Permafrost Monthly Alerts (PMAs)

2021029033 Lindgren, Prajna R. (University of Alaska Fairbanks, Geophysical Institute, Fairbanks, AK); Farquharson, Louise M.; Romanovsky, Vladimir E. and Grosse, Guido. Landsat-based lake distribution and changes in western Alaska permafrost regions between the 1970s and 2010s: Environmental Research Letters, 16(2), Paper no. 025006, illus. incl. 2 tables, 30 ref., February 2021.

Lakes are an important ecosystem component and geomorphological agent in northern high latitudes and it is important to understand how lake initiation, expansion and drainage may change as high latitudes continue to warm. In this study, we utilized Landsat Multispectral Scanner System images from the 1970s (1972, 1974, and 1975) and Operational Land Imager images from the 2010s (2013, 2014, and 2015) to assess broad-scale distribution and changes of lakes larger than 1 ha across the four permafrost zones (continuous, discontinuous, sporadic, and isolated extent) in western Alaska. Across our 68 000 km² study area, we saw a decline in overall lake coverage across all permafrost zones with the exception of the sporadic permafrost zone. In the continuous permafrost zone lake area declined by -6.7% (-65.3 km²), in the discontinuous permafrost zone by -1.6% (-55.0 km²), in the isolated permafrost zone by -6.9% (-31.5 km²) while lake cover increased by 2.7% (117.2 km²) in the sporadic permafrost zone. Overall, we observed a net drainage of lakes larger than 10 ha in the study region. Partial drainage of these medium to large lakes created an increase in the area covered by small water bodies <10 ha, in the form of remnant lakes and ponds by 7.1% (12.6 km²) in continuous permafrost, 2.5% (15.5 km²) in discontinuous permafrost, 14.4% (74.6 km²) in sporadic permafrost, and 10.4% (17.2 km²) in isolated permafrost. In general, our observations indicate that lake expansion and drainage in western Alaska are occurring in parallel. As the climate continues to warm and permafrost continues to thaw, we expect an increase in the number of drainage events in this region leading to the formation of higher numbers of small remnant lakes. Copyright (Copyright) 2021 The Author(s). Published by IOP Publishing Ltd.

DOI: 10.1088/1748-9326/abd270

2021029035 MacDonald, Erin N. (University of Alberta, Department of Biological Sciences, Edmonton, AB, Canada); Tank, Suzanne E.; Kokelj, Steven V.; Froese, Duane G. and Hutchins, Ryan H. S. Permafrost-derived dissolved organic matter composition varies across permafrost end-members in the western Canadian Arctic: Environmental Research Letters, 16(2), Paper no. 024036, illus. incl. 3 tables, sketch map, 30 ref., February 2021.

Organic matter, upon dissolution into the aqueous state as dissolved organic matter (DOM), can undergo mineralization by microbes. There has been increasing effort to characterize DOM released from thawing permafrost because it may perpetuate a permafrost carbon feedback. Permafrost-derived DOM often has a composition that can be highly susceptible to mineralization by microbes, but most studies to date that characterize permafrost-derived DOM have been limited to select regions, and tend to focus on a single type of permafrost (sometimes unspecified) that reflects a particular deposit type. Importantly, diversity in the nature of the deposit, formation of permafrost, and thaw modification processes leads to spatial and stratigraphic variability in its properties, but our understanding of variation in the composition of DOM derived from differing permafrost types (end-members) is poor. Here, we used ultrahigh-resolution mass spectrometry to characterize DOM composition derived from a series of permafrost end-member types that are commonly found within the thaw-vulnerable western Canadian Arctic, including: tills (glacially deposited), diamicton (thawed and remobilized material of mixed origin), lacustrine (lake basin sediments into which permafrost has aggraded), peat (partially decomposed organic material), and Yedoma (syngenetic silty loess) deposits. We identified marked variation in DOM composition among permafrost end-member types. Tills were compositionally dissimilar to all other permafrost end-members. Compounds unique to Yedoma were predominantly aliphatic, while compounds unique to peat, lacustrine, and diamicton spanned saturation and oxygenation gradients. All permafrost leachates were generally higher in aliphatics, lower in aromatics, and less oxygenated than active layer leachates. Compositional differences appear to reflect variation in permafrost parent materials, and particularly strong effects from past modification processes while in the unfrozen or thawed state. Constraining DOM composition and assessing its stratigraphic variability will become more pressing as the spatial and stratigraphic extent of thaw increases with future warming. Copyright (Copyright) 2021 The Author(s). Published by IOP Publishing Ltd.

DOI: 10.1088/1748-9326/abd971

2021029036 Mekonnen, Zelalem A. (Lawrence Berkeley National Laboratory, Climate and Ecosystem Sciences Division, Berkeley, CA); Riley, William J.; Grant, Robert F. and Romanovsky, Vladimir E. Changes in precipitation and air temperature contribute comparably to permafrost degradation in a warmer climate: Environmental Research Letters, 16(2), Paper no. 024008, illus., 40 ref., February 2021.

Surface energy budgets of high-latitude permafrost systems are poorly represented in Earth system models (ESMs), yet permafrost is rapidly degrading and these dynamics are critical to future carbon-climate feedback predictions. A potentially important factor in permafrost degradation neglected so far by ESMs is heat transfer from precipitation, although increases in soil temperature and thaw depth have been observed following increases in precipitation. Using observations and a mechanistic ecosystem model, we show here that increases in precipitation hasten active layer development beyond that caused by surface air warming across the North Slope of Alaska (NSA) under recent and 21st century climate (RCP8.5). Modeled active layer depth (ALD) in simulations that allow precipitation heat transfer agreed very well with observations from 28 Circumpolar Active Layer Monitoring sites (R² = 0.63; RMSE = 10 cm). Simulations that ignored precipitation heat transfer resulted in lower spatially-averaged soil temperatures and a 39 cm shallower ALD by 2100 across the NSA. The results from our sensitivity analysis show that projected increases in 21st century precipitation deepen the active layer by enhancing precipitation heat transfer and ground thermal conductivity, suggesting that precipitation is as important an environmental control on permafrost degradation as surface air temperature. We conclude that ESMs that do not account for precipitation heat transfer likely underestimate ALD rates of change, and thus likely predict biased ecosystem responses. Copyright (Copyright) 2021 The Author(s). Published by IOP Publishing Ltd.

DOI: 10.1088/1748-9326/abc444

2021032261 Mishra, Umakant (Argonne National Laboratory, Environmental Science Division, Argonne, IL); Hugelius, Gustaf; Shelef, Eitan; Yang Yuanhe; Strauss, Jens; Lupachev, Alexey; Harden, Jennifer W.; Jastrow, Julie D.; Ping, Chien-Lu; Riley, William J.; Schuur, Edward A. G.; Matamala, Roser; Siewert, Matthias; Nave, Lucas E.; Koven, Charles D.; Fuchs, Matthias; Palmtag, Juri; Kuhry, Peter; Treat, Claire C.; Zubrzycki, Sebastian; Hoffman, Forrest M.; Elberling, Bo; Camill, Philip; Veremeeva, Alexandra and Orr, Andrew. Spatial heterogeneity and environmental predictors of permafrost region soil organic carbon stocks: Science Advances, 7(9), Paper no. eaaz5236, illus. incl. 2 tables, 40 ref., February 24, 2021.

