Thermal Denudation Research Articles

Factors of thermal denudation activation and thermicirques activity on central Yamal in 2010–2018

Factors of thermal denudation activation and thermicirques activity on central Yamal in 2010–2018

Characterizing Batagay megaslump topography dynamics and matter fluxes at high spatial resolution using a multidisciplinary approach of permafrost field observations, remote sensing and 3D geological modeling

Retrogressive thaw slumps (RTS) are an important landform of rapid permafrost degradation in regions with very high ground ice contents. RTS mobilize significant amounts of sediment, meltwater and organic carbon and impact downstream hydrological systems by directly affecting topography and water quality. The term megaslump has previously been coined for RTS exceeding 20 ha in size. The Batagay megaslump in the Yana highlands of NE Siberia with an area of 87.6 ha (in 2023, including the bowl-shaped part and the erosional outlet) has been identified as the largest megaslump on Earth. We use very high resolution remote sensing from satellite data and drones, geological structure modeling, and field data to assess how much and what material is thawed and mobilized in the Batagay megaslump. The total volume of permafrost thaw and material loss from the Batagay RTS amounts to about 1 million m3 per year. The material is by one third composed of thawed sediments and by two thirds of melted ground ice. About 4000 to 5000 tons of previously permafrost-locked organic carbon is released every year. Organic carbon content has been measured as Total Organic Carbon (TOC) of sediments and as Dissolved Organic Carbon (DOC) of ground ice. From its formation in the 1970s until 2023, the Batagay RTS – due to thermal denudation and headwalls retreat – mobilized a total volume of about 34.7 million m3 of which 23.4 million m3 were melted ground ice and 11.3 million m3 were thawed deposits including a total of about 169,500 t organic carbon. With these rates of sediment and carbon mobilization, the Batagay megaslump is not only a prominent local feature of rapid permafrost thaw, but offers excellent conditions to study rates and mechanisms of rapid permafrost degradations and to calculate the stock and release of, e.g., organic matter.

Запасы углерода верхних отложений почв островов Самойловский, Большой Ляховский и Котельный

In the tundra swamps of Samoilovsky Island carbon reserves amounted to 21.5 kg TOC/m2 and 0.6 kg TIC/m2. On Bolshoy Lyakhovsky Island it makes 51.6 kg TOC/m2 and 5.9 kg TIC/m2. In the grass-hypnum bogs of Kotelny island 12.4 kg TOC/m2 and 0.3 kg TIC/m2 are deposited. On the coastal outcrops of Samoilovsky island with thermal abrasion and thermal denudation reserves vary between 85.8—115.5 kg TOC/m2 and 6.9—7.3 kg TIC/m2, and on Bolshoy Lyakhovsky island — 51.6 kg TOC/m2 and 5.4 kg TIC/m2. In the baidzharakhs of Bolshoy Lyakhovsky island the average carbon reserves make 38.6 kg TOC/m2 and 6.1 kg TIC/m2.

Morphodynamic Types of the Laptev Sea Coast: A Review

The Laptev Sea coast has a unique high-latitude and dynamic landscape. The presence of low-temperature permafrost (below −7 °C) and its high ice content (up to 90%) determine a wide array of permafrost landforms and features. Under the actions of thermal abrasion and thermal denudation, high rates of coastal retreat are evident within this region. Local differences in the geological structure and sea hydrodynamic conditions determine the diversity of this sea coast’s types. In this review, we present the results of a morphodynamic classification and segmentation of the Laptev Sea coast. The integrated approach used in the classification took into account the leading relief-forming processes that act upon this coastal zone. The research scale of 1:100,000 made it possible to identify and characterize the morphologies of the coast and their spatial distributions within the study area. The presented original classification can be considered to be universal for the eastern Arctic seas of Eurasia; it may be used as a basis for further scientific and applied research.

