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2022064369 Bussière, Léa (CNRS, Environnements et Paleoenvironnements Oceaniques et Continentaux, Pessac, France); Schmutz, Myriam; Fortier, Richard; Lemieux, Jean-Michel and Dupuy, Alain. Near-surface geophysical imaging of a thermokarst pond in the discontinuous permafrost zone in Nunavik (Québec), Canada: Permafrost and Periglacial Processes, 33(4), p. 353-369, illus. incl. 2 tables, sketch map, 69 ref., December 2022.
In this study, high resolution ground-penetrating radar (GPR), electrical resistivity tomography (ERT), and spectral-induced polarization tomography (SIPT) were used to (i) delineate characteristic solifluction features, (ii) map the ice distribution, and (iii) assess subsurface water content and permeability in the surrounding rampart of a thermokarst pond in the discontinuous permafrost zone. The study site is located in the Tasiapik Valley near Umiujaq in Nunavik (Quebec), Canada, which benefits from decades of geological mapping, geophysical investigation, and monitoring of ground temperature and thaw subsidence, providing an extensive understanding of the cryohydrogeological context of the area. The results of geophysical investigation undertaken in this study were cross validated using core sampling, laboratory core analysis, and in situ ground temperature and water content monitoring. Based on this investigation, a conceptual model was derived and compared to the stratigraphy of cross-section described in literature in finer-grained context. Very good consistency was found from one in situ geophysical survey to another, as well as between the derived stratigraphic models and the ground truth. The combination of all the available data allowed the development of a detailed cryohydrogeological model across the studied thermokarst pond, which highlights the effect of lithology, topography, and land cover on the distribution and mobility of water in the ground. Abstract Copyright (2022), John Wiley & Sons, Ltd.
DOI: 10.1002/ppp.2166
2022064368 Daly, Seamus V. (University of Lethbridge, Department of Geography and Environment, Lethbridge, AB, Canada); Bonnaventure, Philip P. and Kochtitzky, Will. Influence of ecosystem and disturbance on near-surface permafrost distribution, Whatì, Northwest Territories, Canada: Permafrost and Periglacial Processes, 33(4), p. 339-352, illus. incl. 3 tables, sketch maps, 70 ref., December 2022.
For remote communities in the discontinuous permafrost zone, access to permafrost distribution maps for hazard assessment is limited and more general products are often inadequate for use in local-scale planning. In this study we apply established analytical methods to illustrate a time- and cost-efficient method for conducting community-scale permafrost mapping in the community of Whati, Northwest Territories, Canada. We ran a binary logistic regression (BLR) using a combination of field data, digital surface model-derived variables, and remotely sensed products. Independent variables included vegetation, topographic position index, and elevation bands. The dependent variable was sourced from 139 physical checks of near-surface permafrost presence/absence sampled across the variable boreal-wetland environment. Vegetation is the strongest predictor of near-surface permafrost in the regression. The regression predicts that 50.0% (minimum confidence: 36%) of the vegetated area is underlain by near-surface permafrost with a spatial accuracy of 72.8%. Analysis of data recorded across various burnt and not-burnt environments indicated that recent burn scenarios have significantly influenced the distribution of near-surface permafrost in the community. A spatial burn analysis predicted up to an 18.3% reduction in near-surface permafrost coverage, in a maximum burn scenario without factoring in the influence of climate change. The study highlights the potential that in an ecosystem with virtually homogeneous air temperature, ecosystem structure and disturbance history drive short-term changes in permafrost distribution and evolution. Thus, at the community level these factors should be considered as seriously as changes to air temperature as climate changes. Abstract Copyright (2022), John Wiley & Sons, Ltd.
DOI: 10.1002/ppp.2160
2022064293 Guo Lei (Chinese Academy of Sciences, Northwest Institute of Eco-Environment and Resources, Lanzhou, China); Wang Xinbin; Jiang Fuwei; Liu Youqian; Yu Qihao; You Yanhui and Wang Jinchang. Numerical experiments for improving the applications of two-phase closed thermosyphons in permafrost regions: Cold Regions Science and Technology, 204, Article 103680, 35 ref., December 2022. Based on Publisher-supplied data.
Two-phase closed thermosyphons (TPCTs) are widely used in enhancing mechanical strength of foundation soils in permafrost regions. However, engineering problems develop in embankments containing TPCTs. Based on numerical simulations, we herein discuss the influence of four important parameters, namely model size, daily variations in air and ground surface temperatures (AGST), decreasing cooling power of a TPCT, and adiabatic section, on the simulation accuracy or the application results of a TPCT. Results show that the simulated thermal influence of the TPCT can be severely impacted by the model size. It is also found that neglecting daily AGST variations results in 0.3-0.4°C temperature increase in soil 2 m away from the TPCT. The decreasing cooling power of a TPCT can increase the ground temperature. When the cooling power decreases by 30% and 50%, the ground temperature 2 m away from the TPCT increases by 0.2-0.3°C and 0.4-0.6°C in cold seasons, respectively. Although adiabatic section was applied in many TPCTs, but it has limited effect on the cooling performance of a TPCT. The results may help improving the accuracy of a simulation model and help optimize field applications of TPCTs in cold regions.
DOI: 10.1016/j.coldregions.2022.103680
2022064373 Li Xiaoying (Northeast Forestry University, Laboratory of Sustainable Forest Ecosystem Management, Harbin, China); Jin Huijun; Sun Long; Wang Hongwei; Huang Yadong; He Ruixia; Chang Xiaoli; Yu Shaopeng and Zang Shuying. TTOP-model-based maps of permafrost distribution in northeast China for 1961-2020: Permafrost and Periglacial Processes, 33(4), p. 425-435, illus. incl. 2 tables, sketch maps, 49 ref., December 2022.
Northeast China has experienced rapid and substantial climate warming over the past 60 years, and permafrost is degrading rapidly. In this study, permafrost distribution and extent in Northeast China were estimated from monitored ground surface temperatures using the temperature at the top of permafrost (TTOP) model and geographically weighted regression method. Using the TTOP model, the computed mean annual ground temperatures (MAGT@TOP) at the top of permafrost of Northeast China increased significantly from 1961-1990 (1.8°C) to 1991-2020 (3.0°C). The areal extents of permafrost defined by a subzero MAGT@TOP (MAGT@TOP ≤&eq;0°C) in Northeast China in the period 1961-1990 and 1991-2020 were estimated at 461.5´103 and 365.8´103 km2, respectively, indicating a decline of 95.7´103 km2. On average, the simulated MAGT@TOP values were 2.07°C lower than the observed MAGT@TOP values in boreholes. The linear correlation coefficient between the simulated and measured MAGT@TOP values was 0.63. Compared with the simulation results of other previous models, the result of this research is more reliable and accurate. The compiled maps of permafrost distribution can serve as an important reference for the study of permafrost changes in Northeast China. Abstract Copyright (2022), John Wiley & Sons, Ltd.
DOI: 10.1002/ppp.2157
2022064375 Monhonval, Arthur (Université Catholique de Louvain, Earth and Life Institute, Louvain-la-Neuve, Belgium); Strauss, Jens; Thomas, Maxime; Hirst, Catherine; Titeux, Hugues; Louis, Justin; Gilliot, Alexia; Bois d'Aische, Eléonore; Pereira, Benoît; Vandeuren, Aubry; Grosse, Guido; Schirrmeister, Lutz; Jongejans, Loeka L.; Ulrich, Mathias and Opfergelt, Sophie. Thermokarst processes increase the supply of stabilizing surfaces and elements (Fe, Mn, Al, and Ca) for mineral-organic carbon interactions: Permafrost and Periglacial Processes, 33(4), p. 452-469, illus. incl. 1 table, December 2022.
The stabilizing properties of mineral-organic carbon (OC) interactions have been studied in many soil environments (temperate soils, podzol lateritic soils, and paddy soils). Recently, interest in their role in permafrost regions is increasing as permafrost was identified as a hotspot of change. In thawing ice-rich permafrost regions, such as the Yedoma domain, 327-466 Gt of frozen OC is buried in deep sediments. Interactions between minerals and OC are important because OC is located very near the mineral matrix. Mineral surfaces and elements could mitigate recent and future greenhouse gas emissions through physical and/or physicochemical protection of OC. The dynamic changes in redox and pH conditions associated with thermokarst lake formation and drainage trigger metal-oxide dissolution and precipitation, likely influencing OC stabilization and microbial mineralization. However, the influence of thermokarst processes on mineral-OC interactions remains poorly constrained. In this study, we aim to characterize Fe, Mn, Al, and Ca minerals and their potential protective role for OC. Total and selective extractions were used to assess the crystalline and amorphous oxides or complexed metal pools as well as the organic acids found within these pools. We analyzed four sediment cores from an ice-rich permafrost area in Central Yakutia, which were drilled (i) in undisturbed Yedoma uplands, (ii) beneath a recent lake formed within Yedoma deposits, (iii) in a drained thermokarst lake basin, and (iv) beneath a mature thermokarst lake from the early Holocene period. We find a decrease in the amount of reactive Fe, Mn, Al, and Ca in the deposits on lake formation (promoting reduction reactions), and this was largely balanced by an increase in the amount of reactive metals in the deposits on lake drainage (promoting oxidation reactions). We demonstrate an increase in the metal to C molar ratio on thermokarst process, which may indicate an increase in metal-C bindings and could provide a higher protective role against microbial mineralization of organic matter. Finally, we find that an increase in mineral-OC interactions corresponded to a decrease in CO2 and CH4 gas emissions on thermokarst process. Mineral-OC interactions could mitigate greenhouse gas production from permafrost thaw as soon as lake drainage occurs. Abstract Copyright (2022), John Wiley & Sons, Ltd.
DOI: 10.1002/ppp.2162
2022064372 Wang, Qinxue (National Institute for Environmental Studies, Ibaraki, Japan); Okadera, Tomohiro; Watanabe, Masataka; Wu Tonghua and Ochirbat, Batkhishig. Ground warming and permafrost degradation in various terrestrial ecosystems in northcentral Mongolia: Permafrost and Periglacial Processes, 33(4), p. 406-424, illus. incl. strat. col., 3 tables, sketch map, 30 ref., December 2022.