DOI: 10.1126/sciadv.aaz5236

2021029030 Zhao Rui (Southwest Jiaotong University, Chengdu, China); Yao Mingxing; Yang Linchuan; Qi Hua; Meng Xianglian and Zhou Fujun. Using geographically weighted regression to predict the spatial distribution of frozen ground temperature; a case in the Qinghai-Tibet Plateau: Environmental Research Letters, 16(2), Paper no. 024003, illus. incl. 2 tables, sketch map, 40 ref., February 2021.

This paper combines the use of principal component analysis (PCA) and the geographically weighted regression (GWR) model to predict the spatial distribution of frozen ground temperature. PCA is used to reduce the multicollinearity among covariates, while the GWR model is used to address the spatially non-stationary relationship between frozen ground temperature and its predictors, such as air temperature, latitude, longitude, and vegetation cover. Our approach is applied in a typical permafrost area in the Qinghai-Tibet Plateau, Western China. The result demonstrates the applicability of our approach in the spatial distribution of frozen ground temperature and shows that the approach can be used for analysis and prediction. This study offers insight into temperature monitoring of frozen ground, which helps prevent regional geological disasters. Copyright (Copyright) 2021 The Author(s). Published by IOP Publishing Ltd.

DOI: 10.1088/1748-9326/abd431

2021031615 Hu Tianfei (Shijiazhuang Tiedao University, State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures, Shijiazhuang, China); Liu Jiankun; Chang Jian and Hao Zhonghua. Development of a novel vapor compression refrigeration system (VCRS) for permafrost cooling: Cold Regions Science and Technology, 181, Paper no. 103173, illus. incl. 3 tables, January 2021. Based on Publisher-supplied data.

To address the higher cooling requirement for embankments in permafrost regions, a novel active refrigerating method, which focuses on releasing permafrost heat in warm seasons, is presented. Based on the real situations in field, comparisons were made between thermally driven and electrically driven refrigeration methods in the roadway application. A prototype of the vapor compression refrigeration system (VCRS) was then designed and manufactured, and its practical performance experimentally investigated. The data shows that: (1) the refrigerating temperature can reach below 0°C in warm seasons; (2) the heat reflux capacity and effective coefficient of performance is about 55.4 W and 0.41, respectively; (3) the predicted long term cooling scope is more than 6 m. The VCRS prototype can present good refrigerating performance in warm seasons. We conclude that the new structure is a potential method for preventing permafrost degradation and can ensure the long-term thermal stability of embankments under the effects of climate warming.

DOI: 10.1016/j.coldregions.2020.103173

2021028947 Shakil, S. (University of Alberta, Department of Biological Sciences, Edmonton, AB, Canada); Tank, S. E.; Kokelj, S. V.; Vonk, J. E. and Zolkos, S. Particulate dominance of organic carbon mobilization from thaw slumps on the Peel Plateau, NT; quantification and implications for stream systems and permafrost carbon release: Environmental Research Letters, 15(11), p. Paper no. 114019, illus. incl. 3 tables, sketch map, 30 ref., November 2020.

Climate change is increasing the frequency and intensity of thermokarst, and accelerating the delivery of terrestrial organic material from previously sequestered sources to aquatic systems, where it is subject to further biochemical alteration. Rapid climate change in the glacially conditioned ice-rich and ice-marginal terrain of the Peel Plateau, western Canada, is accelerating thaw-driven mass wasting in the form of retrogressive thaw slumps, which are rapidly increasing in area, volume and thickness of permafrost thawed. Despite major perturbation of downstream sedimentary and geochemical fluxes, few studies have examined changes in flux and composition of particulate organic carbon (POC) in streams and rivers as a result of permafrost thaw. Here we show that the orders of magnitude increase in total organic carbon, nitrogen, and phosphorus mobilized to streams from thaw slumps on the Peel Plateau is almost entirely due to POC and associated particulate nitrogen and phosphorus release. Slump-mobilized POC is compositionally distinct from its dissolved counterpart and appears to contain relatively greater amounts of degraded organic matter, as inferred from base-extracted fluorescence of particulate organic matter. Thus, slump-mobilized POC is potentially more recalcitrant than POC present in non-slump affected stream networks. Furthermore a substantial portion of POC mobilized from thaw slumps will be constrained within primary sediment stores in valley bottoms, where net accumulation is currently exceeding net erosion, resulting in century to millennial scale sequestration of thermokarst-mobilized POC. This study highlights the pressing need for better knowledge of sedimentary cascades, mobilization, and storage reservoirs in slump-affected streams, and baseline assessments of the biodegradability of POC and cycling of particulate nutrients within a sedimentary cascade framework. Explicit incorporation of POC dynamics into our understanding of land-water carbon mobilization in the face of permafrost thaw is critical for understanding implications of thermokarst for regional carbon cycling and fluvial ecosystems. Copyright (Copyright) 2020 The Author(s). Published by IOP Publishing Ltd.

DOI: 10.1088/1748-9326/abac36

2021028952 Williams, Mathew (University of Edinburgh, School of GeoSciences, Edinburgh, United Kingdom); Zhang, Yu; Estop-Aragonés, Cristian; Fisher, James P.; Xenakis, Georgios; Charman, Dan J.; Hartley, Iain P.; Murton, Julian B. and Phoenix, Gareth K. Boreal permafrost thaw amplified by fire disturbance and precipitation increases: Environmental Research Letters, 15(11), Paper no. 114050, illus. incl. 3 tables, 40 ref., November 2020.

Permafrost soils store huge amounts of organic carbon, which could be released if climate change promotes thaw. Currently, modelling studies predict that thaw in boreal regions is mainly sensitive to warming, rather than changes in precipitation or vegetation cover. We evaluate this conclusion for North American boreal forests using a detailed process-based model parameterised and validated on field measurements. We show that soil thermal regimes for dominant forest types are controlled strongly by soil moisture and thus the balance between evapotranspiration and precipitation. Under dense canopy cover, high evapotranspiration means a 30% increase in precipitation causes less thaw than a 1 °C increase in temperature. However, disturbance to vegetation promotes greater thaw through reduced evapotranspiration, which results in wetter, more thermally conductive soils. In such disturbed forests, increases in precipitation rival warming as a direct driver of thaw, with a 30% increase in precipitation at current temperatures causing more thaw than 2 °C of warming. We find striking non-linear interactive effects on thaw between rising precipitation and loss of leaf area, which are of concern given projections of greater precipitation and disturbance in boreal forests. Inclusion of robust vegetation-hydrological feedbacks in global models is therefore critical for accurately predicting permafrost dynamics; thaw cannot be considered to be controlled solely by rising temperatures. Copyright (Copyright) 2020 The Author(s). Published by IOP Publishing Ltd.

DOI: 10.1088/1748-9326/abbeb8

2021032260 Chen, Jingyi (University of Texas at Austin, Department of Aerospace Engineering and Engineering Mechanics, Austin, TX); Wu, Yue; O'Connor, Michael; Cardenas, M. Bayani; Schaefer, Kevin; Michaelides, Roger and Kling, George. Active layer freeze-thaw and water storage dynamics in permafrost environments inferred from InSAR: Remote Sensing of Environment, 248, Paper no. 112007, October 2020. Based on Publisher-supplied data.

DOI: 10.1016/j.rse.2020.112007

2021032259 Wang Lingxiao (Nanjing University of Information Science and Technology, School of Geographical Sciences, Nanjing, China); Marzahn, Philip; Bernier, Monique and Ludwig, Ralf. Sentinel-1 InSAR measurements of deformation over discontinuous permafrost terrain, northern Quebec, Canada: Remote Sensing of Environment, 248, Paper no. 111965, illus. incl. 2 tables, geol. sketch map, October 2020. Based on Publisher-supplied data; includes appendix.

