Periglacial Environments Research Articles

Deglaciation Rate of Selected Nunataks in Spitsbergen, Svalbard—Potential for Permafrost Expansion above the Glacial Environment

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.

Cosmogenic10Be and36Cl geochronology of cryoplanation terraces in the Alaskan Yukon-Tanana Upland

ABSTRACTCryoplanation terraces are prominent but enigmatic landforms found in present and past periglacial environments. Geomorphologists have debated for more than a century over processes involved in the formation of these elevated, step-like, bedrock features. Presented here are the first numerical surface exposure ages and scarp retreat rates from cryoplanation terraces in the Yukon-Tanana Upland (YTU) in Alaska, part of unglaciated eastern Beringia, obtained from terrestrial cosmogenic nuclides (TCN) in surface boulders. Ages comprise six10Be TCN ages from two terrace treads near Eagle Summit and six36Cl ages from two treads on Mt. Fairplay. Based on these exposure ages, scarps at both locations were last actively eroding from 49 to 22.4 ka. Both locations exhibit time-transgressive development, particularly near scarp-tread junctions. Boulder exposure ages and distances between sampled boulder locations were used to estimate scarp retreat rates of 0.11 to 0.56 cm/yr. These numerical exposure ages presented here demonstrate that the cryoplanation terraces in the YTU are diachronous surfaces actively eroding during multiple cold intervals. With these results, hypotheses for cryoplanation terrace formation are discussed and evaluated for the YTU, including those based on geologic structure, nivation, and the influence of permafrost.

Leyes de presupuestos mínimos de protección ambiental. Sobre glaciares, humedales y la emergencia del carácter político de categorías despolitizadas

In this article we analyze the ways in which certain categories are re-politicized in the processes of formulation of laws on minimum standards for environmental protection in Argentina. To do so, we focus our study on two specific environmental regulations: the “Glaciers Law” and the “Wetlands Law”. We resume the perspectives that highlight the fact that any conservation process is not only ecological, but also political, and through a documentary analysis supplemented with ethnographic interviews and instances of participant observation we show how the political nature of diverse categories linked to the domain of ‘the natural’, such as ‘glacier’, ‘periglacial environment’ or ‘wetland’, emerge in the processes of formulation of environmental regulations. If the post-political condition aims to empty the political arena of any disagreement or radical critique, we agree with those who maintain that the reemergence of the political character of this type of category demonstrates the omnipresence of power relations and their immanence in a political field. And we argue that it constitutes a necessary first step in order to think about alternatives that could modify the social relations that make possible the current regimes of appropriation of nature.https://doi.org/10.25260/EA.20.30.1.0.971

Icelandic permafrost dynamics since the Last Glacial Maximum – model results and geomorphological implications

Iceland’s periglacial realm is one of the most dynamic on the planet, with active geomorphological processes and high weathering rates of young bedrock resulting in high sediment yields and ongoing mass movement. Permafrost is discontinuous in Iceland’s highlands and mountains over c. 800 m a.s.l, and sporadic in palsa mires in the central highlands. During the late Pleistocene and Holocene, Iceland’s periglacial environment varied considerably in time and space, dominated by glacial fluctuations and periglacial processes. To evaluate the dynamics of permafrost in Iceland since the last deglaciation, we use the output of a coupled climate/ice sheet model to force a transient permafrost model (CryoGRID 2) from the Last Glacial Maximum (LGM) through to the present. We find that permafrost was widespread across the deglaciated areas of western, northern and eastern Iceland after the LGM, and that up to 20% of Iceland’s terrestrial area was underlain by permafrost throughout the late Pleistocene. This influenced geomorphological processes and landform generation: the early collapse of the marine-based ice sheet together with the aggradation of permafrost in these zones initiated the formation of abundant and now relict rock glaciers across coastal margins. Permafrost degraded rapidly after the Younger Dryas, with a marked impact on slope stability. Permafrost that formed during the Little Ice Age is again thawing rapidly, and an escalation in slope failure and mass-movement might be currently underway. Our study demonstrates that large regions of Iceland have been underlain by permafrost for millennia, facilitating landform development and influencing the stability of steep slopes.

