Long-Term Evolution and Monitoring at High Temporal Resolution of a Rapidly Retreating Cliff in a Cold Temperate Climate Affected by Cryogenic Processes, North Shore of the St. Lawrence Gulf, Quebec (Canada)

This article focuses on the quantification of retreat rates, geomorphological processes, and hydroclimatic and environmental drivers responsible for the erosion of an unconsolidated fine-sediment cliff along the north shore of the Gulf of St. Lawrence (Quebec, Canada). Annual monitoring using field markers over a period of twenty years, coupled with photo interpretation and historical archive analysis, indicates an average annual erosion rate of 2.2 m per year between 1948 and 2017. An acceleration in retreat occurred during the last 70 years, leading to a maximum between 1997 and 2017 (3.4 m per year) and 2000–2020 (3.3 m per year). Daily observations based on six monitoring cameras installed along the cliff between 2008 and 2012 allowed the identification of mechanisms and geomorphological processes responsible for cliff retreat. Data analysis reveals seasonal activity peaks during winter and spring, which account for 75% of total erosional events. On an annual basis, cryogenic processes represent 68% of the erosion events observed and subaerial and hydrogeological processes account for 73%. Small-scale processes, such as gelifraction, solifluction, suffosion, debris collapse, and thermoabrasion, as well as mass movement events, such as slides and mudflows, induced rapid cliff retreat. Lithostratigraphy and cliff height exert an important control on erosion rates and retreat modes, which are described by three main drivers (hydrogeologic, cryogenic, and hydrodynamic processes). Critical conditions promoting high erosion rates include the absence of an ice-foot in winter, the absence of snow cover on the cliff face allowing unrestricted solar radiation, the repetition of winter warm spells, snow melting and sediment thawing, and high rainfall conditions (>30 mm or SPI > 2). The relationships between hydroclimatic forcing and retreat rates are difficult to establish without taking into account the quantification of the geomorphological processes involved. The absence of quantitative data on the relative contribution of geomorphological processes can constitute a major obstacle in modeling the retreat of cliffs with regard to climate change.

AT THE DAWN OF THE GEOCRYOLOGICAL STUDY OF THE ARCTIC REGIONS OF YAKUTIA: INMERO EXPEDITION NO. 1 (1952–1953)

Presents a historical analysis of the research activities of the members of the Expedition No. 1, which was organized by the Obruchev Permafrost Institute of the USSR Academy of Sciences (Moscow) in the Arctic regions of Yakutia in 1952– 1953. This expedition turned out to be the first large-scale geocryological initiative implemented in the named region. In this regard, mainly on the basis of the revealed archival materials, including those introduced by the author for the first time into scientific circulation, a characteristic of the personal composition of the research participants is presented. The geography of the work carried out has been established, covering the previously poorly geocryologically studied Yano- Indigirsky interfluve, the coast of the Laptev Sea and the Bolshoi Lyakhovsky Island, the main routes made by scientists are shown. The key directions of scientific search for permafrost scientists have been identified. The significance of the research carried out for the replenishment of knowledge about the permafrost in the Arctic regions of Yakutia and, in general, the development of geocryological science has been determined. In this regard, plots are presented that characterize the specifics of the geocryological surveys, as well as the improvement of the methodological arsenal of permafrost research in the region. At the same time, it was noted that the work of the members of Expedition No. 1 made it possible to determine a number of the most important features of cryogenic processes and the extent of the spread of permafrost in the Arctic Yakutia, to establish the thickness of the permafrost and its temperature parameters at different depths. In addition, it was found that during the survey a number of important practical results were obtained, including the identification of the composition of permafrost and the depth of the seasonally thawed layer, necessary to optimize the process of transport and industrial development of the region.

Антропология холода: естественные низкие температуры в традиционной системе жизнеобеспечения якутов (XIX в. – 30-е гг. ХХ в.)