DOI: 10.1016/j.rse.2020.111965

2021026910 Grotheer, H. (Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research, Bremerhaven, Germany); Meyer, V.; Riedel, T.; Pfalz, G.; Mathieu, L.; Hefter, J.; Gentz, T.; Lantuit, H.; Mollenhauer, G. and Fritz, M. Burial and origin of permafrost-derived carbon in the nearshore zone of the southern Canadian Beaufort Sea: Geophysical Research Letters, 47(3), Article e2019GL085897, illus. incl. sketch maps, 69 ref., February 16, 2020.

Detailed organic geochemical and carbon isotopic (d¹³C and D¹⁴C) analyses are performed on permafrost deposits affected by coastal erosion (Herschel Island, Canadian Beaufort Sea) and adjacent marine sediments (Herschel Basin) to understand the fate of organic carbon in Arctic nearshore environments. We use an end-member model based on the carbon isotopic composition of bulk organic matter to identify sources of organic carbon. Monte Carlo simulations are applied to quantify the contribution of coastal permafrost erosion to the sedimentary carbon budget. The models suggest that ~40% of all carbon released by local coastal permafrost erosion is efficiently trapped and sequestered in the nearshore zone. This highlights the importance of sedimentary traps in environments such as basins, lagoons, troughs, and canyons for the carbon sequestration in previously poorly investigated, nearshore areas. Abstract Copyright (2019), The Authors.

DOI: 10.1029/2019GL085897

2021032333 Chuvilin, Evgeny (Skolkovo Institute of Science and Technology (Skoltech), Center for Hydrocarbon Recovery, Moscow, Russian Federation); Sokolova, Natalia; Davletshina, Dinara; Bukhanov, Boris; Stanilovskaya, Julia; Badetz, Christian and Spasennykh, Mikhail. Conceptual models of gas accumulation in the shallow permafrost of northern West Siberia and conditions for explosive gas emissions: Geosciences (Basel), 10(5), Article 195, illus. incl. sects., 52 ref., 2020. Part of a special issue entitled Gas emissions and crater formation in the Arctic permafrost, edited by Chuvilin, E.

Gas accumulation and pressurized unfrozen rocks under lakes (sublake taliks) subject to freezing in shallow permafrost may lead to explosive gas emissions and the formation of craters. Gas inputs into taliks may have several sources: microbially-mediated recycling of organic matter, dissociation of intrapermafrost gas hydrates, and migration of subpermafrost and deep gases through permeable zones in a deformed crust. The cryogenic concentration of gas increases the pore pressure in the freezing gas-saturated talik. The gradual pressure buildup within the confined talik causes creep (ductile) deformation of the overlying permafrost and produces a mound on the surface. As the pore pressure in the freezing talik surpasses the permafrost strength, the gas-water-soil mixture of the talik erupts explosively and a crater forms where the mound was. The critical pressure in the confined gas-saturated talik (2-2.5 MPa for methane) corresponds to the onset of gas hydrate formation. The conditions of gas accumulation and excess pressure in freezing closed taliks in shallow permafrost, which may be responsible for explosive gas emissions and the formation of craters, are described by several models.

DOI: 10.3390/geosciences10050195

2021032334 Chuvilin, Evgeny (Skolkovo Innovation Center, Skolkovo Institute of Science and Technology (Skoltech), Center for Hydrocarbon Recovery, Moscow, Russian Federation); Stanilovskaya, Julia; Titovsky, Aleksey; Sinitsky, Anton; Sokolova, Natalia; Bukhanov, Boris; Spasennykh, Mikhail; Cheremisin, Alexey; Grebenkin, Sergey; Davletshina, Dinara and Badetz, Christian. A gas-emission crater in the Erkuta River valley, Yamal Peninsula; characteristics and potential formation model: Geosciences (Basel), 10(5), Article 170, illus. incl. 5 tables, sketch map, 23 ref., 2020. Part of a special issue entitled Gas emissions and crater formation in Arctic permafrost, edited by Chuvilin, E.

Methane is a powerful greenhouse gas, and the abrupt degassing events that recently have formed large craters on the Russian Arctic Yamal and Gydan Peninsulas have caused major concern. Here we present field data on cover sediments and evolution of a gas-emission crater discovered in the Erkuta-Yakha River valley in the southern Yamal Peninsula in June 2017. The crater is located south of other similar craters discovered over the past decade in northern West Siberia. Data were collected during a field trip to the Erkuta crater in December 2017 which included field observations and sampling of permafrost soil and ground ice from the rim of the crater. All soil and ice samples were measured for contents of methane and its homologs (ethane and propane) and carbon dioxide. The contents of carbon dioxide in some samples are notably higher than methane. The strongly negative d¹³S of methane from ground ice samples (-72 ppm) is typical of biogenic hydrocarbons. The ratio of methane to the total amount of its homologs indicate a component of gases that have migrated from a deeper, thermogenic source. Based on obtained results, a potential formation model for Erkuta gas-emission crater is proposed, which considers the combined effect of deep-seated (deep gas migration) and shallow (oxbow lake evolution and closed talik freezing) causes. This model includes several stages from geological prerequisites to the lake formation.

DOI: 10.3390/geosciences10050170

2021032318 Dobinski, Wojciech (University of Silesia in Katowice, Institute of Earth Sciences, Faculty of Natural Science, Sosnowiec, Poland). The occurrence of permafrost within the glacial domain: Geosciences (Basel), 10(5), Article 193, illus. incl. sect., 46 ref., 2020. Part of a special issue entitled Permafrost and glaciers; perspectives for the earth and planetary sciences, edited by Dobinksi, W. and Kneisel, C.

The occurrence of permafrost within glacial environments has never been comprehensively defined based on scientific evidence, despite its importance in determining how all the components of the cryosphere associate and interact. Here, the relation between glaciers and permafrost is discussed based on what scientific field they have been traditionally associated with. As the most accepted definition of permafrost is not exclusively linked to the presence of a geological medium, this can also be ice of any origin, including snow and glacial ice. Thus, active glaciers can act as permafrost medium. Indeed, all thermal types of glaciers meet the definition of permafrost as they remain at or below 0°C for certainly more than two consecutive years. Active rock glaciers, regardless of the origin of the ice within, also meet the definition of permafrost. The presence of an active layer is not a prerequisite for the existence of permafrost either. Therefore, a comprehensive definition of permafrost occurrence across the cryosphere is essential to appropriately understand the phenomenon as a whole, not only as seen from our planet but also as it occurs for example on the icy moons of the Solar System and other frozen rocky bodies.

DOI: 10.3390/geosciences10050193

2021032311 Pavlova, Nadezhda (Melnikov Permafrost Institute of the Siberian Branch of Russian Academy of Sciences, Yakutsk, Russian Federation); Ogonerov, Vasily; Danzanova, Marina and Popov, Vladimir. Hydrogeology of reclaimed floodplain in a permafrost area, Yakutsk, Russia: Geosciences (Basel), 10(5), Article 192, illus. incl. sects., 2 tables, geol. sketch map, 44 ref., 2020. Part of a special issue entitled Groundwater flow assessment, edited by Gattinoni, P.