Periglacial water paths within a rock glacier‐dominated catchment in the Stepanek area, Central Andes, Mendoza, Argentina

AbstractIn the region of the Stepanek rock glacier (69°19′/69°26′W, 32°55′/32°59′S), in the Province of Mendoza, Argentina, seasonal hydrochemical monitoring was carried out between 2013 and 2017. This paper describes underground and surface water flow, and their hydrochemistry, and provides an overview of how groundwater interacts with the rock glacier. The cryogenic basin of the study area where the hydrological flows originate has a surface area of 11.5 km2. The Stepanek rock glacier fills the valley and its permafrost influences water flow. Isotopic analyses of surface ephemeral streams and groundwater were made. Characteristic, naturally occurring δ2H and δ18O signatures of these samples indicate strongly that they are fed from within permafrost from the rock glacier, in response to the degradation of permafrost and melting of ground ice. Elevated values of Ni2+, Cd2+ and Zn2+ were detected in the meltwater runoff. Due to lithological factors, the Andean periglacial environment may indicate altitudinal differences in the hydrogeochemical results. Our hydrogeochemical research allows the interpretation of different water flows, directly observed or indirectly deduced, which cross the rock glacier. The new information allows for the development of a new conceptual rock glacier model that includes different flow paths. It is expected that this will become more important due to ongoing climate change.

Headwaters’ Isotopic Signature as a Tracer of Stream Origins and Climatic Anomalies: Evidence from the Italian Alps in Summer 2018

Glaciers are shrinking due to global warming, resulting in a diminishing contribution of ice and snowmelt to headwaters and subsequent consequences to freshwater ecosystems. Within this context, we tested whether water-stable isotopes are spatio-temporal tracers of (i) water in high altitude periglacial environments, being the isotopic signature of surface water inherited from the snow/icemelt, groundwater, and rainfall; and (ii) regional (year-specific) meteorological conditions, being the isotopic signature of precipitations affected by air temperature, humidity and aqueous vapour origin, ascribing stable isotopes to the list of “essential climate variables″ (ECVs). To this end, we investigated the ionic and isotopic composition (δ18O and δ2H) of six high-altitude streams and one pond in the Italian Alps (Noce and Sarca basins) during the ablation season in 2018. Differences between habitat types (pond, kryal, rhithral, krenal) were detected. More negative values of δ18O and δ2H were recorded in the kryal and glacio-rhithral sites, dominated by ice and snowmelt, in early summer. Less negative values were recorded in these sites in late summer, as well as in the krenal sites, which were dominated by groundwater and rainfall inputs. The isotopic results also show that the complex alpine orography influences air masses and moisture, ultimately resulting in isotopic differences in the precipitations of neighboring but distinct catchments (Sarca and Noce basins). On average, less negative values were recorded in the Sarca basin, characterized by a higher contribution of precipitation of Mediterranean origin. In general, isotopic results of the entire water population appeared to be strongly influenced by the regional climatic anomaly of 2018, which was anomalously warm. Therefore, the study will provide additional information for the climate change debate, proposing water isotopes as ECVs for assessing change in a warmer future.

Time‐transgressive cryoplanation terrace development through nivation‐driven scarp retreat

AbstractCryoplanation terraces are elevated bedrock features resembling giant staircases, with alternating steep scarps and shallow sloping treads. These landscape‐scale features have long been associated with periglacial environments, but the processes involved in their formation remain vaguely specified and contentious. The two leading hypotheses for the formation of cryoplanation terraces are centered on: (1) geologic structure; and (2) nivation‐driven scarp retreat. The nivation‐formation hypothesis invokes scarp retreat under erosion processes associated with late‐lying snowbanks. To test whether cryoplanation terraces develop through scarp retreat, six relative weathering indices (fracture counts, Cailleux roundness, Cailleux flatness, Krumbein sphericity, rebound, and weathering rind thickness) were measured across well‐developed terraces in unglaciated eastern Beringia (central and western Alaska) at Mt Fairplay, Eagle Summit, and Skookum Pass. Statistically significant differences in relative weathering indices detected through chi‐square and multiple‐comparison procedures indicate that material is less weathered closer to scarps, i.e. that these areas were more recently exposed than those distant from the scarp. Based on these findings, a refined model of time‐transgressive cryoplanation terrace development through nivation‐driven scarp retreat is proposed. This new qualitative model addresses the removal of weathered material from terrace treads down side slopes through piping and gravity‐driven mass‐wasting processes. © 2019 John Wiley & Sons, Ltd.