TYPOLOGY OF TERRITORIAL VEGETATION UNITS ON THE EXAMPLE OF THERMOKARST MASSIFS ON KOTELNY ISLAND (NEW SIBERIAN ISLANDS)

In the Arctic, permafrost and underground ice melting is one of the modern problems that requires constant monitoring. In the areas with spreading thick ice-wedge polygonal networks, the territories occupied by groups of mounds separated by trenches formed in the place of melted ice veins are a widespread result of thermokarst. The vegetation of such territories (referred to as massifs) is represented by territorial units of the first hierarchy levels with an intra- (mosaic of patches within communities) and supraphytocoenotic (micro- and mesokombinations: complexes, their aggregates and series) heterogeneity. The shape, size and vegetation of the mounds and trenches change under the influence of thermal denudation, and the vegetation of a whole massif also changes, so it can serve as an indicator of thermokarst intensity. The relief formed by thermokarst is typical of the landscapes of New Siberian Islands. According to the descriptions of 38 massifs made on Kotelny Island in 1974–1975, they were for the first time typified as territorial units of vegetation. In total, 7 types of massifs belonging to 2 classes are identified and characterized: baidzharakh massifs proper (with mineral mounds) and massifs with peat mounds (including 1 type of massifs). The first class comprises 2 groups of types: weakly differentiated massifs (microcombinations) and differentiated massifs (mesocombinations). In the first group, there are 2 types of massifs, in the second one – 4 types. Six distinguished types of baidzharakh massifs correspond to successive stages of massif transformation (a scheme is given). The heterogeneity of massif vegetation becomes more complicated with time, and becomes simpler again, when the massif is destroyed. Embryonal massifs are represented by microcombinations, a group of developed (differentiated) massifs – by mesocombinations, collapsing massifs – by microcombinations. The developed typology of the baidzharakh massifs as territorial vegetation units is convenient for practical work and using in monitoring and comparative assessment of thermokarst intensity in the Arctic areas with different flora and vegetation.

Landforms and degradation pattern of the Batagay thaw slump, Northeastern Siberia

Thaw slumps are clear indicators of rapid permafrost degradation. They form preferentially in near-surface ice-rich permafrost of northern high latitudes after initial thermal disturbance by the subsequent interplay of thermal (thawing of frozen deposits and melting of ice) and mechanical (slumping and erosion) processes. The largest known thaw slump on Earth – the Batagay megaslump – has been identified in sloping terrain on the Yana Upland in northern Yakutia. Its initiation began in the 1980s, with a current area of >0.8 km2. It continues to grow and has headwall retreat rates of up to 15 m per year. While various satellite remote sensing studies of the Batagay thaw slump have been undertaken, on-site studies characterizing internal landforms, terrain changes, and geomorphic processes have not yet been conducted. To fill this knowledge gap and to enhance our understanding of the dynamics of very large thaw slumps, our study employs on-site observations and detailed permafrost sampling combined with unoccupied aerial vehicle data from 2019. The latter were used to generate an orthomosaic, a digital surface model, hypsometric slope profiles and a map of relief types in the thaw slump. Within the Batagay thaw slump, the dynamic relationship between headwall morphology and slump floor is largely determined by the cryolithological structure of the permafrost horizons exposed across the headwall rising up to 55 m above the slump floor. Factors include the thickness and overall high volumetric ground-ice content (up to 87 %) of the cryostratigraphic horizons. Furthermore, the diurnal and seasonal insolation exposure of the headwall perimeter superimposes both thermal denudation activity and meltwater transport of eroded material. Thus, recent degradation patterns are linked to permafrost properties. Therefore, the Batagay thaw slump is not only a window into Earth's past as it reveals ancient permafrost, but its modern dynamics highlight that ongoing rapid permafrost thaw under present Arctic warming is directly influenced by its Quaternary geological and permafrost history.