A study was performed to evaluate the current permafrost and groundwater conditions in the reclaimed floodplain of the Lena, one of the largest rivers in the permafrost zone. Data from ongoing hydrogeological monitoring were compared with earlier observations conducted during the reclamation process. The results demonstrate that the placement of dredged fill led to the development of suprapermafrost thaw zones (taliks). The anthropogenic taliks vary in thickness from 10 to 15 m in areas of buried bars to 20 m or more in the former locations of oxbow lakes. There is similarity in seasonal groundwater fluctuation patterns and response to river stage variations across the study area suggesting that a continuous aquifer connected to surface water. The connection with the river is most evident during the spring flood period. Two mechanisms of ground saturation are identified during this time. One is lateral seepage flow from the Lena River into the fill mass. The zone of its influence is limited to 150-170 m from the stream. The second is hydraulic pressure transmission from the river through the subchannel flow connected with the anthropogenic suprapermafrost aquifer. Its influence extends across the entire fill area. Continuous water movement at the base of the fill prevents permafrost aggradation from below. The study results should be taken into account when developing and implementing design and construction standards for engineering structures in the reclaimed floodplains of the permafrost zone.

DOI: 10.3390/geosciences10050192

2021032321 Szafraniec, Joanna Ewa (University of Silesia in Katowice, Institute of Earth Sciences, Faculty of Natural Sciences, Sosnowiec, Poland) and Dobinski, Wojciech. Deglaciation rate of selected nunataks in Spitsbergen, Svalbard; potential for permafrost expansion above the glacial environment: Geosciences (Basel), 10(5), Article 202, illus. incl. 2 tables, sketch maps, 77 ref., 2020. Part of a special issue entitled Permafrost and glaciers; perspectives for the earth and planetary sciences, edited by Dobinski, W. and Kneisel, C.

Spitsbergen has recently experienced a continuous deglaciation process, linked to both glacier front retreat and lowering of the glacier surface. This process is accompanied by permafrost aggradation from the top of the slopes down to the glacier. Here, the authors determine the rate of permafrost expansion in this type of vertical profile. To this end, seven nunataks across the island were analysed using Landsat satellite imagery, a high-resolution digital elevation model (ArcticDEM), and geoinformation software. Over the last 24-31 years, new nunataks gradually emerged from the ice cover at an average linear rate of 0.06 m a^-1 per degree of increment of the slope of the terrain at an average altitude of approximately 640 m a.s.l. The analysis showed that the maximum rate of permafrost expansion down the slope was positively correlated with the average nunatak elevation, reaching a value of approximately 10,000 m² a^-1. In cold climates, with a mean annual air temperature (MAAT) below 0°C, newly exposed land is occupied by active periglacial environments, causing permafrost aggradation. Therefore, both glacial and periglacial environments are changing over time concomitantly, with permafrost aggradation occurring along and around the glacier, wherever the MAAT is negative.

DOI: 10.3390/geosciences10050202

2021032299 Yakushev, Vladimir (Gubkin University of Oil and Gas, Gas Fields Development Department, Moscow, Russian Federation). Natural gas liberations around production wells at Russian Arctic gas fields: Geosciences (Basel), 10(5), Article 184, illus. incl. 2 tables, sketch map, 19 ref., 2020. Part of a special issue entitled Gas emissions and crater formation in Arctic permafrost, edited by Chuvilin, E., et al.

Gas samples from gas liberations around wellheads on two giant natural gas fields in West Siberia (Bovanenkovo and Yamburg) have been tested for their carbon isotopic and molecular compositions. Results have shown local, microbial genesis of gas and that its source is permafrost at both gas fields. Gas liberation is caused by permafrost rock massif thawing around working well. Gas liberations can appear at different distances from the casing inside the radius of thawing. Two gas samples taken from gas liberations at casing border have shown thermogenic origin, which was explained by deep gas leakage through the casing. Gas liberations from deep production horizons are few, and they concentrate around the casing. Permafrost gas liberations are numerous, and they are spread at different distances from the wellhead.

DOI: 10.3390/geosciences10050184

2021031817 Chen Donggen (CCCC First Highway Consultants Company, Xi'ai, China); Wang Shuangjie; Zhang, Xiong; Chen Jianbing and Jin Long. Experimental study on performance of crushed-rock embankment with heat-induced asphalt pavement: Transportation Geotechnics, 21, Paper no. 100270, illus. incl. 5 tables, December 2019. Based on Publisher-supplied data.

Previous numerical and field studies have confirmed effectiveness of the crushed-rock embankment (CRE) in protecting permafrost foundations in cold regions. However, some recent field monitoring data indicated that the CRE was not effective enough to prevent the permafrost foundations from thawing in some highway applications. The undermined effectiveness of the CRE was attributed to the strong heat absorption associated with the black asphalt pavement which absorbed more heat compared with lighter-colored surfaces. In order to strengthen the cooling effect of CRE in highway application, the composite CRE section with the heat-induced asphalt pavement (the composite CRE section) was presented. And then, the indoor laboratory model tests were performed to investigate the cooling performances of two sections: one is the composite CRE section, the other is the control CRE section with the conventional asphalt pavement (the control CRE section). Various sensors were installed at different locations of the two test sections to monitor the temperature, wind speed, and heat flux in order to better understand the working mechanisms of the different CRE structures. The test results showed that: (1) the heat-induced asphalt pavement increased the heat release in cold cycles, which was conducive to generate natural convection of the CRE. The cooling effect of the composite CRE section on the foundation was better than that of the control CRE section. (2) The maximum velocity of natural convection of crushed-rock layer in the composite CRE section was bigger than that of the control CRE section. The duration of the convection stage in the composite CRE section was longer than that of the control CRE section. (3) In warming cycles, the heat flux in the composite CRE section was slightly larger than that in the control CRE section. In cooling cycles, the heat flux in the composite CRE section was much smaller than that in the control CRE section. By comparing the cooling effects, air convective characteristics, and transient heat flux in the two CRE sections, the composite CRE section has a good cooling effects comparing with the control CRE section.

DOI: 10.1016/j.trgeo.2019.100270

2021031829 Ma Wei (Chinese Academy of Sciences, Northwest Institute of Eco-Environment and Resources, Lanzhou, China); Mu Yanhu; Zhang Jianming; Yu Wenbing; Zhou Zhiwei and Chen Tuo. Lateral thermal influences of roadway and railway embankments in permafrost zones along the Qinghai-Tibet engineering corridor: Transportation Geotechnics, 21, Paper no. 100285, illus. incl. sketch map, December 2019. Based on Publisher-supplied data; includes appendix.

In permafrost zones, the ground thermal regime beneath and around foundations is of great importance to long-term stability and integrity of engineering infrastructures. In this study, ground temperatures beneath and around embankments of the Qinghai-Tibet Highway (QTH) and the Qinghai-Tibet Railway (QTR) were observed at two profiles in continuous permafrost zones on the Qinghai-Tibet Plateau. The lateral thermal influences of the embankments on natural ground in the vicinity were analyzed based on the field observed data. The results indicated that the lateral thermal influence of the QTH and QTR embankments on shallow ground in the vicinity was very slight. The permafrost table depth or freeze-thaw process in the shallow ground near the embankments was mainly determined by the ground surface conditions. Different from the case of shallow ground, the lateral thermal influence of the QTH embankment on the permafrost in the vicinity was significant. Based on the permafrost temperature distribution at -10 m depth, the scopes of the lateral thermal influence of the QTH embankment calculated from the embankment shoulder were as much as 30-40 m at the two observation profiles. Whereas, the lateral thermal influence of the QTR embankment on the permafrost in the vicinity was slight. Because the QTR was constructed using cooling method of crushed rock embankment at the two profiles, the underlying permafrost either maintained well in thermal regime or experienced a slight cooling. The factors affecting the scope of the lateral thermal influences of embankments on permafrost in the vicinity were discussed at the end of the paper, as well as the related mitigation method. This study provides information that could aid engineering design of linear transportation projects and the assessment of environmental impacts in permafrost zones.