To detect the response of permafrost to climate change in various terrestrial ecosystems, we established a permafrost monitoring network in 2007, which includes eight boreholes to monitor ground temperatures in forest, meadow, steppe, moderately dry steppe, and wetland ecosystems and three Automatic Weather Stations (AWS) to monitor climatic factors, such as wind speed (Ws), air temperature (Ta), relative humidity (RH), precipitation (P), solar radiation (Rs), net radiation (Rn), soil heat flux (SHF), soil temperature (Ts), and soil water content (SWC), in forest, meadow, and steppe ecosystems in north-central Mongolia. Major indicators, including mean annual ground temperature (MAGT), active layer thickness (ALT), and depth of zero annual amplitude (DZAA), were estimated to detect permafrost degradation. The results show that MAGT has increased by 0.00-0.02°C per year (almost no change) in the ice-poor permafrost areas and by 0.03-0.06°C per year in the ice-rich permafrost on pingos and wetlands. ALT showed an annual increase of -0.78 to 0.36 cm (almost no change) in the forest and meadow ecosystems and 2.3-7.2 cm in wetland ecosystems, whereas it increased by 23.0-28.9 cm per year in the steppe ecosystems over the last decade. This implies that the permafrost has degraded more rapidly in the steppe ecosystems than in other ecosystems. Based on correlation analysis, ALT is correlated to P in the meadow ecosystems and to SWC in the forest ecosystem, and MAGT is correlated to RH. However, both ALT and MAGT show a close correlation with major climatic factors, such as Ta, RH, SHF, and SWC in the steppe ecosystem. DZAA shows a close negative correlation with Ta in all ecosystems. These results provide evidence for permafrost degradation and its different responses to climate change in various terrestrial ecosystems. Abstract Copyright (2022), John Wiley & Sons, Ltd.
DOI: 10.1002/ppp.2161
2022064370 Wee, Julie (University of Fribourg, Department of Geosciences, Fribourg, Switzerland) and Delaloye, Reynald. Post-glacial dynamics of an alpine Little Ice Age glacitectonized frozen landform (Aget, western Swiss Alps): Permafrost and Periglacial Processes, 33(4), p. 370-385, illus. incl. 1 table, sketch map, 55 ref., December 2022.
Glaciers and frozen-debris landforms have coexisted and episodically or continuously interacted throughout the Holocene at elevations where the climate conditions are cold enough for permafrost to occur. In the European Alps, the Little Ice Age (LIA) characterized the apogee of the last interaction phase. In areas of consecutive post-LIA glacier shrinkage, the geomorphological dominant conditioning of the ongoing paraglacial phase may have transitioned from glacial to periglacial and later even shifted to post-periglacial. Such transitions can be observed through the morphodynamics of glacitectonized frozen landforms (GFLs), which are permafrost-related pre-existing frozen masses of debris deformed (tectonized) by the pressure exerted by an interacting glacier. This contribution aims at evidencing the processes driving the ongoing morphodynamical evolution of an actively back-creeping GFL within the LIA forefield of the Aget glacier on the basis of long-term time series of ground surface temperature, and in-situ geodetic and geoelectrical measurements. Our observations for the last two decades (1998-2020), which have been the warmest since the LIA, reveal a resistivity decrease in the permafrost body and a surface subsidence of up to a few centimeters per year. The former indicate a liquid water-to-ice content ratio increase within the permafrost body and the latter a ground ice melt at the permafrost table, both processes having taken place heterogeneously at the scale of the landform. The absence of acceleration of landform motion during that period despite a probable warming trend of the frozen ground may indicate that the ongoing degradation is reaching a tipping point at which processes related to interparticle friction and thinning of the permafrost body contribute to gradually inactivate the mechanism of permafrost creep. Abstract Copyright (2022), John Wiley & Sons, Ltd.
DOI: 10.1002/ppp.2158
2022064371 Yamkhin, Jambaljav (Mongolian Academy of Sciences, Institute of Geography and Geoecology, Ulaanbaatar, Mongolia); Yadamsuren, Gansukh; Khurelbaatar, Temuujin; Gansukh, Tsogt-Erdene; Tsogtbaatar, Undrakhtsetseg; Adiya, Saruulzaya; Yondon, Amarbayasgalan; Avirmed, Dashtseren and Natsagdorj, Sharkhuu. Spatial distribution mapping of permafrost in Mongolia using TTOP: Permafrost and Periglacial Processes, 33(4), p. 386-405, illus. incl. 7 tables, sketch maps, 74 ref., December 2022.
This study presents the results of permafrost mapping in Mongolia based on the TTOP (temperature-on-top-of-permafrost) approach, which were validated against in situ measurements at various locations. In situ measurements indicated that the mean annual ground temperature (MAGT) ranged from 0.6 to 2.2°C interannually, showing the greatest variability when furthest from 0°C. The differences between the modeled and measured MAGTs exceeded ±1°C in locations where permafrost was in a nonequilibrium state and was controlled predominantly by local factors. It was estimated that permafrost occupies one-third of Mongolia. We divided the extent of the permafrost into five zones: continuous, discontinuous, sporadic, isolated, and seasonally frozen ground. In total, the permafrost zones cover 3DF462.8´103 km2, accounting for 29.3% of Mongolia. Of this total area, continuous permafrost accounted for 118.3´103 km2 (7.5%), discontinuous permafrost 127.7´103 km2 (8.1%), sporadic permafrost 112.4´103 km2 (7.1%), and isolated permafrost 104.4´103 km2 (6.6%). Abstract Copyright (2022), John Wiley & Sons, Ltd.
DOI: 10.1002/ppp.2165
2022064292 Zhao, Yue (University of Alaska Anchorage, Department of Civil Engineering, Anchorage, AK) and Yang, Zhaohui Joey. Historical and long-term climate trends in warm permafrost regions; a case study of Bethel, AK: Cold Regions Science and Technology, 204, Article 103677, 57 ref., December 2022. Based on Publisher-supplied data.
Permafrost is very sensitive to climate factors, with warm permafrost particularly vulnerable to climate change. This paper aims to provide a detailed case study of climate trends of a high-latitude Alaskan site underlain by warm permafrost based on historical data and predictions from the Coupled Model Intercomparison Project Phase 5 (CMIP5). The climate data, including air temperature, precipitation, wind speed, and their annual and seasonal trends from 1950 to 2099, are presented for Bethel, Alaska. The downscaled data are compared with the historical data in the overlap period. Both air and design freezing and thawing indices are calculated using various methods. In comparison, the downscaled model predictions align well with air temperature and wind speed records but not for precipitation, indicating the need for further downscaling at a finer resolution. The historical annual temperature records show a warming rate of 0.40°C per decade, which is predicted to almost double to 0.78°C per decade in the 21st century, leading to shorter winters and longer summers. The historical annual precipitation increased by a rate of 14.8 mm per decade from 1950 to 2020, and this trend is predicted to continue but at a slightly lower rate. The wind speed decreased consistently from 1984 to 2020 by 0.9 km/h per decade. However, the CMIP5 predicts that such a trend will diminish, with the mean annual wind speed remaining almost unchanged in this century. The air freezing index exhibits a consistent downtrend from 1950 to 2020, whereas the air thawing index remained flat until 1980 and rose afterward; the CMIP5 predicts that both trends will continue in the 21st century. The design air freezing and thawing indices are sensitive to the assessment periods for both methods. An assessment period shorter than 30 years, e.g., ten years, is recommended to find design indices. It is conservative to use the monthly mean air temperature method for evaluating the design air freezing index and apply the extreme event method for the design thawing index.
DOI: 10.1016/j.coldregions.2022.103677
2022064379 Chen Cong (Lanzhou University, College of Earth and Environmental Sciences, Key Laboratory of Western China's Environmental Systems, Lanzhou, China); Peng Xiaoqing; Frauenfeld, Oliver W.; Zhao Yaohua; Yang Guangshang; Tian Weiwei; Li Xuanjia; Du Ran and Li Xiaodong. Comprehensive assessment of seasonally frozen ground changes in the Northern Hemisphere based on observations: Journal of Geophysical Research: Atmospheres, 127(20), Article e2022JD037306, illus. incl. 1 table, 42 ref., October 27, 2022.
Seasonally frozen ground (SFG) in the Northern Hemisphere (NH) plays a significant role in the earth system via changes in the freeze-thaw cycle. Previous studies primarily focus on permafrost; however, the SFG response to climate change on a hemispheric scale is uncertain due to a lack of observations. We rectify this with a newly assembled comprehensive database of 1,220 stations with daily observations. To quantify the spatiotemporal characteristics of SFG in response to climate change, we calculate eight variables with these observations: the first date of soil freeze (FFD), freezing duration (FDR), maximum freeze depth (MFD), the date of maximum freeze depth (MFDD), the last date of soil thaw (TLD), thawing duration (TDR), freeze-thaw duration (FTDR), and actual number of freezing days (AD). During the variables' common 1986-2005 period, MFD decreased 8.9 cm (9% change). FFD was later by 5.3 days (2% change), MFDD and TLD were earlier by 14.5 days (27% change) and 24.7 days (22% change), respectively, and FDR and TDR decreased by 9 days (11% change) and 4.6 days (10% change). FTDR and AD decreased 18.1 days (14% change) and 12.1 days (10% change), respectively. The spatial pattern of freeze-thaw variables depends on latitude and elevation, and varies by climatic zone: FTDR increases, going from the warm temperate climate, to the arid climate, and the snow and polar climates. The variability in freeze-thaw changes is mainly driven by air temperature and latitude, while precipitation, soil moisture, snow depth, and elevation are relatively insignificant at the hemispheric scale. Abstract Copyright (2022), American Geophysical Union. All Rights Reserved.
DOI: 10.1029/2022JD037306
2022064303 Winsemann, Jutta (Leibniz Universität Hannover, Institut für Geologie, Hanover, Germany); Hartmann, Tim; Lang, Jörg; Fälber, Runa and Lauer, Tobias. Depositional architecture and aggradation rates of sand-rich, supercritical alluvial fans; Control by autogenic processes or high-frequency climatic oscillations?: Sedimentary Geology, 440, Article 106238, illus. incl. 2 tables, geol. sketch maps, 224 ref., October 2022.