Fluvio‐thermal erosion and thermal denudation in the yedoma region of northern Alaska: Revisiting the Itkillik River exposure

AbstractRiverbank erosion in yedoma regions strongly affects landscape evolution, biogeochemical cycling, sediment transport, and organic and nutrient fluxes to the Arctic Ocean. Since 2006, we have studied the 35‐m‐high Itkillik River yedoma bluff in northern Alaska, whose retreat rate during 1995–2010 was up to 19 m/yr, which is among the highest rates worldwide. This study extends our previous observations of bluff evolution and shows that average bluff‐top retreat rates decreased from 8.7–10.0 m/yr during 2011–2014 to 4.5–5.8 m/yr during 2015–2019, and bluff‐base retreat rates for the same time period decreased from 4.7–7.5 m/yr to 1.3–1.7 m/yr, correspondingly. Bluff evolution initially involves rapid fluvio‐thermal erosion at the base and block collapse, following by slowdown in river erosion and continuing thermal denudation of the retreating headwall with formation of baydzherakhs. Eventually, input of sediment and water from the headwall diminishes, vegetation develops, and slope gradually stabilizes. The step change in the fluvial–geomorphic system has resulted in a 60% decline in the volumetric mobilization of sediment and organic carbon between 2011 and 2019. Our findings stress the importance of sustained observations at key permafrost region study sites to elucidate critical information related to past and potential landscape evolution in the Arctic.

The Role of Thermal Denudation in Erosion of Ice-Rich Permafrost Coasts in an Enclosed Bay (Gulf of Kruzenstern, Western Yamal, Russia)

Coastal erosion in the Arctic has numerous internal and external environmental drivers. Internal drivers include sediment composition, permafrost properties and exposure which contribute to its spatial variability, while changing hydrometeorological conditions act as external drivers and determine the temporal evolution of shoreline retreat. To reveal the relative role of these factors, we investigated patterns of coastal dynamics in an enclosed bay in the southwestern Kara Sea, Russia, namely the Gulf of Kruzenstern, which is protected from open-sea waves by the Sharapovy Koshki Islands. Using multitemporal satellite imagery, we calculated decadal-scale retreat rates for erosional segments of the coastal plain from 1964 to 2019. In the field, we studied and described Quaternary sediments and massive ground-ice beds outcropping in the coastal bluffs. Using data from regional hydrometeorological stations and climate reanalysis (ERA), we estimated changes in the air thawing index, sea ice-free period duration, wind-wave energy and total hydrometeorological stress for the Gulf of Kruzenstern, and compared it to Kharasavey and Marre-Sale open-sea segments north and south of the gulf to understand how the hydrometeorological forcing changes in an enclosed bay. The calculated average shoreline retreat rates along the Gulf in 1964–2010 were 0.5 ± 0.2 m yr−1; the highest erosion of up to 1.7 ± 0.2 m yr−1 was typical for segments containing outcrops of massive ground-ice beds and facing to the northwest. These retreat rates, driven by intensive thermal denudation, are comparable to long-term rates measured along open-sea sites known from literature. As a result of recent air temperature and sea ice-free period increases, average erosion rates rose to 0.9 ± 0.7 m yr−1 in 2010–2019, with extremes of up to 2.4 ± 0.7 m yr−1. The increased mean decadal-scale erosion rates were also associated with higher spatial variability in erosion patterns. Analysis of the air thawing index, wave energy potential and their total effect showed that inside the Gulf of Kruzenstern, 85% of coastal erosion is attributable to thermal denudation associated with the air thawing index, if we suppose that at open-sea locations, the input of wave energy and air thawing index is equal. Our findings highlight the importance of permafrost degradation and thermal denudation on increases in ice-rich permafrost bluff erosion in the Arctic.

Полевые исследования на территории Булунского района (Республика Саха (Якутия)) в 2021 году

The study of the problem of the initial development and subsequent settlement by ancient human populations of extreme natural zones is difficult to study, but, in the case of discovering archaeological and paleontological locations, it is a very informative source. The first discoveries of traces of the presence of an ancient man in the Bulunsky district date back to the beginning of the 19th century, and they continued sporadically throughout the entire 20th century, and especially intensified at the beginning of the 21st century. The discovered locations are represented by both mass material and single finds. In 2021, field studies were carried out in Neelov Bay on the side of the Bykovsky peninsula and the Kozhevin-Vollosovich interfluve in the north of the Kotelny Island of the Anju archipelago of the New Siberian Islands. These areas represent the arctic tundra with active thermal denudation processes, which contribute to the discovery of paleontological remains of mammoth fauna, and often lead to the regular seasonal destruction of paleontological and archaeological sites. New archaeological and paleontological material found on the southeastern coast of Neelov Bay demonstrates the intensity of the development of the most ancient populations of people in the Arctic zone of Eastern Siberia. The result was the discovery of new Pleistocene fauna complexes, as well as the verification of the previously discovered Taba-Yuryakh location. The obtained osteological material belongs to the Late Pleistocene mammoth complex. On some of the bones, traces of human influence were found, presumably hunting or cutting, which indicates the active development of the ancient population of the Arctic zone of Yakutia in the Paleolithic. The obtained data will make it possible to significantly correct the existing ideas of the chronology and sequence of development of the Paleolithic industries and paleoecological settings of this region at a later stage of the Quaternary age.