DOI: 10.1016/j.trgeo.2019.100285

2021031819 Moussa, Ahmed (University of Manitoba, Department of Civil Engineering, Winnipeg, MB, Canada); Kavanagh, Leonnie and Shalaby, Ahmed. Boundary conditions for modeling the ground thermal profile near shallow culverts: Transportation Geotechnics, 21, Paper no. 100272, illus. incl. 5 tables, December 2019. Based on Publisher-supplied data; includes appendix.

Culverts create disturbance in the ground thermal regime in cold regions below pavement structures. The thermal disturbance caused by culverts may result in geotechnical problems such as permafrost degradation, frost heave, and differential settlement which impact road roughness and road safety. Thermal numerical modeling of shallow culverts below a pavement structure requires accurately defining boundary conditions for the road surface. This study evaluates five empirical pavement temperature methods used as the pavement surface boundary condition in a 2D numerical model that predicts the soil temperature below pavement surfaces over shallow culverts. The predicted soil temperatures from the numerical model are validated with two years of measured soil temperatures at five instrumented culvert sites. The predicted soil temperatures are evaluated through trend analysis and statistical F-test at 95% confidence. A pavement surface boundary condition obtained from each of the five pavement temperature methods is considered successful when the difference between the predicted and measured values pass the F-test for all seasons over the two-year study period. The results of the analysis show that three of the five pavement temperature methods passed the trend and F-test analysis. The three pavement temperature methods more accurately defines the boundary conditions for the road surface and are utilized in the numerical model to predicted frost penetration depth below the pavement surface and near the culvert openings. The findings from this study are expected to increase the accuracy of modeling the frost heave and the differential thaw settlement under pavement structure due to the influence of culverts.

DOI: 10.1016/j.trgeo.2019.100272

2021031816 Wu Zhijian (Nanjing Tech University, College of Transportation Science and Engineering, Nanjing, China); Zhang Dan; Zhao Tao; Ma Jinlian and Zhao Duoyin. An experimental research on damping ratio and dynamic shear modulus ratio of frozen silty clay of the Qinghai-Tibet engineering corridor: Transportation Geotechnics, 21, Paper no. 100269, illus. incl. 4 tables, sketch map, December 2019. Based on Publisher-supplied data; includes appendix.

Strong earthquakes occurred frequently in Qinghai-Tibet Plateau. Major national infrastructure facilities, including existing and proposed projects, are located densely in the permafrost engineering corridor of Qinghai-Tibet Plateau. Based on dynamic triaxial test under the effect of cycle loading for remolded frozen soil taken from Qinghai-Tibet engineering corridor, experimental studies on the influence of confining pressure, temperature, moisture content and frequency on damping ratio and dynamic shear modulus ratio have been carried out systematically. The results are summarized as follows: The damping ratio of frozen Qinghai-Tibet silty clay increases with increasing in confining pressure, temperature and water content, and decreasing in frequency. In addition, the dynamic shear modulus ratio reduces with increasing in confining pressure, temperature and water content, and decreasing in frequency. The relationship equation between the maximum dynamic shear modulus of frozen silty clay and temperature, water content and confining pressure is obtained by using multivariate non-linear fitting method, which shows a better fitting effect. The results of this research can provide basic data for the design of major engineering and seismic fortification along Qinghai-Tibet engineering corridor.

DOI: 10.1016/j.trgeo.2019.100269

2021029858 Matthews, John A. (Swansea University, Department of Geography, Swansea, United Kingdom); Wilson, Peter; Winkler, Stefan; Mourne, Richard W.; Hill, Jennifer L.; Owen, Geraint; Hiemstra, John F.; Hallang, Helen and Geary, Andrew P. Age and development of active cryoplanation terraces in the alpine permafrost zone at Svartkampan, Jotunheimen, southern Norway: Quaternary Research, 92(3), p. 641-664, illus. incl. sects., 5 tables, sketch maps, 122 ref., November 2019.

Schmidt-hammer exposure-age dating (SHD) of boulders on cryoplanation terrace treads and associated bedrock cliff faces revealed Holocene ages ranging from 0 ± 825 to 8890 ± 1185 yr. The cliffs were significantly younger than the inner treads, which tended to be younger than the outer treads. Radiocarbon dates from the regolith of 3854 to 4821 cal yr BP (2s range) indicated maximum rates of cliff recession of »0.1 mm/yr, which suggests the onset of terrace formation before the last glacial maximum. Age, angularity, and size of clasts, together with planation across bedrock structures and the seepage of groundwater from the cliff foot, all support a process-based conceptual model of cryoplanation terrace development in which frost weathering leads to parallel cliff recession and, hence, terrace extension. The availability of groundwater during autumn freezeback is viewed as critical for frost wedging and/or the growth of segregation ice during prolonged winter frost penetration. Permafrost promotes cryoplanation by providing an impermeable frost table beneath the active layer, focusing groundwater flow, and supplying water for sediment transport by solifluction across the tread. Snow beds are considered an effect rather than a cause of cryoplanation terraces, and cryoplanation is seen as distinct from nivation.

DOI: 10.1017/qua.2019.41

2021028812 Huang Changfu (University of Science and Technology Beijing, School of Civil and Resources Engineering, Beijing, China); Li Qun; Wu Shunchuan and Liu Yang. Subgrade stability evaluation in permafrost regions based on unascertained measurement model: Geotechnical and Geological Engineering, 37(2), p. 707-719, 31 ref., April 2019.

DOI: 10.1007/s10706-018-0642-4

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2021030582 Batchelor, Cameron J. (University of Wisconsin at Madison, Department of Geoscience, Madison, WI); Orland, Ian J. and Marcott, Shaun. Late Pleistocene permafrost conditions along the southern margin of the Laurentide ice sheet [abstr.]: in Geological Society of America, 2020 annual meeting; GSA 2020 connects online, Abstracts with Programs - Geological Society of America, 52(6), Abstract no. 250-3, October 2020. Meeting: Geological Society of America, 2020 annual meeting; GSA 2020 connects online, Oct. 26-30, 2020, World Wide Web.

Permafrost covered extensive areas of North America during past glacial periods of the late Pleistocene, yet determining the precise timing of permafrost emplacement beyond the Last Glacial Maximum (LGM) has proved challenging. This has primarily stemmed from the limitation of the geochronological methods traditionally used to date geomorphic relicts of permafrost as well as the preservation quality of those relicts beyond the LGM. Speleothems (cave carbonates), in combination with the U-series geochronometer, have provided precisely dated records of past climate change and have also proven useful for determining past permafrost conditions at high-latitudes and -altitudes because their growth requires liquid water. Here we present a new record of speleothem growth from Cave of the Mounds in southwest Wisconsin based on 141 U-series ages that span the last 250 ka (Batchelor et al., 2019, Geophysical Research Letters). This record demonstrates that local permafrost conditions were sustained during MIS 2 but intermittent across MIS 6. During MIS 2, subzero annually-averaged air temperatures persisted in southwest Wisconsin forming perennially frozen ground from 33-14 ka that inhibited speleothem growth. In contrast, we find recurring speleothem growth throughout MIS 6, including the coldest interval of the glacial phase. A compilation of published speleothem U-series records across central North America indicates that this pattern persists regionally. Furthermore, this result is consistent with a network of sea surface temperature reconstructions from mid- and tropical latitudes that suggest global temperatures were approximately 0.6 ± 0.4 °C warmer during MIS 6 than MIS 2.