Goals. The study aims to determine the influence of a complex of cryogenic factors (snow, ice, permafrost, cold in general) on traditional household and sociocultural practices of the Yakuts including benefits that some representatives of this ethnic group have learned to derive from winter climatological conditions. Materials and Methods. The work analyzes archival materials, scientific literature and the author’s field data. The most important elements of the methodological toolkit are sociocultural analysis and basic principles of cryosophy that suggest analysis of the phenomena of the ‘cold world’ in terms of their resource potential. Results. The paper shows positions (impacts) of low temperatures and accompanying phenomena when it comes to choose a place of location for a winter settlement and layout a farmstead (availability of a reservoir that does not freeze over the winter to its bottom, relative remoteness of permafrost soils from the surface, creation of open spaces for a better view, etc.), and the former’s influence on the architecture and functionality of residential and household buildings. The work introduces certain characteristics of deep freeze practices used for storing and cooking food, employment of cryogenic phenomena and processes for sanitary and hygienic purposes. Special insight is made into the significance of ‘cold’ practices in household activities. Specifically, the study shows that in farming and cattle breeding cryogenic phenomena were used for irrigation of agriculturally used areas, livestock feeding and threshing arrangements. Moreover, the specific climatic regime made it possible to apply quite a range of unique approaches to fishing and hunting. However, one of the most important results obtained during this study is the conclusion — confirmed by definite examples — that the Yakuts practiced conscious control over cryogenic processes in household activities. Conclusions. Based on the above, the paper concludes it is largely due to cold that a big complex of elements of the traditional life sustenance system of the Yakuts had emerged — to further essentially shape the latter’s most representative ethnocultural features.

High alpine rock-wall retreat rates over millennia through thermo-cryogenic pre-conditioned rock fall (Mt. Eiger, Switzerland)

<p>Rock fall processes of various size and magnitude control retreat rates of high alpine rock-walls. For millennial time scales, these retreat rates can be quantified in-situ from concentrations of cosmogenic nuclides along bedrock depth profiles (Mair et al., 2019). We measured cosmogenic <sup>36</sup>Cl and <sup>10</sup>Be along several such profiles at Mt Eiger in the Central Swiss Alps to study the local rock-wall retreat on this time scale (Mair et al., 2019; 2020). The resulting spatial pattern shows that rock-wall retreat rates are low (0.5 to 0.6 ± 0.1 mm/yr) in the higher region of the NW rock-wall, in contrast to both the lower part of the NW rock-wall and the SE face, where rates are high (1.7 ± 0.4 to 3.5 ± 1.4 mm/yr). We link these retreat rates to differences in local temperature conditions, because the patterns of faults and fractures and the lithology of the bedrock are similar at all sites, and thermo-cryogenic processes are known to weaken the bedrock through fracturing, thereby preconditioning the occurrence of rock fall (e.g., Draebing and Krautblatter, 2019). However, it is still unclear how effective and at which rate individual thermo-cryogenic processes contribute to the preconditioning through fracturing. Therefore, we investigate several processes and estimate the probability of bedrock fracturing through the employment of a theoretical frost-cracking model, which predicts cracking intensity from ice segregation. The model results infer a low efficiency in the higher region of the NW rock-wall, but a relatively high one in the lower section of the NW wall and on the SE rock face of Mt. Eiger. Although the model is rather generic, the results disclose a significant control of temperature conditions on the erosional processes and rates. Furthermore, temperature conditions for the last millennia have been similar to present day conditions, as our reconstructions disclose, therefore the cosmogenic-nuclide-based long-term differences in rock-wall retreat rates predominantly stem from large contrasts in the microclimate between the NW and SE walls of Mt. Eiger. Accordingly, the site-specific differences in microclimate conditions could explain the lower retreat rates in the upper part of the NW rock-wall and the rapid retreat in the SW face and in the lower part of the NW rock face.</p><p>References</p><p>Draebing, D. and Krautblatter, M.: The Efficacy of Frost Weathering Processes in Alpine Rockwalls, Geophys. Res. Lett., 46, 6516–6524, doi:10.1029/2019GL081981, 2019.</p><p>Mair, D., Lechmann, A., Yesilyurt, S., Tikhomirov, D., Delunel, R., Vockenhuber, C., Akçar, N. and Schlunegger, F.: Fast long-term denudation rate of steep alpine headwalls inferred from cosmogenic 36Cl depth profiles, Sci. Rep., 9, 11023, doi:10.1038/s41598-019-46969-0, 2019.</p><p>Mair, D., Lechmann, A., Delunel, R., Yeşilyurt, S., Tikhomirov, D., Vockenhuber, C., Christl, M., Akçar, N. and Schlunegger, F.: The role of frost cracking in local denudation of steep Alpine rockwalls over millennia (Eiger, Switzerland), Earth Surf. Dyn., 8, 637–659, doi:10.5194/esurf-8-637-2020, 2020.</p>