Coloured dissolved organic matter in aquatic ecosystems of three representative regions of the Arctic according to the data obtained in year 2019

In this study the laboratory analysis of water samples from three representative regions of the Arctic for content of coloured dissolved organic matter (CDOM) – the important component of natural waters, which has a direct impact on state of aquatic ecosystems, was made. Samples were collected from water objects from the Kola Peninsula, the Yamal Peninsula and the Lena River Delta. The results of the analysis made it possible to determine CDOM concentrations in water. According to the average values, the highest values were obtained for the Yamal Peninsula and lowest – for the Kola Peninsula. The predominance of allochthonous CDOM in the water objects from all three regions was revealed. Moreover, the complete absence of photodegradation processes was determined. For the lakes and rivers from the Kola Peninsula it was also possible to follow seasonal dynamic of CDOM concentration in water and to compare it with earlier obtained data concerning seasonal CDOM dynamic in the Lena River Delta. Results are actual due to the currently existing tendency of climate change which leads to intensification of thermal denudation and thermal erosion processes in the cryolithozone, which are consequently increasing income of allochthonous CDOM in water objects.

Fifty four years of coastal erosion and hydrometeorological parameters in the Varandey region, Barents Sea

The southeast coastline of the Barents Sea in the area of the Varandey settlement is characterized by warm permafrost. Coastal studies conducted since the early 1980s have shown coastal retreat with average erosion rates of up to 2–5 m/yr from 1969 to 1987 at different locations in the area. The present study summarizes long-term (1951–2013) observations of environmental forcing in the area, and estimations of retreat rates based on recent fieldwork (2011–2013) and remote sensing studies (1961–2012). Such data is of primary importance for any infrastructure developments in the study area. The coastline was divided into three conditional geographical sectors: Pesyakov, Varandey, and Medynskiy. It was found that the average erosion rate in eroding parts of Pesyakov sector was 2 m/yr, in the western part of Varandey sector—1.8 m/yr, and in the entire Medynskiy sector—2.3 m/yr over the last 54 years. Remote sensing observations documented the destruction of numerous buildings in the coastal zone of the Novyy Varandey settlement in 2004–2012. A striking coastal bluff recession of 19.6 m/yr over the 15-km-long coastline in Medynskiy was observed between 2010 and 2011, following a storm surge in the area in the summer of 2010. Fluctuations of environmental forcing (air temperatures, wave energy factor, significant wave height, and sea level) were observed in the Varandey area in 1979–2013. The long-term evolution of environmental forcing exhibits an increasing trend. The increase (0.6–4.8 m/yr) of average long-term erosion rates in the Medynskiy sector from 1961 to 2013 followed the evolution of environmental forcing in 1979–2013. Different coastal erosion responses and processes varying from a stable situation to active erosion due to mechanical wave action, thermal abrasion, thermal denudation, or a combination of these processes were identified in the Varandey area.