Alluvial fans are important paleoclimatic archives, that may record high-frequency climatic oscillations. However, climate signals may be overprinted or even be destroyed by autogenic processes caused by channel avulsion and lobe switching. Here we present new data from two different Late Pleistocene (MIS 3-2) alluvial fan systems in northern Germany and compare these systems to experimental alluvial fans and other field examples. The selected fan systems formed under similar climatic and tectonic conditions, but differ in size, type, and drainage area allowing to estimate the role of climate and autogenic controls on flow processes, facies architecture, and fan-stacking patterns. Luminescence dating is used to determine the timing of fan onset and aggradation. Fan onset occurred in response to climate change at the end of MIS 3 when temperatures decreased and periglacial climate conditions were established in northern central Europe. A related increase in sediment supply and strongly variable precipitation patterns probably promoted fan formation. The major period of fan aggradation was approximately between 33 and 18 ka, followed by fan inactivity, abandonment, and incision during the Lateglacial. The highest aggradation rates occurred during the early stage of fan building, when up to 35 m thick sediment accumulated within a few thousand years. Sand-rich, sheetflood-dominated fans are related to larger, low-gradient fan catchments. Steep depositional fan slopes (5-17°) and short-lived high-energy floods promoted supercritical flow conditions. Well sorted, sediment-laden, rapidly waning flows favored the deposition and preservation of supercritical bedforms and allowed for the aggradation of stable antidunes. Steep, dip-slope catchments enhanced stream gradients and promoted the transport of coarser sediments. These fans have lower gradient slopes (2-6°) and are dominated by channelized flows, alternating with periods of unconfined sheetfloods. Meter-scale coarsening upward successions, characterized by sandy sheetflood deposits at the base, overlain by multilateral or smaller single-story gravelly channel fills may be related to high-frequency climatic fluctuations or seasonal fluctuations in water and sediment supply. These coarsening-upward successions are commonly bounded by a paleo-active layer, from which ice-wedge casts penetrate downwards. The comparison to experimental fans and other field examples implies that the recurrent pattern of multistory, multilateral and single-story channel bodies with a lateral offset to vertical stacking pattern most probably was controlled by autogenic switch in an avulsion-dominated system. The change in deposition from alluvial-dominated processes to aeolian sedimentation with minor alluvial influences during the Lateglacial records alternation of dry and ephemeral wetter phases that are related to rapid climatic variations. The main phase of aeolian sand-sheet deposition probably correlates with Heinrich event H1 between approximately 18-16 ka and reflects sedimentation in response to aridification and high mean wind speeds.
DOI: 10.1016/j.sedgeo.2022.106238
2022057857 Zhao Xingmin (China Geological Survey, Department of Strategic Planning Research, Beijing, China); Deng Jian; Wen Zhigang; Rao Zhu; Yi Li; Liu Chen and Lu Cheng. Hydrocarbon gases in the shallow section of the Mohe permafrost, northeastern China; source for potential gas-hydrate formation: AAPG Bulletin, 106(10), p. 2013-2041, illus. incl. sects., 11 tables, geol. sketch map, 64 ref., October 2022.
Although conditions in the Mohe permafrost of northeastern China, including temperature, pressure, groundwater, gas migration, and host reservoirs, are favorable for gas-hydrate accumulation, no gas hydrates have been found because the gas availability remains problematic. Therefore, gas availability in this region has become a key research topic. In this study, the characteristics and distribution of hydrocarbon gases in the Mohe permafrost were analyzed to examine sources of potential gas-hydrate formation. For this purpose, 378 gas samples were analyzed for molecular and carbon and hydrogen isotope compositions. The results show that hydrocarbon gases mainly comprise methane (greater than 99%) at burial depths less than 1000 m. At depths greater than 1000 m, heavy hydrocarbons account for more than 2%, and the gas-dryness coefficient and C1/(C2+C3) ratios tend to decrease with increasing depths because of the chromatographic effect of upward gas migration or diffusion. The carbon isotope values of methane show an increasing trend with depth, whereas those of hydrogen isotopes show the opposite trend. The carbon and hydrogen isotopes of methane show a negative correlation, which is likely attributable to the mixing of 13C-depleted and D-enriched methane (produced mainly via carbon dioxide reduction at shallow depths) with 13C-enriched and D-depleted methane (formed via acetate fermentation at greater depths). From the gas and isotope compositions, microbial gas was inferred to dominate intervals at depths less than 1200 m. Mixed gases of microbial and thermogenic origins may occur at intermediate depth intervals between 1200 and 2300 m. Thermogenic gases are distributed at greater depths, with their formation facilitated by higher temperatures. Thus, gases for potential gas-hydrate formation may contain a combination of microbial and thermogenic gases migrated from deep intervals. Finally, potential concentrated hydrate deposits are believed to occur along gas-migration pathways, such as faults, in the Mohe Formation of the central-northern part of the Mohe Basin. In the future, fault zones, especially reverse faults and their adjacent fractures, and permeable sandstones in the Mohe Formation of the central-northern part of the basin should be the main target of gas-hydrate exploration.
DOI: 10.1306/06212217394
2022064276 Gubin, S. V. (Russian Academy of Sciences, Institute of Physicochemical and Biological Problems of Soil Science, Pushchino, Russian Federation); Lupachev, A. V. and Khodzhaeva, A. K. Soils of accumulative coasts of the East Siberian Sea: Eurasian Soil Science, 55(9), p. 1173-1184, illus. incl. 3 tables, sketch map, 31 ref., September 2022.
Thalassosols developing on the accumulative coasts of the East Siberian Sea include initial soils of regularly flooded tidal flats with sparse vegetation, episodically flooded marsh soils with different degrees of salinization, and maritime soils that are morphologically close to the zonal soils but are affected by salts transferred by wind with seawater drops and organomineral matter from the non-vegetated seashores. Weakly developed marsh soils have the initial features and structure of the marine sediments combined with the processes of salinization; sulfate reduction; gleyzation; cryogenic mass exchange; as well as the transfer, accumulation, and weak biochemical transformation of the raw organic matter. Soils with different degrees of salinization are formed on tidal marshes and are characterized by some redistribution of salts in the soil profile with weak accumulation of salts in the uppermost organic horizons and in the suprapermafrost layers along with pronounced sulfate reduction. Slightly saline organogenic and peaty gleyic soils predominate in the areas of sedge marshes. The majority of studied marsh soils form under the conditions of distinct cryogenic polygonal microtopography, waterlogging, and relatively shallow permafrost.
DOI: 10.1134/S106422932209006X
2022058735 Hu Guojie (Chinese Academy of Sciences, Northwest Institute of Eco-Environment and Resources, Lanzhou, China); Zhao Lin; Wu Tonghua; Wu Xiaodong; Park, Hotaek; Li Ren; Zhu Xiaofan; Ni Jie; Zou Defu; Hao Junming and Li Wangping. Continued warming of the permafrost regions over the Northern Hemisphere under future climate change: Earth's Future, 10(9), Article e2022EF002835, illus. incl. 7 tables, 122 ref., September 2022.
Surface air temperatures can directly affect the thermal state of permafrost in the permafrost region of the Northern Hemisphere (PRONH). It is necessary to understand the trends in air temperatures and consider actual CMIP future scenario output instead of a linear temperature increase over different permafrost regions. In this study, air temperatures from 23 models of the sixth coupled-model intercomparison project (CMIP6) are evaluated against observational data from the PRONH. It is shown that most of the models reasonably represent the dominant characteristics of air temperature variations. Under three different future scenarios, air temperature and warming trends are examined using an optimal model ensemble. Results show that mean annual air temperature (MAAT) is higher in sporadic-permafrost and isolated-permafrost regions than in continuous-permafrost regions. MAAT warming rates were 0.10°C/decade and 0.35°C/decade from 1900 to 2014 and from 1980 to 2014, respectively, and were 0.09°C/decade, 0.38°C/decade, and 0.95°C/decade from 2015 to 2100 under the low- to high-emission scenarios. Air temperature varies considerably between the high-altitude, transitional, and high-latitude permafrost regions (HLR), and warming trends are the greatest in HLR under future scenarios. Moreover, warming trends in different permafrost classes vary little from the historical values from 1900 to 2014, and with a gradual increase from isolated-permafrost regions to continuous-permafrost regions under future scenarios. The results suggested that air temperatures in the PRONH warmed approximately 1.6 times faster than global air temperatures from 1980 to 2014 and under the three future scenarios. Abstract Copyright (2022), The Authors. Earth's Future published by Wiley Periodicals LLC on behalf of American Geophysical Union.
DOI: 10.1029/2022EF002835
2022064277 Shamrikova, E. V. (Russian Academy of Sciences, Institute of Biology, Komi Science Center, Syktyvkar, Russian Federation); Kubik, O. S. and Deneva, S. V. Fractional composition of the compounds of some typomorphic chemical elements in soils of the Barents Sea (Khaipudyr Bay) coastal area: Eurasian Soil Science, 55(9), p. 1235-1247, illus. incl. 3 tables, 72 ref., September 2022.
Information on different compounds of elements, such as Na, K, Ca, Mg, Al, Fe, and Mn, contributes to our understanding of the genesis of poorly studied soils of northern coasts. The analysis has been carried out of the composition of various forms of compounds. To determine total element contents, a mixture of concentrated HF, HClO4, and HCl was used; acid-soluble forms were extracted with a mixture of concentrated HNO3 and H2O2; and acetate ammonium buffer solution was used to determine mobile forms. It is shown that the amount elements added to the tidal marsh zone is largely determined by the volume and composition of solids entering with seawater and with runoff from coastal catchments. For mineral soil horizons, a close correlation is found between the contents of clay fraction and exchangeable forms of K, Mg, and Al (R2 = 0.4-0.5), as well as between the contents of clay and highly mobile forms of these elements and Fe (R2 = 0.6-0.8). The distribution of elements along the profile of zonal soils on the highest positions of the relief is significantly influenced by the permafrost conditions and the aerial transfer of salts with seawater drops.
DOI: 10.1134/S1064229322090149
2022058734 Shirley, Ian A. (Lawrence Berkeley National Laboratory, Earth and Environmental Sciences Area, Berkeley, CA); Mekonnen, Zelalem A.; Wainwright, Haruko; Romanovsky, Vladimir E.; Grant, Robert F.; Hubbard, Susan S.; Riley, William J. and Dafflon, Baptiste. Near-surface hydrology and soil properties drive heterogeneity in permafrost distribution, vegetation dynamics, and carbon cycling in a sub-arctic watershed: Journal of Geophysical Research: Biogeosciences, 127(9), Article e2022JG006864, illus. incl. 1 table, 71 ref., September 2022.