DOI: 10.1130/abs/2020AM-356394

2021030514 Cohen, Denis (New Mexico Institute of Mining and Technology, Hydrology Program, Socorro, NM); Person, Mark and Fischer, Urs. Glaciations, permafrost, and paleo groundwater flow in Switzerland [abstr.]: in Geological Society of America, 2020 annual meeting; GSA 2020 connects online, Abstracts with Programs - Geological Society of America, 52(6), Abstract no. 190-6, October 2020. Meeting: Geological Society of America, 2020 annual meeting; GSA 2020 connects online, Oct. 26-30, 2020, World Wide Web.

We developed a hydrogeologic model using Elmer/Ice to study the impacts of permafrost development and glaciations on regional groundwater flow patterns across Switzerland over the past 100,000 years. Elmer/Ice is a high-performance computer code that solves for coupled variable-density groundwater flow, heat transfer (including permafrost formation/melting), and geomechanical loading. Permeability reduction in the model occurs as a function of pore fluid ice content. The model included 12 hydrostratigraphic units as well as a thick portion of the underlying crystalline basement. The cross-sectional model was oriented NW-SE from the Alps into the foreland region of Switzerland and was 132 km in length and over 15 km thick. We used sine function boundary conditions to represent temporal changes in ice sheet thickness and land surface temperatures along the top boundary. Model results indicate that following the glacial maximum, permafrost formation occurred within the Alps which partially blocked upland recharge. At the glacial maximum, the thick alpine ice sheet maintains wet-based conditions enhancing recharge. Enhanced hydraulic gradients during periods of glaciation resulted in temperature overturns due to convective heat transfer effects both in upland and lowland regions. The overturns in the lowland profiles are not observed in lowland today due to lower groundwater flow rates and vertical conductive thermal relaxation. The model results should be viewed as conceptual since we imposed idealized boundary conditions.

DOI: 10.1130/abs/2020AM-351618

2021030583 Del Vecchio, Joanmarie (Pennsylvania State University, Department of Geosciences, University Park, PA); Ivory, Sarah J.; Leddy, Matthew; Mount, Gregory J. and DiBiase, Roman A. Erosional and ecological response to climate change in a periglacial landscape 14-8 ka, Central Appalachia [abstr.]: in Geological Society of America, 2020 annual meeting; GSA 2020 connects online, Abstracts with Programs - Geological Society of America, 52(6), Abstract no. 250-4, October 2020. Meeting: Geological Society of America, 2020 annual meeting; GSA 2020 connects online, Oct. 26-30, 2020, World Wide Web.

Thawing permafrost landscapes are important exporters of carbon and sediment. Warming impacts hydrology and surface processes but also ecology through changes in dominant vegetation. Ecology, in turn, affects a landscape's sediment, water and carbon budget. This has implications for the rapidly changing modern Arctic, yet feedbacks between erosion, vegetation and carbon export under warming remain unclear. Analog sites from ancient permafrost landscapes south of the extent of the Laurentide ice sheet show large-scale vegetation change during deglaciation, but comparatively little work has been done on the sedimentary records of these sites, particularly their depositional process, rate, and timing. Here we target sediments preserved in a central Appalachian peat bog to understand sedimentation of a permafrost landscape across the last deglacial warming. We use ground-penetrating radar, radiocarbon and geochemistry to quantify sedimentation volume, style, and provenance, and correlate depositional changes to global climate and local vegetation change. We show how bulk geochemistry in sediments track the relative contribution of dust versus locally derived sediment. Solifluction, which deposited coarse debris on basin margins, was active as late as ~14 ka; however, in the bog center, both peat and clastic sedimentation rates, controlled mostly by dust, were low through the warming associated with the Bolling-Allerod (BA) ~15-13 ka. This sedimentation history, paired with the expansion of grasses in the basin during the BA, leads us to conclude the area remained dry despite warming through the Younger Dryas (YD). In contrast, between ~10-9 ka, water level rose rapidly, concurrent with deposition of fines on basin margins, which we interpret as effects of increased rainfall and slopewash. Post-YD sediment geochemically resembles dust more than BA sediments despite negligible dust flux in the early Holocene, implying a flushing of dust stored on hillslopes that had not occurred during the drier BA. Thus, we interpret that during late glacial warming, hillslope processes were driven predominantly by temperature changes rather than moisture. In contrast, during early Holocene warming, increased rainfall enhanced erosion via fluvial processes and instigated vegetation turnover in response to erosion.

DOI: 10.1130/abs/2020AM-357460

2021030581 Merritts, Dorothy J. (Franklin and Marshall College, Department of Earth and Environment, Lancaster, PA); Walter, Robert C.; Ruck, John; Hertzler, Nicholas; Barter, Rebecca and Jean, Jevelson. Mapping the last permafrost maximum boundary south of the last glacial maximum ice margin, Eastern U.S. Appalachian region [abstr.]: in Geological Society of America, 2020 annual meeting; GSA 2020 connects online, Abstracts with Programs - Geological Society of America, 52(6), Abstract no. 250-2, October 2020. Meeting: Geological Society of America, 2020 annual meeting; GSA 2020 connects online, Oct. 26-30, 2020, World Wide Web.

Relict landforms and sediments beyond the Last Glacial Maximum (LGM) ice margin are used to deduce paleoclimatic conditions and geomorphic processes that produced and transported frost-weathered sediment. We focus on landforms diagnostic of continuous permafrost to reconstruct the maximum permafrost extent, the Last Permafrost Maximum (LPM), south of the LGM ice margin in the Eastern U.S. Appalachian region. Ground cracking (aka "frost cracking") during cold conditions associated with modern continuous permafrost (<-6°C MAAT) commonly produces thermal contraction polygons (TCPs) along the boundaries of which ice or sand wedges develop. We mapped thousands of TCPs in shale bedrock throughout Pennsylvania and Maryland, from the LGM ice margin southward ~400 km. Others have mapped TCPs in coastal plain sediments to the east over a similar latitudinal distance. Using lidar digital elevation data and field work, we map another ubiquitous landform associated with frost weathering and periglacial conditions, relict lobes of bouldery colluvium up to several m in height and 10s of m in width, along sandstone ridges adjacent to shale hills within the same ~400 km zone. Lobe frequencies decrease from >18 to ~9 lobes/km2 over a distance of 250 km from the LGM ice margin, diminish markedly to ~3 lobes/km² at 300 km, and disappear completely south of ~ 400 km. We note that periglacial conditions suitable for formation of TCPs also produced the sand-boulder colluvium that mantles hillslopes in this region, and further propose that these features are diagnostic of continuous permafrost in this setting. Detailed stratigraphic and sedimentologic work at several relict lobes exposed in large, new roadcuts near the LGM ice margin in Pennsylvania further supports our hypothesis that large lobe formation occurs in association with permafrost, in particular thawing of the active layer that results in intermittent downslope motion of an ~1-2 m thick layer of frost-weathered sediment. Previously, we used OSL to determine that the sandy infill of one TCP was deposited about the time of the LPM, and we are completing cosmogenic isotope analysis of sediment within a relict lobe near the LGM ice margin. From regional mapping and field work at individual outcrops, we conclude that TCPs and lobes are cogenetic and diagnostic of continuous permafrost.