Calcium-sulfate wedges in the Atacama Desert as indicators for subsurface dynamics

<p>Polygonal patterned grounds are common surface expressions of subsurface dynamics in periglacial and Martian environments. In the Periglacial these structures are typically associated with vertically laminated wedges in the subsurface being the product of cryogenic processes. These landscape features similarly occur in arid to hyperarid environments, such as in the Atacama Desert. Due to the salt-dominated soil of the Atacama Desert, haloturbation and salt heave mechanisms control the formation of wedges and polygons under arid conditions. We present x-ray diffraction and x-ray fluorescence analyses of wedges from the central Atacama Desert that contain various calcium-sulfate phases as potential drivers for the wedge-growth activity. The formation of these wedges is connected to varying water activity. Hydration- and dehydration-induced phase transitions of calcium-sulfate phases result in significant volumetric changes in the soils. In combination with crystallisation pressure of (re-)precipitated salts from infiltrated solutions, these processes significantly contribute to the subsurface stress field. The upward stress release is assumed to express in a microtopographic signature of the surface, such as the polygonal patterned ground. In order to investigate the polygon-wedge system under arid conditions, we will present a combination of sedimentological, mineralogical, and geochemical analyses of subsurface wedges from the central Atacama Desert. We also present data constraining the formation age of calcium sulfate-dominated wedges that formed within the El Diablo Formation of Miocene age.</p>

Cultural Layer in the Stone Age Sites of Northeastern Siberia

The phenomenon of the cultural layer is a fundamental concept of archaeology and the main object of study in the practice of field research. Despite this, its definition, surprisingly, still remains undeveloped. The widely known classical definition leaves many important questions unanswered. Thus, what about the horizon, formed in the past by redeposition of material, especially if this is not obvious? Can the bone-bearing horizon (for example, bone deposit of the mammoth “graveyard”) definitely human-created but lacking (completely or almost completely) of formal artifacts be regarded as a cultural layer? What about areas of primary archaeological contexts, the elements of which retain their original structure and interconnection, but have lost their original spatial position along with the block of matrix sediments? In similar cases, except for burial structures, the concept of culture-bearing deposits, representing a specific geological formation, will be much more universal. Then culture-bearing deposits are deposits locally enriched with traces of past human activities (artifacts, technological waste, biological remains, structures, i. e., cultural remains sensu lato) as a result of the transfer and accumulation of matter in the process of lithogenesis. It should be emphasized that up to 65 % of the territory of Russia is the permafrost area, while that of the former permafrost zone was significantly larger and included currently unfrozen areas. The culture-bearing deposits of the Stone Age sites of the Late Pleistocene age represented in these regions undoubtedly experienced the impact of cryogenic processes. The study of the Stone Age sites in Eastern Siberia provides the richest opportunities and material for the development of this issue.

Analysis of ways to combat the sticking of rocks on the working equipment of mining machines

The article discusses ways to reduce energy consumption in the open-pit mining of minerals in the conditions of Kuzbass by reducing the sticking to the working automobile equipment and excavator complexes. When excavating and transporting cohesive rocks, due to a sharp change in climatic conditions, adhesion-cryogenic processes occur (sticking, freezing on excavator buckets, dumpcars, conveyor belts, dump truck bodies, etc.). This significantly reduces the efficiency of excavating and transport complexes. In this paper, we consider the adhesion-cryogenic processes affecting the rock, methods of anti-sticking for the selection of optimal solutions.