Discontinuous permafrost environments exhibit strong spatial heterogeneity at scales too small to be driven by weather forcing or captured by Earth System Models. Here we analyze effects of observed spatial heterogeneity in soil and vegetation properties, hydrology, and thermal dynamics on ecosystem carbon dynamics in a watershed on the Seward Peninsula in Alaska. We apply a Morris global sensitivity analysis to a process-rich, successfully tested terrestrial ecosystem model (TEM), ecosys, varying soil properties, boundary conditions, and weather forcing. We show that landscape heterogeneity strongly impacts soil temperatures and vegetation composition. Snow depth, O-horizon thickness, and near-surface water content, which vary at scales of O(m), control the soil thermal regime more than an air temperature gradient corresponding to a 140 km north-south distance. High shrub productivity is simulated only in talik (perennially unfrozen) soils with high nitrogen availability. Through these effects on plant and permafrost dynamics, landscape heterogeneity impacts ecosystem productivity. Simulations with near-surface taliks have higher microbial respiration (by 78.0 gC m-2 yr-1) and higher net primary productivity (by 104.9 gC m-2 yr-1) compared to runs with near-surface permafrost, and simulations with high shrub productivity have outlying values of net carbon uptake. We explored the prediction uncertainty associated with ignoring observed landscape heterogeneity, and found that watershed net carbon uptake is 60% larger when heterogeneity is accounted for. Our results highlight the complexity inherent in discontinuous permafrost environments and demonstrate that missing representation of subgrid heterogeneity in TEMs could bias predictions of high-latitude carbon budget. Abstract Copyright (2022), The Authors.
DOI: 10.1029/2022JG006864
2022064028 Vasile, Mirela (University of Bucharest, GEODAR Research Group for Geomorphology, Bucharest, Romania); Vespremeanu-Stroe, Alfred; Pascal, Daniela; Braucher, Regis; Plesoianu, Alin; Popescu, Razvan and Etzelmuller, Bernd. Rock walls distribution and Holocene evolution in a mid-latitude mountain range (the Romanian Carpathians): Geomorphology, 413, Article 108351, illus. incl. 5 tables, geol. sketch maps, 95 ref., September 15, 2022.
Rock walls in high mountain areas are the expression of long-term slopes response (103-105 years) to tectonics, weathering and denudation and a major source of sediment and hazard. Controls of mountain rock walls (RW) distribution and the response to post-glacial evolution are rarely discussed in the literature at the scale of mountain ranges. Using a database of 791 RW mapped in the Romanian Carpathians, we present their distribution and morphometry in respect to lithological classes, structural features and topography and relate their exposure to post-Younger Dryas (Holocene) rock slope failure chronology. Statistical analysis results show the high significance of structural and tectonic control on RW distribution, which prevails in sedimentary units where it imposed the predominance of West and North orientations and led to the formation of RW with dimensions up to a degree higher compared to other lithologies. Morphometric data indicate that metamorphic and igneous RW (linked to a great extent to glacial valleys and cirques headwalls) are usually restricted to the highest sectors of the mountain slopes, being characterized by reduced relative heights, asymmetrically distributed, common on the North-exposed slopes and extremely rare on the South. Based on 38 in-situ produced 10Be surface exposure ages obtained on meter-sized boulders from the Southern and Eastern Carpathians, we hypothesise that metamorphic and igneous RW in the formerly glaciated Carpathian valleys were significantly shaped during Early Holocene (before 9 ka) by rock slope failures events that followed the deglaciation of the highest cirques and by intense RW permafrost degradation, which also affected some of the highest sedimentary units. We associate the long-term imprints of frost weathering to the significant North/South RW and rock glaciers distribution asymmetry, also identified in other mid-latitude mountain sites with similar topographic constraints.
DOI: 10.1016/j.geomorph.2022.108351
2022058729 Zolkos, Scott (University of Alberta, Department of Biological Sciences, Edmonton, AB, Canada); Tank, Suzanne E.; Kokelj, Steven V.; Striegl, Robert G.; Shakil, Sarah; Voigt, Carolina; Sonnentag, Oliver; Quinton, William L.; Schuur, Edward A. G.; Zona, Donatella; Lafleur, Peter M.; Sullivan, Ryan C.; Ueyama, Masahito; Billesbach, David; Cook, David; Humphreys, Elyn R. and Marsh, Philip. Permafrost landscape history shapes fluvial chemistry, ecosystem carbon balance, and potential trajectories of future change: Global Biogeochemical Cycles, 36(9), Article e2022GB007403, illus. incl. 3 tables, sketch map, 107 ref., September 2022.
Intensifying permafrost thaw alters carbon cycling by mobilizing large amounts of terrestrial substrate into aquatic ecosystems. Yet, few studies have measured aquatic carbon fluxes and constrained drivers of ecosystem carbon balance across heterogeneous Arctic landscapes. Here, we characterized hydrochemical and landscape controls on fluvial carbon cycling, quantified fluvial carbon fluxes, and estimated fluvial contributions to ecosystem carbon balance across 33 watersheds in four ecoregions in the continuous permafrost zone of the western Canadian Arctic: unglaciated uplands, ice-rich moraine, and organic-rich lowlands and till plains. Major ions, stable isotopes, and carbon speciation and fluxes revealed patterns in carbon cycling across ecoregions defined by terrain relief and accumulation of organics. In previously unglaciated mountainous watersheds, bicarbonate dominated carbon export (70% of total) due to chemical weathering of bedrock. In lowland watersheds, where soil organic carbon stores were largest, lateral transport of dissolved organic carbon (50%) and efflux of biotic CO2 (25%) dominated. In watersheds affected by thaw-induced mass wasting, erosion of ice-rich tills enhanced chemical weathering and increased particulate carbon fluxes by two orders of magnitude. From an ecosystem carbon balance perspective, fluvial carbon export in watersheds not affected by thaw-induced wasting was, on average, equivalent to 6%-16% of estimated net ecosystem exchange (NEE). In watersheds affected by thaw-induced wasting, fluvial carbon export approached 60% of NEE. Because future intensification of thermokarst activity will amplify fluvial carbon export, determining the fate of carbon across diverse northern landscapes is a priority for constraining trajectories of permafrost region ecosystem carbon balance. Abstract Copyright (2022), The Authors.
DOI: 10.1029/2022GB007403
2022062848 Chen Jie (Chinese Academy of Sciences, Northwest Institute of Eco-Environment and Resources, State Key Laboratory of Cryospheric Science, Lanzhou, China); Wu Tonghua; Liu Lin; Gong Wenyu; Zwieback, Simon; Zou Defu; Zhu Xiaofan; Hu Guojie; Du Erji; Wu Xiaodong; Li Ren and Yang Sizhong. Increased water content in the active layer revealed by regional-scale InSAR and independent component analysis on the central Qinghai-Tibet Plateau: Geophysical Research Letters, 49(15), Paper no. e2021GL097586, illus. incl. sketch maps, 51 ref., August 16, 2022.
Isolating seasonal deformation from Interferometric Synthetic Aperture Radar (InSAR) time-series is critical to quantitative understanding the freeze-thaw processes in permafrost regions. Physics- or statistics-based approaches have been developed to extract seasonal deformation, yet both constraining their evolution in time domain, and thus impeded the quantification of their amplitude variability especially over large scales. By applying Independent Component Analysis (ICA) on Sentinel-1 InSAR measurements during 2015-2019 on the central Qinghai-Tibet Plateau, we reveal that the averaged seasonal deformation is increasing with a linear trend of around 0.17 cm/year. The growing seasonal amplitude is attributed to an 8 cm increase of the Equivalent Water Thickness in the active layer. The results demonstrate the capability of ICA-based decomposition on isolating freeze-thaw-related deformation from other components. The large-scale spatial distribution of varied seasonal deformation can provide new insight into quantifying the water mass balance in vast permafrost regions. Abstract Copyright (2022). American Geophysical Union. All Rights Reserved.
DOI: 10.1029/2021GL097586
2022058522 Shelef, Eitan (University of Pittsburgh, Department of Geology and Environmental Science, Pittsburgh, PA); Griffore, Melissa; Mark, Sam; Coleman, Tim; Wondolowski, Nick; Lasher, G. Everett and Abbott, Mark. Sensitivity of erosion-rate in permafrost landscapes to changing climatic and environmental conditions based on lake sediments from northwestern Alaska: Earth's Future, 10(8), Article e2022EF002779, illus., 43 ref., August 2022.
Erosion of landscapes underlaid by permafrost can transform sediment and nutrient fluxes, surface and subsurface hydrology, soil properties, and rates of permafrost thaw, thus changing ecosystems and carbon emissions in high latitude regions with potential implications for global climate. However, future rates of erosion and sediment transport are difficult to predict as they depend on complex interactions between climatic and environmental parameters such as temperature, precipitation, permafrost, vegetation, wildfires, and hydrology. Thus, despite the potential influence of erosion on the future of the Arctic and global systems, the relations between erosion-rate and these parameters, as well as their relative importance, remain largely unquantified. Here we quantify these relations based on a sedimentary record from Burial Lake, Alaska, one of the richest datasets of Arctic lake deposits. We apply a set of bi- and multi-variate techniques to explore the association between the flux of terrigenous sediments into the lake (a proxy for erosion-rate) and a variety of biogeochemical sedimentary proxies for paleoclimatic and environmental conditions over the past 25 cal ka BP. Our results show that erosion-rate is most strongly associated with temperature and vegetation proxies, and that erosion-rate decreases with increased temperature, pollen-counts, and abundance of pollen from shrubs and trees. Other proxies, such as those associated with fire frequency, aeolian dust supply, mass wasting and hydrologic conditions, play a secondary role. The marginal effects of the sedimentary-proxies on erosion-rate are often threshold dependent, highlighting the potential for strong non-linear changes in erosion in response to future changes in Arctic conditions. Abstract Copyright (2022), The Authors. Earth's Future published by Wiley Periodicals LLC on behalf of American Geophysical Union.
DOI: 10.1029/2022EF002779
2022058508 Xu Lihua (China University of Geosciences, School of Water Resources and Environment, Beijing, China) and Gao Bing. Understanding the effects of cold and warm season air warming on the permafrost hydrology changes in the source region of the Lancang River, the Qinghai-Tibetan Plateau: Journal of Geophysical Research: Atmospheres, 127(16), Article e2022JD036551, illus. incl. 2 tables, sketch maps, 64 ref., August 27, 2022.