DOI: 10.1130/abs/2020AM-358914

2021030489 Piliouras, Anastasia (Los Alamos National Laboratory, Earth and Environmental Sciences Division, Los Alamos, NM); Lauzon, Rebecca and Rowland, Joel C. Effects of ice and permafrost on delta depositional processes; implications for a warming Arctic [abstr.]: in Geological Society of America, 2020 annual meeting; GSA 2020 connects online, Abstracts with Programs - Geological Society of America, 52(6), Abstract no. 187-3, October 2020. Meeting: Geological Society of America, 2020 annual meeting; GSA 2020 connects online, Oct. 26-30, 2020, World Wide Web.

River deltas create sedimentological records that help us interpret rates and mechanisms of sediment transport and local environmental conditions of the past. In the Arctic, ice and permafrost play a large role in governing depositional processes, but their influence is expected to decrease with warming temperatures. Here, we present results from numerical modeling of Arctic deltas aimed at understanding how ice and permafrost influence river delta dynamics and depositional patterns. Both ice and permafrost limit channel mobility, enhance overbank deposition, and roughen shorelines. Thick ice increases offshore channel incision and sediment delivery, resulting in an offshore-extending channel network and the creation of a subaqueous ramp nearshore. Permafrost stabilizes channels and focuses deposition near the channels, leading to enhanced channel levee development. Levee growth is further enhanced by overbank flooding due to ice-driven changes in water surface elevations. Overbank flooding leads to more extensive levees on deltas with both ice and permafrost compared to deltas with only permafrost. This limits channel infilling, helping to preserve abandoned channels on the delta plain. Ice can block smaller channels for much of the year, such that small channels are less geomorphically active than larger channels. Very resistant permafrost may damp this effect, as permafrost inhibits channel avulsion, resulting in fewer active channels on the delta plain that are capable of conveying river discharge to the coastal ocean. These results suggest that the loss of both ice and permafrost in a warming climate will increase lateral channel mobility, decrease the frequency of overbank flooding and therefore rates of delta plain aggradation, limit levee deposition, increase shoreline progradation rates, and decrease offshore transport of sediment.

DOI: 10.1130/abs/2020AM-351134

2021032289 Efremov, V. N. (Russian Academy of Sciences, Siberian Branch, Melnikov Permafrost Institute, Laboratory of Permafrost Engineering, Yakutsk, Russian Federation). Modeling frequency dependences of surface impedance on geoelectrical structure of frozen ground in range 1-10⁸ Hz: in International science and technology conference "EarthScience", IOP Conference Series. Earth and Environmental Science, 459(5), Article 052085, illus., 20 ref., April 2020. Meeting: International science and technology conference "EarthScience", Dec. 10-12, 2019, Russky Island, Russian Federation.

The results of numerical modeling of frequency dependence of permafrost surface impedance in a band of 1 Hz to 100 MHz are shown for typical geoelectric sections (GESs) of Central Yakutia. Particular qualities of frequency dependence are represented by oscillation values in a wide frequency band. The role the displacement and conduction currents in permafrost for the given range of frequencies play is marked. Two main bilayer models of permafrost are discussed: weak-inductive and strong-inductive models. Additional three-six layer models are considered along with indication of their particular qualities and conformity with natural sections. The influence of effect of thin conductive layer in permafrost is shown by sites long half-period occurrence of oscillation of impedance' module and argument values, caused by displacement currents predominance in the horizon of frozen mellow sediments and by conduction currents outweighing in the underlying horizon. One marks the significance the phase curves when used for determination of GES type under condition of approximate automatic interpretation of radio impedance and RMT methods data. Copyright Published under licence by IOP Publishing Ltd.

DOI: 10.1088/1755-1315/459/5/052085

2021032270 Erofeevskya, L. A. (Russian Academy of Sciences, Siberian Branch, Institute of Oil and Gas Problems, Laboratory of Caustobioliths Geochemistry, Yakutsk, Russian Federation) and Aleksandrov, A. R. Liquidation of oil and petroleum products spills based on use of Na and Ca-differences of zeolite: in International science and technology conference "EarthScience", IOP Conference Series. Earth and Environmental Science, 459(5), Article 052011, illus. incl. 2 tables, 23 ref., April 2020. Meeting: International science and technology conference "EarthScience", Dec. 10-12, 2019, Russky Island, Russian Federation.

The article discusses the use of ecologically and economically practical proved methods of neutralizing the soil ecosystems in Yakutia after emergency oil spills. Experimental studies have been made to develop a new biosorbent based on a natural sorbent. The natural zeolite Na and CA-differences from the Khonguruu deposit (The Republic of Sakha (Yakutia), Russia) is used as a base for obtaining the biosorbent. The necessary typification of zeolite deposits revealed at the stage of exploration, in order to determine the field of practical application of raw materials in the preparation of the field for industrial development. The types of raw materials according to the cationic composition difference are identified: clinoptilolite-heulandite and heulandite. A brief description of the material composition and averaged physico-chemical characteristics of various types of zeolite raw material is given. We present the results of the experimental application of hydrocarbon oxidizing microorganisms (HOM) immobilized on zeolite (clinoptilolite-heulandite series) from the Khonguruu deposit in oil-contaminated soils. It has been established that the obtained biomineral compositions provide a significant activation of petroleum hydrocarbons (HC) biodegradation in the soil. In general, the technology of using zeolite raw materials for cleaning up oil spills from different types of permafrost soils provides a significant ecological and economic effect, thus contributing to the reduction of the time for rehabilitation of disturbed lands and the improvement of the environment in the disturbed territory. Copyright Published under licence by IOP Publishing Ltd.

DOI: 10.1088/1755-1315/459/5/052011

2021032269 Glyaznetsova, Yu. S. (Russian Academy of Sciences, Siberian Branch, Institute of Oil and Gas Problems, Laboratory of Caustobioliths Geochemistry, Yakutsk, Russian Federation); Zueva, I. N. and Chalaya, O. N. Experience in the remediation of oil polluted soils of the Arctic zone of Yakutia: in International science and technology conference "EarthScience", IOP Conference Series. Earth and Environmental Science, 459(5), Article 052010, illus. incl. 1 table, 24 ref., April 2020. Meeting: International science and technology conference "EarthScience", Dec. 10-12, 2019, Russky Island, Russian Federation.

In the Arctic zone of Yakutia, geochemical studies have been carried out to study the state of the soil in one of the tank farms. The row of informative analytical indicators was used to characterize the composition of oil pollution and assess the features of its biodegradation processes in permafrost soils. The features of the chemical composition of oil pollution in soil samples with a long-term contamination are revealed and are taken into account at developing methods for cleaning soils from "old" oil pollution. An experiment on the biological treatment of soils with a biological product based on indigenous hydrocarbon-oxidizing microorganisms isolated from permafrost soils was conducted. The initial oil content was 34594 mg kg^-1. After 3 months of incubation of a biological product, along with a decrease in the residual oil content, the composition of pollution changed in the direction of increasing the content of resin-asphaltene components and decreasing - hydrocarbons. The proportion of oxygen-containing groups and bonds has significantly increased in the chemical structure of alcohol-benzene resin. In the composition of alkane hydrocarbons, a redistribution is established both within the homologous series and between different rows of homologues. The degree of destruction of oil pollution reached 56.6%. Copyright Published under licence by IOP Publishing Ltd.

DOI: 10.1088/1755-1315/459/5/052010

2021032267 Lifshits, S. Kh. (Russian Academy of Sciences, Siberian Branch, Laboratory of Caustobioliths Geochemistry, Yakutsk, Russian Federation); Glyaznetsova, Yu. S. and Popova, N. I. Features of transformation of oil-contaminated soils in Arctic region: in International science and technology conference "EarthScience", IOP Conference Series. Earth and Environmental Science, 459(5), Article 052007, illus. incl. 1 table, 26 ref., April 2020. Meeting: International science and technology conference "EarthScience", Dec. 10-12, 2019, Russky Island, Russian Federation.