Satellite images in the new Atlas «Russian Arctic»

The increasing interest in the Arctic promotes appearance of new cartographic products to provide information for the primary tasks of this region development. So, several atlases of the Arctic have been already published. At the initiative and with the financial support from the oil and gas industry, a new Atlas «Russian Arctic» is being prepared for publication, in which considerable attention is given to the environmental aspects of the development of the North with account for conditions of changing climate. Unlike previous atlases, this Atlas contains thematic sets of satellite images reflecting changes in the natural environment, in particular, different types of natural ice under conditions of warming. The space part of the Atlas developed by the authors of this article covers a number of subjects. Thus, the decrease in the area of sea ice is illustrated by the materials of shooting from the space of the Northern polar cap for the period of the largest reduction in the area. Images made in different time fix retreating of the shores, composed of underground ice, being the result of the processes of thermal abrasion, thermal erosion and thermal denudation. Complicated ice conditions of navigation in the Ob Bay and characteristics of the Arctic rivers mouths are presented by pictures of tidal estuaries of the rivers Mezen and Kuloi. Images of ice jams at the mouth of the Northern Dvina River and materials of space monitoring of measures for liquidation of them are also given in the Atlas. Special attention is given to forms of permafrost relief, which are well displayed in high-resolution images. They show a polygonal micro-relief of different types and stages of development of them, as well as frost mounds, dales, and thermo-erosion forms. Formation of aufeises (naleds), thermokarst lakes, and craters of gas outbursts is also shown. The wildlife of the Arctic is represented in the Atlas as well. The pictures present a visual image of different types of tundra. The influence of warming on vegetation development is well reflected in the photo map of the dynamics of the vegetation index for 2000-2009, showing the growth of phytomass in the European North. The Atlas contains unique materials of satellite monitoring of Arctic mammals - walruses and seals. The impact of using mineral resources on the vulnerable nature of the Arctic is shown in the Khibiny region. Prominent examples of the vegetation degradation in the areas of Norilsk and Monchegorsk cities are given, where technogenic wastelands have been formed under the sulfuric acid fumes of the copper-nickel plants.

Activation of Cryogenic Processes in Central Yamal as a Result of Regional and Local Change in Climate and Thermal State of Permafrost

Various climatic parameters (average annual, winter, and summer air temperature, winter and summer total precipitation) and their temporal variability are analyzed to explain the activation of cryogenic processes in Central Yamal. The effect of fluctuations of these parameters on the thaw depth and ground temperature is analyzed. The regression analysis is carried out to reconstruct ground temperature during earlier periods of time in the years preceding the activation of thermal denudation and the formation of gas emission craters.

DYNAMICS OF PERMAFROST IN THE COASTAL ZONE OF EASTERN-ASIAN SECTOR OF THE ARCTIC

The study summarizes results on the cryogenic dynamics in the coastal zone. The paper shows that ongoing climate warming and shrinking of ice extent of the Arctic seas triggers both thermogenic and cryogenic processes at the same time. The first group includes thermal abrasion, thermal denudation, degradation of submarine permafrost, and the second one is the syncriogenesis of the new-formed coastal-marine sediments. The first group results in an increase of the retreat rate of coasts, the second results in the islands formation on banks and shallows where the domination of bottom thermal abrasion and deepening of the sea bottom has been taken place previously. Arguments for stamukhas and cryogenesis role in islands formation are presented.

Patterns and rates of riverbank erosion involving ice-rich permafrost (yedoma) in northern Alaska

Yedoma, a suite of syngenetically frozen silty ice- and organic-rich deposits with large ice wedges that accumulated during the late Pleistocene, is vulnerable to thermal degradation and erosion because of the extremely high ice contents. This degradation can result in significant surface subsidence and retreat of coastal bluffs and riverbanks with large consequences to landscape evolution, infrastructure damage, and water quality. We used remote sensing and field observations to assess patterns and rates of riverbank erosion at a 35-m-high active yedoma bluff along the Itkillik River in northern Alaska. The total volumetric ground-ice content—including wedge, segregated, and pore ice—was estimated to be ~86%. The process of riverbank erosion and stabilization include three main stages typical of the areas with ice-rich permafrost: (1) thermal erosion combined with thermal denudation, (2) thermal denudation, and (3) slope stabilization.Active riverbank erosion at the main study site started in July 1995, when the Itkillik River changed its channel. The total retreat of the riverbank during 1995–2010 within different segments of the bluff varied from 180 to 280m; the average retreat rate for the most actively eroded part of the riverbank was almost 19m/y. From August 2007 to August 2011, the total retreat varied from 10 to almost 100m. The average retreat rate for the whole 680-m-long bluff was 11m/y. For the most actively eroded central part of the bluff (150m long) it was 20m/y, ranging from 16 to 24m/y. More than 180,000m3 of ground ice and organic-rich frozen soil, or almost 70,000metrictons (t) of soil solids including 880t of organic carbon, were transported to the river from the retreating bank annually. This study reports the highest long-term rates of riverbank erosion ever observed in permafrost regions of Eurasia and North America.