Cold season air warming was more rapid than warm season air warming on the Qinghai-Tibetan Plateau (QTP). However, the effect of this asymmetrical seasonal air warming on permafrost hydrological changes has not been fully understood. This study applied a distributed cryospheric hydrological model to evaluate the effects of different seasonal air warming on the changes in frozen soil and hydrological processes in a typical catchment, the source region of the Lancang River on the eastern QTP. The results show that the area of permafrost reduced by 14.0%. The maximum frozen depth of seasonally frozen ground (MFDSFG) decreased at 5.0 cm decade-1, and the active layer thickness (ALT) of permafrost increased by 3.3 cm decade-1. Controlled experiments illustrate that cold season air warming dominated the reduction in MFDSFG which caused the liquid soil moisture increase in seasonally frozen ground, and warm season air warming primarily determined the increase in ALT which enhanced the liquid soil moisture in permafrost. Cold season air warming had a greater effect on runoff than warm season air warming because it dominated the permafrost degradation into seasonally frozen ground. In the region where permafrost degraded into seasonally frozen ground, both the cold and warm season air warming contributed to the soil liquid water increase, and the cold season warming had a greater effect due to its more important role in thermal degradation of permafrost. The findings of this study reveal different complex impacts of cold and warm season air warming on permafrost hydrological changes on the QTP. Abstract Copyright (2022), American Geophysical Union. All Rights Reserved.
DOI: 10.1029/2022JD036551
2022057120 Domine, Florent (Université Laval, Takuvik Joint International Laboratory, Quebec City, QC, Canada); Fourteau, Kévin; Picard, Ghislain; Lackner, Georg; Sarrazin, Denis and Poirier, Mathilde. Permafrost cooled in winter by thermal bridging through snow-covered shrub branches: Nature Geoscience, 15(7), p. 554-560, illus. incl. 1 table, sketch maps, 51 ref., July 2022.
DOI: 10.1038/s41561-022-00979-2
2022057113 Farquharson, Louise Melanie (University of Alaska, Fairbanks, Geophysical Institute, Permafrost Laboratory, Fairbanks, AK); Romanovsky, Vladimir E.; Kholodov, Alexander and Nicolsky, Dmitry. Sub-aerial talik formation observed across the discontinuous permafrost zone of Alaska: Nature Geoscience, 15(6), p. 475-481, illus. incl. geol. sketch map, 59 ref., June 2022.
DOI: 10.1038/s41561-022-00952-z
2022061596 Opekunov, Anatoly (Saint Petersburg State University, Institute of Earth Sciences, Saint Petersburg, Russian Federation); Opekunova, Marina; Kukushkin, Stepan and Lisenkov, Sergey. Impact of drilling waste pollution on land cover in a high subarctic forest-tundra zone: Pedosphere, 32(3), p. 414-425, illus. incl. 4 tables, sketch map, 32 ref., June 2022.
Global climate changes can lead to the destruction of the permafrost zone and contribute to the active transfer of pollutants to natural waters. This can be especially pronounced in the areas of oil and gas production in the Arctic. This study aimed to define the landscape components (i.e., groundwater, soil water, soil, and indicator plant species) of chemical pollution with metals, oil hydrocarbons, and polycyclic aromatic hydrocarbons, from the discharge of drill cuttings. Studies at two sites in the forest-tundra zone of Western Siberia (Russia) were carried out within two years of pollution. Pollutant migration was found in peaty-gley heavy loamy soils andiron-illuvial clayey podburs, but lateral migration of different pollutants did not exceed 200 m. Additionally, radial migration was practically absent owing to the high buffering capacity of the soil organic horizon and the upward flow of matter in the seasonal melt layer. The main indicators of drilling waste pollution were high concentrations of Sr, Ba, petroleum hydrocarbons, and Cl- ions. At the waste disposal sites, the concentration of Ba and Sr in the soil water were 1 150 and 1 410 mgL-1, respectively; in groundwater, they reached 721 and 2 360 mgL-1, respectively. In the soil, Ba and Sr accumulated in the peatyhorizon (798 and 706 mg kg-1, respectively). The concentration of Cl- ions in the soil water at the site of waste discharge was 1 912 mgL-1, and at a distance of 200 m, it decreased to 77.4 mg L-1. The Cl- concentration in the groundwater was lower, and at a distance of 200 m, it was 38.9 mg L-1. The highest concentration of petroleum hydrocarbons in the surface layer was found in the peaty-gley soils (up to 2 400 mg kg-1). In glandular-illuvial podburs, it was 420 mg kg-1. In horizons BH and BC, it was close to the background values (27 and 33 mg kg-1, respectively). Alkalinization of soils and water under the influence of drill cuttings led to the death of oligotrophic and acidophilic vegetation at a distance of up to 50 m, and to the restructuring of the species and spatial structure of plant communities up to 100 m.
DOI: 10.1016/S1002-0160(21)60083-8
2022063948 Yoshikawa, Kenji (University of Alaska, Water and Environmental Research Center, Fairbanks, AK); Maslakov, Alexey A.; Kraev, Gleb; Ikuta, Hiroko; Romanovsky, Vladimir E.; George, J. Craig; Klene, Anna E. and Nyland, Kelsey E. Food storage in permafrost and seasonally frozen ground in Chukotka and Alaska communities: Arctic, 75(2), p. 225-241 (French, Russian sum.), illus. incl. 1 table, sketch map, 34 ref., June 2022.
DOI: 10.14430/arctic75259
2022056693 Kang, Myunghak (University of Ottawa, Department of Earth and Environmental Sciences, Ottawa, ON, Canada); Skierszkan, Elliott; Brennan, Sean; Fernandez, Diego P.; Yang, Zhaoping; Girard, Isabelle; Gammon, Paul; de Laplante, Ghislain and Bataille, Clément P. Controls of lithium isotope spatial variability across the Yukon River; implications for weathering processes in a warming subarctic basin: Geochimica et Cosmochimica Acta, 323, p. 1-19, illus. incl. 1 table, sketch maps, 101 ref., April 15, 2022.
With ongoing global warming and permafrost thawing, weathering processes will change on the Yukon River, with risks for water quality and ecosystem sustainability. Here, we explore the relationship between weathering processes and permafrost cover using elemental concentration and strontium and lithium isotopic data in the dissolved load of 102 samples collected during the summer across most major tributaries of the Yukon River. The Yukon River basin is dominated by silicate weathering with a high contribution from young volcanic rock units. In glaciated mountainous zones, we observe higher carbonate weathering contribution, low Li/Na ratios and low d7Li values (<15 ppm). In these areas, the high denudation rate and high supply of fresh minerals associated with alpine glaciers favor congruent silicate weathering, and sulfide oxidation accelerates carbonate weathering. In floodplains covered by continuous permafrost, we observe a high carbonate weathering contribution, relatively high Li/Na ratios, and low d7Li values (~18 ppm). We argue that the minimal water-rock interactions in this setting inhibit silicate weathering and favor congruent weathering of easily weatherable minerals (i.e., carbonates). Conversely, in areas with discontinuous or sporadic permafrost, we observe a dominance of silicate weathering, with higher and more variable Li/Na ratios and high d7Li values (11-33 ppm). In this setting, longer water-rock interactions combined with the high supply of fresh minerals from mountain zones favor more incongruent weathering. The unique history of Pleistocene glaciations on the Yukon River basin also influences weathering processes. Many areas of the basin were never glaciated during the Pleistocene, and rivers draining those regions have higher d7Li values suggesting more incongruent weathering associated with deeper flow paths and longer water residence time in the regolith. Our work underlines that water-rock interactions, including active layer weathering and groundwater inputs, are highly dependent on climate conditions and glacial processes across the Yukon River basin, with key implications for future water quality in this warming basin.
DOI: 10.1016/j.gca.2022.02.016
2022063950 Lara, Mark J. (University of Illinois at Urbana-Champaign, Champaign, IL). Thawing permafrost is roiling the Arctic landscape, driven by a hidden world of changes beneath the surface as the climate warms: The Conversation, April 12, 2022, illus., April 12, 2022.
URL: https://theconversation.com/thawing-permafrost-is-roiling-the-arctic-landscape-d ...
2022056689 Lozhkin, Anatoly (Russian Academy of Sciences, Far East Branch, North East Interdisciplinary Science Research Institute N. A. Shilo, Magadan, Russian Federation) and Anderson, Patricia. The influence of permafrost processes and paludification on landscapes in mountain settings of the upper Kolyma Basin (western Beringia): Quaternary International, 616, p. 87-98, illus. incl. charts, 3 tables, sketch maps, 62 ref., April 10, 2022.
Lithological and paleovegetation data from sites in the Elikchan region of the Upper Kolyma basin provide insights into the permafrost history of the mountain valleys of interior Western Beringia. The Elikchan records show a period of peat accumulation between ~12,000 and 9500 cal BP, which parallels trends in the northern coastal lowlands. This interval corresponds to a time when summers were warmer and drier than present and the previously established Betula-Alnus shrub tundra was replaced by Larix-Betula-Populus forest in both the interior valleys and northern lowlands. The Elikchan sites indicate that thermokarst processes continued throughout the Middle and Late Holocene, with the development of small ponds in the middle of ice-wedge polygons, their subsequent expansion to form thermokarst lakes, the periodic drainage or migration of these lakes, and the intermittent formation of stable surfaces as indicated by soil development. The arrival of Pinus pumila in the region ~10,000 cal BP suggests an increase in snow cover, a change that would enhance ground insulation, deepen the active layer, and increase permafrost thaw. Although such conditions might favor another interval of peat growth, peat accumulation apparently occurred only during the Early Holocene in the Elikchan region. Modern permafrost-vegetation-climate studies and sensitivity experiments using a Beringian paleoclimate model underscore the importance of seasonality when trying to unravel the complex climate and vegetation feedbacks that have influenced and will continue to affect permafrost landscapes.
DOI: 10.1016/j.quaint.2021.12.011
2022056688 Margielewski, Wlodzimierz (Polish Academy of Sciences, Institute of Nature Conservation, Krakow, Poland); Obidowicz, Andrzej; Zernitskaya, Valentina and Korzen, Katarzyna. Late glacial and Holocene palaeoenvironmental changes recorded in landslide fens deposits in the Polish Outer Western Carpathians (southern Poland): Quaternary International, 616, p. 67-86, illus. incl. strat. col., charts, sects., 2 tables, geol. sketch maps, 83 ref., April 10, 2022.