A study of the comparative characteristic of Yakutia's frozen soils ability to remediation, when contaminated with oil, has been carried out. The samples of permafrost soils from the territories of the the Republic of Sakha (Yakutia), exposed to industrial pollution by oil and its products, with old periods of pollution (10 divided by 12 years) were examined. Remediation was not carried out anywhere. In the soils of the western part of Yakutia, despite a high residual level of pollution (8.58%), signs of oxidative destruction of petroleum hydrocarbons are clearly visible (high content of resinous components (61.3%)), and almost complete transformation of acyclic hydrocarbons. In arctic soils, self-remediation processes occur at a significantly slower pace. In these soils the content of hydrocarbon fractions is still high (60.3-64.9%). There is no selectivity in the transformation processes of individual acyclic hydrocarbons. This suggests that the oxidative destruction of oil pollution in Arctic soils is mainly influenced by physical and chemical environmental factors, rather than microbiological oxidation. The low microbiological activity of hydrocarbon-oxidizing microorganisms in the Arctic soils indicates the need to develop special remediation measures to clean the soil from oil pollution. Copyright Published under licence by IOP Publishing Ltd.

DOI: 10.1088/1755-1315/459/5/052007

2021032266 Makarov, V. N. (Russian Academy of Sciences, Siberian Branch, P. I. Melnikov Institute of Permafrost, Geochemistry Laboratory, Yakutsk, Russian Federation); Nogovitsyn, D. D. and Sheina, Z. M. Hydrology and ion sink of the Arctic River Alazeya: in International science and technology conference "EarthScience", IOP Conference Series. Earth and Environmental Science, 459(5), Article 052006, illus. incl. 2 tables, 19 ref., April 2020. Meeting: International science and technology conference "EarthScience", Dec. 10-12, 2019, Russky Island, Russian Federation.

The features of hydrology and flow of dissolved substances of the Alazeya River located above the Arctic Circle in the area of continuous distribution of permafrost are considered. As starting materials the results of field studies and laboratory analyses of water samples made by the complex research expedition were used. The Alazeya River in hydrological and hydrochemical relation is a little-studied river of the Arctic zone. The river basin is characterized by minimal human pressure. The territory of the Alazeya basin is one of the hard-to-reach Arctic regions of the North-East Yakutia with natural complexes. Precipitation, groundwater and underground ice of active layer and permafrost are the primary power supply of surface waters. Annually 0.5 million tons of dissolved substances are removed by the processes of fluvial denudation from the Alazeya basin to the East Siberian Sea. Module of the ion sink is very low - 6.8 tons/km². It is typical for the sluggish rivers of the Arctic regions. Minimum value is a result of the Arctic climatic and landscape parameters affecting the intensity of chemical weathering of rocks. The ion sink of the Alazeya River is almost independent from human influence and determined by the geochemical properties of elements, lithological features of rocks and soil composition of the river basin, climatic conditions, and vegetation. Copyright Published under licence by IOP Publishing Ltd.

DOI: 10.1088/1755-1315/459/5/052006

2021032262 Shestakova, A. A. (Russian Academy of Sciences, Siberian Branch, Melnikov Permafrost Institute, Geomatics Group, Yakutsk, Russian Federation); Spektor, V. B. and Torgovkin, Ya I. Approaches to engineering geocryological zonation of the Republic of Sakha (Yakutia): in International science and technology conference "EarthScience", IOP Conference Series. Earth and Environmental Science, 459(5), Article 052001, illus. incl. 7 tables, 20 ref., April 2020. Meeting: International science and technology conference "EarthScience", Dec. 10-12, 2019, Russky Island, Russian Federation.

This paper describes the engineering geocryological zoning of the Republic of Sakha (Yakutia) which was performed based on analysis of the main controlling factors and their cartographic generalization. Several schematic maps were compiled depicting topography (landforms), geocryological processes, soils and rocks, permafrost conditions and seismicity. The types of engineering geocryological conditions were assessed and scored to classify areas by suitability for engineering. The paper begins with a brief Introduction which clarifies the objectives and importance of the research. The Methods section describes the ranking of control factors adopted for the convenience of zonation. The next section discusses the factors controlling engineering geocryological conditions in Sakha (Yakutia). The Results and Discussion section describes the series of maps produced comprising: a map of morphostructural zonation, a zonation map of geocryological processes intensity, a zonation map of ground and permafrost conditions, a map of seismic zonation. It also presents an integrated analysis of the controlling factors and concludes that the Coastal Lowlands and Shallow Seashelf Region is most challenging for engineering. For further refinement of engineering conditions, it seems advisable to prepare permafrost-landscape, geomorphological and other regional maps that would be useful for assessing economic feasibility of projected developments in the Republic of Sakha (Yakutia). Copyright Published under licence by IOP Publishing Ltd

DOI: 10.1088/1755-1315/459/5/052001

2021028410 Wang Xiqiang (Chinese Academy of Sciences, Qilian Alpine Ecology and Hydrology Research Station, Lanzhou, China); Chen Rensheng; Han Chuntan; Yang Yong; Liu Junfeng; Liu Zhangwen and Song Yaoxuan. Changes in river discharge in typical mountain permafrost catchments, northwestern China: in The third ASQUA conference; (Part II), Quaternary environments and ancient civilizations in east Asia (Yi, Sangheon, editor; et al.), Quaternary International, 519, p. 32-41, illus. incl. 5 tables, sketch map, 56 ref., June 10, 2019. Meeting: The 3rd ASQUA conference, Sept. 4-8, 2017, Jeju, South Korea.

River discharge has changed significantly in high-latitude permafrost regions due to climate warming, but these changes are still unclear in high-mountain permafrost regions. Long-term discharge data of 8 inland river catchments in the Qilian Mountains were analysed, and increased winter (minimum monthly) discharge, decreased recession coefficient and decreased ratio of maximum monthly to minimum monthly discharge (Q_max/Q_min) was detected commonly. This implies that the degradation of mountain permafrost under the warming climate has significantly changed the river discharge of high mountain catchments. Permafrost degradation may influence the relationship between summer precipitation and the following cold-season discharge by promoting liquid water infiltration, increasing the groundwater storage capacity and supporting deep flow paths. However, the role of summer precipitation on cold-season discharge may be affected by different glacier runoff rates (the percentage of glacier runoff contribution to the total annual flow). Under permafrost degradation, summer precipitation will strongly influence the following cold-season discharge in catchments with a low glacier runoff rate (less than 10%) but not the discharge in catchments with a high glacier runoff rate (more than 40%). The results of this study may provide important information for local water resource management and future permafrost hydrological simulation.

DOI: 10.1016/j.quaint.2018.11.010

2021028693 Berry, Bay (Dalhousie University, Department of Earth Sciences, Halifax, NS, Canada); Whalen, Dustin and Lim, Michael. Permafrost coast sensitivity to air temperature and storm influence on Pullen Island, Northwest Territories, Canada [abstr.]: in Atlantic universities geoscience conference 2019; abstracts, Atlantic Geology, 55, p. 380, 2019. Meeting: 69th annual Atlantic universities geoscience conference, Oct. 24-26, 2019, Antigonish, NS, Canada.

DOI: 10.4138/atlgeol.2019.013

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