Forecast of geoecological changes on the Bovanenkovo Field, Yamal Peninsula

The development of destructive cryogenic and geo� morphological processes and variations in landscape after ice melting due to technogenic action or climatic warming was forecasted on the basis of factual data on the propagation and position of thick bedded ice bod� ies in the permafrost surface on the gas–condensate field in the Yamal Peninsula. The ability to forecast the development of cryogenic geoecological changes in the explored area under inten� sive technogenic load becomes more and more impor� tant under progressive exploration of the oil–gas depos� its located at high altitudes within the permafrost zones. The cryolitic zone is characterized by a lower resistance to external actions, because it is composed of ice, the lowest temperature and thus thermodynamically most unstable mineral of the upper crust of the Earth predis� posed to phase transformations. The Bovanenkovo gas–condensate field is a typo� morphic area of bedded ice, and therefore, the con� clusions made can be representative for most of the north of Western Siberia [2, 3]. The data on the distri� bution limit, occurrence conditions, and depth of thick ice beds [8–11] are of special importance in investigation of activated destructive processes related to the forecasted climate warming. It is clear that the bedded ice degradation will be accompanied by the active development of different cryolitogenic and postcryogenic processes. It is evident that the temper� ature setting in the permafrost roof plays a significant role in the stability of cryogenic conditions and area morphogenesis. However, the occurrence of thick ice beds in the subsurface will manifest itself in the future in any case at any soil temperature: thermokarst sub� sidence due to water accumulation is inevitable in lowlands, while highlands will be subject to thermal denudation in the course of time. The area of bedded ice has not yet been estimated. The development of distant investigation methods is of special importance for exploration of the hardly accessible Arctic Region. To decode the ice beds devoid of obvious landscape geomorphological features (in contrast to injection ice), it is reasonable to apply a computer program, which would be able to take into account and to com� pare tens of indirect landscape geomorphological fea� tures. The indirect features of bedded ice include large thermokarst cirques, deep lakes located at different hypsometric levels of watershed surfaces, occasionally with the bottom below the sea encroachment line, small lakes with active slope processes, deep river meanders, alluvial cone, and earthflows of thermal denudation material. All these features were recorded in the automated program decoding the area and depth of bedded ice occurrence. The bedded ice con� tours identified in the air images were classified by the ice roof occurrence depth in natural conditions: 1–3, 3–5, 5–10, and over 10 m. It is clear that the deeper the ice, the later the thermal denudation reaches the ice body roof.

Contribution of lateral thermoerosion and thermal denudation to coastal retreat of the Yugorskii Peninsula

Contribution of lateral thermoerosion and thermal denudation to coastal retreat of the Yugorskii Peninsula

Thermal denudation of shore cliffs

Thermal denudation of shore cliffs

Thermal abrasion of sea coasts (part I)

Abstract Along arctic coasts consisting of unconsolidated sediments in permafrost, and especially where these sediments are ice‐rich, the thermal energy of the sea water is added to the normal erosive impact of the waves. The resulting process of erosion due to the combined action of the mechanical and thermal energy of the sea is termed thermal abrasion. This study concentrates on almost every aspect of the retreat of coastal cliffs and changes in the sea bed resulting from this process. The author's fieldwork on Muostakh Island near Tiksi forms the core of the study. Attention is focused particularly on the shape and height of the resulting cliffs, coastal retreat rates and subsequent lowering of the sea bed. In addition attempts are made at calculating rates of thermal abrasion based on water temperature and period of wave action, and of thermal denudation of the subaerial cliff based on air temperatures, solar radiation and the ice content of the sediments. The rate of thermal abrasion of ice‐rich coa...