In the northern part of the Polish Outer Western Carpathians, the Beskid Makowski Mts., four landslides formed during the Late Glacial have been identified, so far. Within the depositional sequences (organic-mineral) of fens occurring in landslide depressions, palaeoenvironmental changes of the Late Glacial and the Holocene are recorded. The oldest of fen, started to form in the Oldest Dryas Stadial, the younger ones - in the Bolling Interstadial (two fens) and in the Older Dryas Stadial. The thickness of fen deposits varies from 1.5 m to 4.5 m. The sediments deposited in the Late Glacial represent long sequences (reaching 50-80% of the profile), whereas the Holocene deposits are reduced here due to the occurrence of long-lasting sedimentation gaps (hiatuses). The reconstruction of palaeoenvironment was carried out on the basis of pollen and lithological (loss on ignition, areometric) analyses along with more than 45 14C datings. In the Late Glacial sequences of the examined logs, mineral horizons interlaying organic deposits were affected by periodic climate warmings resulting in the permafrost melting during the Bolling and the Allerod Interstadials. In the Late Glacial deposits there are sequences (ca 0.5 m thick) deposited during the Older Dryas Stadial. The Allerod in the analyzed logs is bipartite: the lower sections (AL-1) are usually represented by peat deposition, whereas in the upper parts of the logs (AL-2) numerous minerogenic (clay, silty clay) inserts confirm the climate humidity growth (or permafrost melting) during the Gerzensee Oscillation. In the Late Glacial deposits, pollen of thermophilous trees, such as Corylus, Tilia, Quercus, Carpinus, as well as (typical for the Subboreal Phase) Abies alba and Fagus sylvatica occur, which may indicate the presence of thermophilous refugia in this part of the Carpathians. During the middle part of the Younger Dryas Stadial climate cooling, the widespread gradual increase in the delivery of allochthonous material to fens is related to permafrost melting. This process is finished by the deposition of clay and silty clay horizon at the beginning of the Holocene (Preboreal). The lack of the depositional sequences of the Boreal, Atlantic and partly the Subboreal phases in the majority of the logs is caused by the erosional removal of sediments during the climate humidity growth at the beginning of the Subboreal and the Subatlantic phases.
DOI: 10.1016/j.quaint.2021.11.001
2022056684 Pawlowska, Kamilla (Adam Mickiewicz University, Institute of Geology, Poznah, Poland); Zielinski, Tomasz; Woronko, Barbara; Sobkowiak-Tabaka, Iwona and Stachowicz-Rybka, Renata. Integrated environmental records in late Pleistocene Poland; the paleofluvial regime and paleoclimate inferred from Krosinko site: Quaternary International, 616, p. 12-29, illus. incl. sects., 2 plates, 3 tables, geol. sketch maps, 83 ref., April 10, 2022.
Multiproxy analyses performed at the Krosinko site in the Warsaw-Berlin ice marginal valley have provided data that characterize the depositional conditions, the paleofluvial regime, and the paleoclimate and help reconstruct the paleo-environment at a time of significant sediment (alluvium) accumulation (starting in central Poland ca. 45 ka BP). The sedimentological study, including sand-grain morphology and micromorphology analyses, reveals the presence at Krosinko of a meandering river and of a braided river during the Eemian (MIS 5e) and Upper Pleniweichselian (MIS 2), respectively. The fluvial regime changed over time, from low-energy, through high-energy, to low-energy, as documented by the differently formed sedimentary units A-D (vertical sedimentary succession from base to top: sandy silt, sand, gravelly sand, and sand). Sedimentary unit A and the lower part of unit B were accumulated in the Eemian interglacial (MIS 5e) by the low-energy meandering river. The high-energy fluvial environment during the Weichselian is associated with long, intense sediment transport, organic remains, and flints, as confirmed by taphonomic studies on conifer cones (Picea cf. abies) and wood remains (Juniperus). The river operated under distinct environmental conditions. First, during the accumulation of the upper part of unit B and unit C, there was a strong influence of freezing and aeolian weathering, which weakened significantly over time (unit D). This in turn indicates a change in climate from periglacial (upper part of unit B and unit C), when we also document the presence of permafrost in the subsurface or relatively deep seasonal frost, to temperate (unit D). With warming in the Holocene (MIS 1), an oxbow lake developed in Krosinko, the presence of which is recorded by peat.
DOI: 10.1016/j.quaint.2022.01.009
2022063993 Li Shuangyang (Chinese Academy of Sciences, Northwest Institute of Eco-Environment and Resources, State Key Laboratory of Frozen Soil Engineering, Lanzhou, China); Li Gen; Wang Chong; Lai Yuanming; Yang Jiale and Zhang Jing. Optimal reinforcement for improving the thermal performance of a permafrost tunnel based on coupled heat-mass transfer: Tunnelling and Underground Space Technology, 121, Article 104331, illus. incl. 1 table, 20 ref., March 2022.
Over 80% of cold-region tunnels (CRTs) suffer from heavy periodic freeze-thaw actions, and therefore, their normal safe operations cannot be guaranteed. To mitigate freeze-thaw damage to CRTs, thermal insulation layers (TILs) were used to prevent external heat from penetrating the surrounding rock of CRTs. TILs were often laid between two linings of CRTs with a uniform thickness along the whole tunnel based on a single thermal conduction calculation or engineering analogy method, which was not only uneconomical but also unsafe. Thus, freeze-thaw damage still occurred at the entrance of the CRTs. To solve this engineering problem, we took the Fenghuoshan Tunnel in permafrost regions as an example and proposed a coupled heat-mass transfer model based on mass, energy and momentum conservation principles. The numerical model was indicated to be accurate by comparing the computed and monitored temperatures. The subsequent numerical results show that the heat and mass exchanges between the air inside the tunnel and tunnel wall make the air velocities vary with seasonal alternation, and therefore, temperatures of the surrounding permafrost exhibit evident differences on the temporal and spatial scales, according to which the most unfavorable position and time point are selected to design an optimal reinforcement for improving the thermal performance. Based on a series of heat-mass transfer simulations with different thicknesses of aerogel felt, an optimal changeable thickness of aerogel felt along the whole tunnel is obtained to improve the thermal performance of the Fenghuoshan Tunnel. If the permafrost tunnel is reinforced by this approach, the highest temperatures of the surrounding permafrost near the tunnel are less than approximately -0.44°C, implying that the optimal reinforcement is effective and can control the freeze-thaw damage of the Fenghuoshan Tunnel. This study provides theoretical support for designing a safe and economical reinforcement on permafrost tunnels and understanding the coupled heat-mass transfer processes in tunnels.
DOI: 10.1016/j.tust.2021.104331
2022063787 Wang Luyang (Chinese Academy of Sciences, Northwest Institute of Eco-Environment and Resources, Lanzhou, China); Wu Qingbai; Fu Ziteng; Jiang Guanli; Liu Yali and Xu Kunming. Aeolian sand accumulation and land desertification over the past 1,500 years as revealed by two aeolian dunes in the Beiluhe Basin on interior Qinghai-Tibet Plateau, SW China: Quaternary International, 613, p. 101-117, illus. incl. sketch maps, 6 tables, sects., 112 ref., March 10, 2022.
As an important region of desertification in China, the Qinghai-Tibetan Plateau (QTP) has attracted great attention. However, the study of land desertification history at the millennia-scale on the interior plateau is grossly inadequate. In a severely and rapidly desertifying area in the Beiluhe Basin on the interior QTP, grain-size distributions, sand particle morphologies, and 7 available optically stimulated luminescence (OSL) ages of sand sediment from two fixed aeolian dunes were obtained by several laboratory tests. Combining these results with plateau paleoclimate and contemporary aeolian sand activities in several adjacent regions, two phases of evident enhanced aeolian sand accumulation corresponding to desert expansion over the past 1500 years in the study region were identified. The first enhanced phase (850-700 a B.P.) might have been closely related to suitable trapping of denser vegetation cover and degradation of permafrost on the QTP as a consequence of warm and wet climates. Reactivation of local older sediments caused by cold and dry climates might have been responsible for the second enhanced phase (1400-1200 a B.P.). Permafrost plays an important role in aeolian sand accumulation and desertification on the QTP. However, expansion (or degradation) of permafrost has not always prevented (or promoted) aeolian desertification development on the QTP since the Last Glaciation Maximum (LGM, 21-14-12 ka B.P.). The effects of permafrost on aeolian desertification are governed by numerous factors such as preceding and current climate conditions, locations of permafrost and aeolian sand activity, and trap conditions due to vegetation and topography.
DOI: 10.1016/j.quaint.2021.11.013
2022058575 Chang Xiaoli (Hunan University of Science and Technology, School of Earth Science and Spatial Information Engineering, Xiangtan, China); Jin Huijun; He Ruixia; Zhang Yanlin; Li Xiaoying; Jin Xiaoying and Li Guoyu. Permafrost changes in the northwestern Xiao Hinggan Ling, northeast China, in the past decade: Earth System Science Data (ESSD), 14(9), p. 3947-3959, illus. incl. 2 tables, geol. sketch map, 51 ref., 2022. Part of a special section entitled Extreme environment datasets for the three poles, edited by Carlson, D., et al.
Under a pronounced climate warming, permafrost has been degrading in most areas globally, but it is still unclear in the northwestern part of the Da Xing'anling Mountains, Northeast China. According to a 10-year observation of permafrost and active-layer temperatures, the multi-year average of mean annual ground temperatures at 20 m was -2.83, -0.94, -0.80, -0.70, -0.60, and -0.49°, respectively, at boreholes Gen'he4 (GH4), Mangui3 (MG3), Mangui1 (MG1), Mangui2 (MG2), Gen'he5 (GH5), and Yituli'he2 (YTLH2), with the depths of the permafrost table varying from 1.1 to 7.0 m. Ground cooling at shallow depths has been detected, resulting in declining thaw depths in Yituli'he during 2009-2020, possibly due to relatively stable mean positive air temperature and declining snow cover and a dwindling local population. In most study areas (e.g., Mangui and Gen'he), permafrost warming is particularly pronounced at larger depths (even at 80 m). These results can provide important information for regional development and engineering design and maintenance and also provide a long-term ground temperature dataset for the validation of models relevant to the thermal dynamics of permafrost in the Da Xing'anling Mountains. All of the datasets are published through the National Tibetan Plateau Data Center (TPDC), and the link is (Chang, 2021).
DOI: 10.5194/essd-14-3947-2022
2022063964 Heffernan, Liam (University of Alberta, Department of Renewable Resources, Edmonton, AB, Canada); Cavaco, Maria A.; Bhatia, Maya P.; Estop-Aragonés, Cristian; Knorr, Klaus-Holger and Olefeldt, David. High peatland methane emissions following permafrost thaw; enhanced acetoclastic methanogenesis during early successional stages: Biogeosciences, 19(12), p. 3051-3071, illus. incl. sketch map, 136 ref., 2022.
