression now occupied by the lagoon have been analyzed. The use of grain-size distribution data and Passega C–Md diagrams makes it possible to refine the genetic interpretation of the sediments obtained from field descriptions. The Holocene lacustrine–lagoon and taberal sediments and the underlying Middle and Late Pleistocene alluvial sediments have been identified, and their grain-size characteristics have been determined. We have further reconstructed the sequence of sedimentation events in the course of transformation of a thermokarst lake into a marine lagoon.
     Keywords
    thermokarst lagoons, Laptev Sea, lake sediments, lagoon sediments, sedimentological analysis, Passega diagram

  • Lupachev A.V., Tikhonravova Ya.V., Danilov P.P., Zanina O.G., Cheprasov M.Yu., Novgorodov G.P. Paleoecological indicators of the conditions of permafrost development in the area of Batagay retrogressive thaw slump
    Abstract
    The morphology and properties of frozen strata were studied in the area of the largest retrogressive thermal thaw slump Batagay (Yakutia). A presumably continuous stratigraphic sequence of permafrost sediments accumulated during the Middle and Late Pleistocene (~700–11 ka) and was partially transformed during the Holocene. Based on paleopedological, paleontological, and geocryological data, new suggestions have been made regarding the historical development of the soil-vegetation cover and late glacial fauna in the Yana Plateau region. Two extensive and relatively warm climatic periods favoring the formation of developed soil-vegetation cover have been identified: the first one belongs to MIS 15–17 (600–700 ka) or (depending on the dating method) to MIS 7e (230–250 ka); the second one is more certainly dates back to MIS 5e (110–130 ka).
     Keywords
    cryogenic ecosystems, permafrost-affected soils, Yakutia, paleoreconstruction, phytoliths

    GASES AND GAS HYDRATES IN THE EARTH’S CRYOSPHERE

  • Oblogov G.E., Vasiliev A.A., Orekhov P.T., Savvichev A.S., Streletskaya I.D. Pockmarks and methane content in lake sediments of the Yamal Peninsula
    Abstract
    The paper presents the results of studying the appearance and sizes of pockmarks in lakes of three bioclimatic zones of Yamal: northern (arctic), typical, and southern tundra. The diameter of pockmarks in the lakes increases from 1.9 m in the northern tundra to 7.7 m in the southern shrub tundra. Pockmarks occupy from 0.5 to 4.3% of the shallow-water lake area. The content of methane in lake sediments is two or more times higher than in the sediments of the active and transient layers of dominant landscapes. In the typical tundra zone, the methane content in lake sediments is usually about 7 mL/kg, but in some cases it can reach 18 mL/kg and more. Probably, the lakes with the high methane content in bottom sediments are the lakes, where gas emissions can occur and pockmarks can form. After drainage (drying) of the lakes, lake basins (khasyreys) are subjected to freezing, and the cryogenic structure of lake sediments is formed. Eight–ten years after drying, succession changes in the former lake bottoms continue, and the formation of the transient layer is not yet completed.
     Keywords
    permafrost, pockmarks, lakes, Yamal, methane content in sediments

SNOW COVER AND GLACIERS

CHRONICLE