Permafrost thaw in northern peatlands often leads to increased methane (CH4) emissions, but the underlying controls responsible for increased emissions and the duration for which they persist have yet to be fully elucidated. We assessed how shifting environmental conditions affect microbial communities and the magnitude and stable isotopic signature (d13C) of CH4 emissions along a thermokarst bog transect in boreal western Canada. Thermokarst bogs develop following permafrost thaw when dry, elevated peat plateaus collapse and become saturated and dominated by Sphagnum mosses. We differentiated between a young and a mature thermokarst bog stage (~30 and ~200 years since thaw, respectively). The young bog located along the thermokarst edge was wetter, warmer, and dominated by hydrophilic vegetation compared to the mature bog. Using high-throughput 16S rRNA gene sequencing, we show that microbial communities were distinct near the surface and converged with depth, but fewer differences remained down to the lowest depth (160 cm). Microbial community analysis and d13C data from CH4 surface emissions and dissolved gas depth profiles show that hydrogenotrophic methanogenesis was the dominant pathway at both sites. However, mean d13C-CH4 signatures of both dissolved gas profiles and surface CH4 emissions were found to be isotopically heavier in the young bog (-63 ppm and -65 ppm, respectively) compared to the mature bog (-69 ppm and -75 ppm, respectively), suggesting that acetoclastic methanogenesis was relatively more enhanced throughout the young bog peat profile. Furthermore, mean young bog CH4 emissions of 82 mg CH4 m-2d-1 were ~3 times greater than the 32 mg CH4 m-2d-1 observed in the mature bog. Our study suggests that interactions between the methanogenic community, hydrophilic vegetation, warmer temperatures, and saturated surface conditions enhance CH4 emissions in young thermokarst bogs but that these favourable conditions only persist for the initial decades after permafrost thaw.
DOI: 10.5194/bg-19-3051-2022
2022058579 Palmtag, Juri (Stockholm University, Department of Human Geography, Stockholm, Sweden); Obu, Jaroslav; Kuhry, Peter; Richter, Andreas; Siewert, Matthias B.; Weiss, Niels; Westermann, Sebastian and Hugelius, Gustaf. A high spatial resolution soil carbon and nitrogen dataset for the northern permafrost region based on circumpolar land cover upscaling: Earth System Science Data (ESSD), 14(9), p. 4095-4110, illus. incl. 7 tables, 50 ref., 2022.
Soils in the northern high latitudes are a key component in the global carbon cycle; the northern permafrost region covers 22% of the Northern Hemisphere land surface area and holds almost twice as much carbon as the atmosphere. Permafrost soil organic matter stocks represent an enormous long-term carbon sink which is in risk of switching to a net source in the future. Detailed knowledge about the quantity and the mechanisms controlling organic carbon storage is of utmost importance for our understanding of potential impacts of and feedbacks on climate change. Here we present a geospatial dataset of physical and chemical soil properties calculated from 651 soil pedons encompassing more than 6500 samples from 16 different study areas across the northern permafrost region. The aim of our dataset is to provide a basis to describe spatial patterns in soil properties, including quantifying carbon and nitrogen stocks. There is a particular need for spatially distributed datasets of soil properties, including vertical and horizontal distribution patterns, for modeling at local, regional, or global scales. This paper presents this dataset, describes in detail soil sampling; laboratory analysis, and derived soil geochemical parameters; calculations; and data clustering. Moreover, we use this dataset to estimate soil organic carbon and total nitrogen storage estimates in soils in the northern circumpolar permafrost region (17.9´106 km2) using the European Space Agency's (ESA's) Climate Change Initiative (CCI) global land cover dataset at 300 m pixel resolution. We estimate organic carbon and total nitrogen stocks on a circumpolar scale (excluding Tibet) for the 0-100 and 0-300 cm soil depth to be 380 and 813 Pg for carbon, and 21 and 55 Pg for nitrogen, respectively. Our organic carbon estimates agree with previous studies, with most recent estimates of 1000 Pg (-170 to +186 Pg) to 300 cm depth. Two separate datasets are freely available on the Bolin Centre Database repository (URL: https://doi.org/10.17043/palmtag-2022-pedon-1, Palmtag et al., 2022a; and URL: https://doi.org/10.17043/palmtag-2022-spatial-1, Palmtag et al., 2002b).
DOI: 10.5194/essd-14-4095-2022
2022058573 Xia Zhuoxuan (Chinese University of Hong Kong, Earth System Science Programme, Hong Kong, China); Huang Lingcao; Fan Chengyan; Jia Shichao; Lin Zhanjun; Liu Lin; Luo Jing; Niu Fujun and Zhang Tingjun. Retrogressive thaw slumps along the Qinghai-Tibet engineering corridor; a comprehensive inventory and their distribution characteristics: Earth System Science Data (ESSD), 14(9), p. 3875-3887, illus. incl. 2 tables, geol. sketch map, 53 ref., 2022. Part of a special section entitled Extreme environment datasets for the three poles, edited by Carlon, D., et al.
The important Qinghai-Tibet Engineering Corridor (QTEC) covers the part of the Highway and Railway underlain by permafrost. The permafrost on the QTEC is sensitive to climate warming and human disturbance and suffers accelerating degradation. Retrogressive thaw slumps (RTSs) are slope failures due to the thawing of ice-rich permafrost. They typically retreat and expand at high rates, damaging infrastructure, and releasing carbon preserved in frozen ground. Along the critical and essential corridor, RTSs are commonly distributed but remain poorly investigated. To compile the first comprehensive inventory of RTSs, this study uses an iteratively semi-automatic method built on deep learning to delineate thaw slumps in the 2019 PlanetScope CubeSat images over a ~ 54000 km2 corridor area. The method effectively assesses every image pixel using DeepLabv3+ with limited training samples and manually inspects the deep-learning-identified thaw slumps based on their geomorphic features and temporal changes. The inventory includes 875 RTSs, of which 474 are clustered in the Beiluhe region, and 38 are near roads or railway lines. The dataset is available at URL: https://doi.org/10.5281/zenodo.6397029 (Xia et al., 2021a), with the Chinese version at DOI: URL: https://doi.org/10/11.888/Cryos.tpdc.272672 (Xia et al. 2021b). These RTSs tend to be located on north-facing slopes with gradients of 1.2-18.1° and distributed at medium elevations ranging from 4511 to 5212 m a.s.l. They prefer to develop on land receiving relatively low annual solar radiation (from 2900 to 3200 kWh-2), alpine meadow covered, and loam underlay. Our results provide a significant and fundamental benchmark dataset for quantifying thaw slump changes in this vulnerable region undergoing strong climatic warming and extensive human activities.
DOI: 10.5194/essd-14-3875-2022
2022058248 Li Jinlong (Chang'an University, School of Water and Environment, Xi'an, China); Wang Wei; Ke Xianmin; Li Jianhua; Yu Yating; Gao Zeyong and Niu Fujun. Impacts of groundwater flow on the evolution of a thermokarst lake in the permafrost-dominated region on the Qinghai-Tibet Plateau: Hydrological Processes, 35(12), Paper no. e14443, illus. incl. 2 tables, sketch map, 42 ref., December 2021.
As a result of global warming induced permafrost degradation in recent decades, thermokarst lakes in the Qinghai-Tibet plateau (QTP) have been regulating local hydrological and ecological processes. Simulations with coupled moisture-heat numerical models in the Beiluhe Basin (located in the hinterland of permafrost regions on the QTP) have provided insights into the interaction between groundwater flow and the freeze-thaw process. A total of 30 modified SUTRA scenarios were established to examine the effects of hydrodynamic forces, permeability, and climate on thermokarst lakes. The results indicate that the hydrodynamic condition variables regulate the permafrost degradation around the lakes. In case groundwater recharges to the lake, a low-temperature groundwater flow stimulates the expansion of the surrounding thawing regions through thermal convection. The thawing rate of the permafrost underlying the lake intensifies when groundwater is discharged from the lake. Under different permeability conditions, spatiotemporal variations in the active layer thickness significantly influence the occurrence of an open talik at the lake bottom. A warmer and wetter climate will inevitably lead to a sharp decrease in the upper limit of the surrounding permafrost, with a continual decrease in the duration of open talik events. Overall, our results underscore that comprehensive consideration of the relevant hydrologic processes is critical for improving the understanding of environmental and ecological changes in cold environments. Abstract Copyright (2022), John Wiley & Sons, Ltd.
DOI: 10.1002/hyp.14443
2022059231 Ran Youhua (Chinese Academy of Sciences, Northwest Institute of Eco-Environment and Resources, Lanzhou, China); Li Xin; Cheng Guodong; Nan Zhuotong; Che Jinxing; Sheng Yu; Wu Qingbai; Jin Huijun; Luo Dongliang; Tang Zhiguang and Wu Xiaobo. Mapping the permafrost stability on the Tibetan Plateau for 2005-2015: Science China. Earth Sciences, 64(1), p. 62-79, 95 ref., January 2021. Based on Publisher-supplied data.
Data scarcity is a major obstacle for high-resolution mapping of permafrost on the Tibetan Plateau (TP). This study produces a new permafrost stability distribution map for the 2010s (2005-2015) derived from the predicted mean annual ground temperature (MAGT) at a depth of zero annual amplitude (10-25 m) by integrating remotely sensed freezing degree-days and thawing degree-days, snow cover days, leaf area index, soil bulk density, high-accuracy soil moisture data, and in situ MAGT measurements from 237 boreholes on the TP by using an ensemble learning method that employs a support vector regression model based on distance-blocked resampled training data with 200 repetitions. Validation of the new permafrost map indicates that it is probably the most accurate of all currently available maps. This map shows that the total area of permafrost on the TP, excluding glaciers and lakes, is approximately 115.02 (105.47-129.59)´104 km2. The areas corresponding to the very stable, stable, semi-stable, transitional, and unstable types are 0.86´104, 9.62´104, 38.45´104, 42.29´104, and 23.80´104 km2, respectively. This new map is of fundamental importance for engineering planning and design, ecosystem management, and evaluation of the permafrost change in the future on the TP as a baseline.
DOI: 10.1007/s11430-020-9685-3
2022064295 Jacob, Klaus. Tauwetter im Permafrost [Thawing of permafrost]: MPG-Spiegel, 2021(4), p. 76-81, 2021.
URL: https://www.mpg.de/18156882/W005_Umwelt-Klima_076-081.pdf
2022061128 Sokolov, Kirill (Russian Academy of Sciences, Siberian Branch, Chersky Mining Institute of the North, Yakutsk, Russian Federation); Fedorova, Larisa and Fedorov, Maksim. Prospecting and evaluation of underground massive ice by ground-penetrating radar: Geosciences (Basel), 10(7), Article 274, illus., 56 ref., July 2020. Part of a special issue entitled Modern surveying and geophysical methods for soil and rock, edited by Kovacevic, M. S. and Bacic, M.
Data from geocryological studies of soil and rock massifs in permafrost zone are very important as a basis for predicting possible negative consequences associated with climate change. A promising technique for studying geocryological structures (various types of underground ice) is the ground-penetrating radar (GPR) method. This paper presents the applications of the GPR method to prospect and evaluate massive ice in a frozen rock mass. To study the features of GPR signals received during sounding of underground ice, a model of a single GPR trace for the structure "frozen rock-ice-frozen rock" was developed. As a result, regularities were established in the kinematic and dynamic characteristics of GPR signals at the upper and lower boundaries of massive ice, depending on its geometric parameters. The established features were confirmed by the results of computer and physical simulation of GPR measurements of a frozen rock mass model. The main result of the study was to obtain a set of criteria for identifying massive ice according to GPR measurements. The developed criteria will allow the use of GPR for a detailed study of the structure of permafrost rocks to prevent the development of dangerous cryogenic processes in undisturbed and urban areas of the Arctic.
DOI: 10.3390/geosciences10070274
2022062087 Turetsky, Merritt R. (University of Guelph, Department of Integrative Biology, Guelph, ON, Canada); Abbott, Benjamin W.; Jones, Miriam C.; Anthony, Katey Walter; Olefeldt, David; Schuur, Edward A. G.; Grosse, Guido; Kuhry, Peter; Hugelius, Gustaf; Koven, Charles; Lawrence, David M.; Gibson, Carolyn; Sannel, A. Britta K. and McGuire, A. David. Carbon release through abrupt permafrost thaw: Nature Geoscience, 13(2), p. 138-143, illus., 46 ref., February 2020.
DOI: 10.1038/s41561-019-0526-0
2022062178 Moska, Piotr (Silesian University of Technology, Institute of Physics, Center for Science and Education, Gliwice, Poland); Jary, Zdzislaw; Sokolowski, Robert Jan; Poreba, Grzegorz; Raczyk, Jerzy; Krawczyk, Marcin; Skurzynski, Jacek; Zielinski, Pawel; Michczynski, Adam; Tudyka, Konrad; Adamiec, Grzegorz; Piotrowska, Natalia; Pawelczyk, Fatima; Lopuch, Michal; Szymak, Agnieszka and Ryzner, Kamila. Chronostratigraphy of Late Glacial aeolian activity in SW Poland; a case study from the Niemodlin Plateau: Geochronometria, 47(1), p. 124-137, illus. incl. strat. col., 2 tables, sketch map, 85 ref., January 2020.
The stratigraphy of Late Pleniglacial and Late Glacial fluvio-to-aeolian succession was investigated in two sites located at the Niemodlin Plateau, SW Poland. Lithofacial analysis was used for the reconstruction of sedimentary environments. An absolute chronology for climatic change and the resulting environmental changes were determined based on optically stimulated luminescence (OSL - nine samples) and radiocarbon (three samples) dating methods. Four phases of changes in sedimentary environments were established. The first depositional phase correlates with the Last Permafrost Maximum (24-17 ka) based on the type and size of the periglacial structures, which aggraded under continuous permafrost conditions. During 17.5-15.5 ka (upper Late Pleniglacial), a stratigraphic gap was detected, owing to a break in the deposition on the interfluve area. The second depositional phase took place during 15.5-13.5 ka. During this phase, the first part of the dune formation (Przechód site) and fluvio-aeolian cover (Siedliska site) was deposited. The sedimentary processes continued throughout the entire Bolling interstadial and Older Dryas. In the third phase (Allerod interstadial), soil formation took place. At the Siedliska site, palaeosol represented Usselo soil type, whereas at the Przechod site, there was a colluvial type of soil. The last phase (Younger Dryas) is represented by the main phase of dune formation in both sites. After the Younger Dryas, no aeolian activity was detected. High compliance with both absolute dating methods was noticed.
DOI: 10.2478/geochr-2020-0015
2022062179 Nepop, R. K. (Russian Academy of Sciences, Siberian Branch, Institute of Geology and Mineralogy, Novosibirsk, Russian Federation); Agatova, A. R.; Bronnikova, M. A.; Zazovskaya, E. P.; Ovchinnikov, I. Yu. and Moska, P. Radiocarbon dating of organic rich deposits; difficulties of paleogeographical interpretations in highlands of Russian Altai: Geochronometria, 47(1), p. 138-153, illus. incl. sect., 2 tables, geol. sketch map, 55 ref., January 2020.
The high mountainous southeastern part of Russian Altai is characterized by complicated sedimentation history. As a result of tectonic movements, Paleogene, Neogene, and even more old Carboniferous and Jurassic organicrich deposits had been partly uplifted and exhumed on the ridge's slopes, where during the Pleistocene, they were affected by various exogenous processes including glaciation, glacio-fluvial erosion, winnowing activity of ice-dammed lakes, sliding during lake-draining events, followed by further intensive Holocene erosion, pedogenesis, and permafrost formation/degradation. Remobilized ancient organic matter had been involved into geomorphic and pedogenesis processes and affected the results of radiocarbon dating. Numerous radiocarbon ages obtained revealed several typical problems in interpretation of dating results, which was confirmed by multidisciplinary investigations of associated sediments in a wider regional context. This article presents a discussion on obtained apparent radiocarbon dates of organic material from ten sections of the SE Altai. In addition to radiocarbon analysis, in each case multidisciplinary study was carried out in order to properly interpret obtained dates, as well as to explain the inability of directly using apparent 14C ages as a geochronological basis for paleogeographical reconstruction. The analysis presented is of vital importance for establishing the chronology of formation of large ice-dammed lakes and their cataclysmic draining; revealing chronology and paleoenvironmental conditions of pedogenesis in the highlands of the SE Altai; and estimating the range and magnitude of the tectonically driven topography rebuilding in the post-Neogene time.
DOI: 10.2478/geochr-2020-0018
2022063883 Soto Molina, Víctor Hugo (Universidad Nacional Autónoma de México, Departamento de Vulcanologia, Coyoacan, Mexico) and Delgado Granados, Hugo. Distribution and current status of permafrost in the highest volcano in North America; Citlaltepetl (Pico de Orizaba), Mexico: Geofísica Internacional, 59(1), p. 39-53 (Spanish sum.), illus. incl. sketch map, 70 ref., January 2020.
The occurrence of permafrost in the Citlaltepetl volcano was emphasized and its coverage was updated. Through an empirical and statistical analysis of topo-climatic variables and based on linear regression it was found that the lower limit of continuous permafrost is positioned above 4,880 masl on its northern slope and at 4,963 on the southern slope; on the other hand, discontinuous and isolated patches start at 4,780 and 4,863 meters in the north and south respectively. A high correlation was found between the temperature of the ground profiles and the air temperature at their corresponding altitude. The temperature found in the permafrost classifies it as "warm" permafrost as in most mountains of medium and low latitude and at the same time it is classified as "compromised" and potentially unstable. In spite of the degradation observed from its first estimation during the 1970s, it is estimated that this indicator of climatic change in high mountains will remain at least for a few decades after the Citlaltepetl glacier has been extinguished.
URL: https://www.scielo.org.mx/pdf/geoint/v59n1/0016-7169-geoint-59-01-39.pdf
2022063394 Farzamian, Mohammad (Universidade de Lisboa, Faculdade de Ciencias, Lisbon, Portugal); Vieira, Goncalo; Santos, Fernando A. Monteiro; Tabar, Borhan Yaghoobi; Hauck, Christian; Paz, Maria Catarina; Bernardo, Ivo; Ramos, Miguel and de Pablo, Miguel Angel. Detailed detection of active layer freeze-thaw dynamics using quasi-continuous electrical resistivity tomography (Deception Island, Antarctica): The Cryosphere (Online), 14(3), p. 1105-1120, illus. incl. sketch maps, 44 ref., 2020.
Climate-induced warming of permafrost soils is a global phenomenon, with regional and site-specific variations which are not fully understood. In this context, a 2-D automated electrical resistivity tomography (A-ERT) system was installed for the first time in Antarctica at Deception Island, associated to the existing Crater Lake site of the Circumpolar Active Layer Monitoring - South Program (CALM-S) - site. This setup aims to (i) monitor subsurface freezing and thawing processes on a daily and seasonal basis and map the spatial and temporal variability in thaw depth and to (ii) study the impact of short-lived extreme meteorological events on active layer dynamics. In addition, the feasibility of installing and running autonomous ERT monitoring stations in remote and extreme environments such as Antarctica was evaluated for the first time. Measurements were repeated at 4 h intervals during a full year, enabling the detection of seasonal trends and short-lived resistivity changes reflecting individual meteorological events. The latter is important for distinguishing between (1) long-term climatic trends and (2) the impact of anomalous seasons on the ground thermal regime. Our full-year dataset shows large and fast temporal resistivity changes during the seasonal active layer freezing and thawing and indicates that our system setup can resolve spatiotemporal thaw depth variability along the experimental transect at very high temporal resolution. The largest resistivity changes took place during the freezing season in April, when low temperatures induce an abrupt phase change in the active layer in the absence of snow cover. The seasonal thawing of the active layer is associated with a slower resistivity decrease during October due to the presence of snow cover and the corresponding zero-curtain effect. Detailed investigation of the daily resistivity variations reveals several periods with rapid and sharp resistivity changes of the near-surface layers due to the brief surficial refreezing of the active layer in summer or brief thawing of the active layer during winter as a consequence of short-lived meteorological extreme events. These results emphasize the significance of the continuous A-ERT monitoring setup which enables detecting fast changes in the active layer during short-lived extreme meteorological events. Based on this first complete year-round A-ERT monitoring dataset on Deception Island, we believe that this system shows high potential for autonomous applications in remote and harsh polar environments such as Antarctica. The monitoring system can be used with larger electrode spacing to investigate greater depths, providing adequate monitoring at sites and depths where boreholes are very costly and the ecosystem is very sensitive to invasive techniques. Further applications may be the estimation of ice and water contents through petrophysical models or the calibration and validation of heat transfer models between the active layer and permafrost.
DOI: 10.5194/tc-14-1105-2020
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The USPA is pleased to announce the availability of an updated searchable database on permafrost-related publications. The American Geosciences Institute (AGI), with support from the National Science Foundation (NSF), has migrated the previous Cold Regions Bibliography to a new platform. Included are the USPA supported PMAs dating back to 2011. The Bibliography is searchable at 