Detection and Delineation of Sorted Stone Circles in Antarctica

Sorted stone circles are natural surface patterns formed in periglacial environments. Their relation to permafrost conditions make them very helpful for better understanding the past climates where they were formed and have evolved and also for monitoring current underlying processes in case circles are active. These metric scale patterns that occur in clusters of tens to thousands of circular elements, can be more comprehensively characterized if automated methods are used. This paper addresses their identification and delineation through the development and testing of a set of automated approaches, namely, template matching, sliding band filter, and dynamic programming. All of these methods take advantage of the 3D shape of the structures conveyed by digital elevation models (DEM), built from ultra-high resolution imagery captured by unmanned aerial vehicles (UAV) surveys developed in Barton Peninsula, King George Island, Antarctica (62°S). The best detection results achieve scores above 85%, while the delineations are performed with errors as low as 7%.

Small-scale lobate hillslope features on Mars: A comparative 3D morphological study with terrestrial solifluction lobes and zebra stripe lobes

Small-scale lobes (SSL) observed at the surface of Mars are thought to be the result of solifluction. Hence, their existence has important implications for our understanding of recent climate history, the distribution of thaw liquids and its geomorphic effects, as water is believed not to have been recently stable at the martian surface. These small-scale lobes are limited to sloping terrains and often occur alongside polygonal patterned ground attesting to the presence of ice in the environment. In this study, we perform a comparative 3D morphometric analysis of the lobes on Mars with terrestrial analogues. We use data from High Resolution Imaging Science Experiment (HiRISE) camera in order to create Digital Terrain Models (DTMs) on Mars at 1 m/pix. For the terrestrial analogues, we use DTMs and orthophotos from five periglacial environments with solifluction lobes and from one site with lobate features found in the Atacama Desert. The lobate features in the Atacama Desert are found within features called “zebra stripes”, which are apparently unique to the Atacama and are now generally accepted to be the result of seismic shaking. We show that SSL on Mars overlap morphometrically with terrestrial solifluction lobes, and are less similar to zebra stripe lobes. The majority of martian SSL occur below the angle of repose which demonstrates that a dry fall mechanism cannot be responsible for their formation and that lubrication of the subsurface is required. We found that martian SSL only occur on slopes greater than ~10°, a constraint not observed for terrestrial solifluction lobes nor zebra stripe lobes in Atacama. We hypothesise that this apparent constraint does not result from the lowered gravity on Mars, but instead from differing soil properties and/or thermal regime between Mars and Earth which affects the slope at which creep can initiate. We cannot rule out a role of CO2 sublimation in lobe-formation based on our terrestrial measurements.

Assessing the impact of ground ice degradation on high mountain lake environments (Lago Nero catchment, Swiss Alps)

In high mountain hydrosystems, glacial meltwater composition is potentially affected by the degradation of alpine permafrost terrains and ground ice bodies releasing atmospheric pollutants that have been stored in permafrost terrains for several decades. In this study we investigate the potential local permafrost distribution as well as the physical and chemical ground water characteristics of the periglacial environments of the Lago Nero (“Black Lake”) catchment, a high alpine basin located in the Southern Swiss Alps. Our approach combines in situ geological and geomorphological mapping, potential permafrost distribution modelling, a thermal monitoring of ground surface temperatures and the study of the meltwater chemistry of an intact rock glacier (active or inactive rock glacier, i.e. containing ice) and several perennial ice patches. The comparison of elemental concentrations between the periglacial terrains and the Lago Nero outflow unveiled the presence of atmospheric chemicals in the meltwater. Considering the temporal concordance between the recorded peak of sulphur deposition between 1965 and 1980 and the last identified period of positive glacier mass balance occurred in the region (1961–1985), we argue that the enhanced melting of ground ice related to the recent severe warming is nowadays releasing “legacy” pollutants that have been stored in the cryosphere for several decades.

IMPACT OF TECTODYNAMIC AND MORPHODYNAMIC FACTORS ON THE SUSTAINABLE DEVELOPMENT OF THE SHPAT MOUNTAINOUS RIDGE

Shpat mountainous ridge represents a morphological unit with extremely prominent natural borders and rich natural resources. This abstract presents the natural potentials of Shpat mountainous ridge and a synthesized analysis of key aspects of tourism, mineral and water resources, forests and pastures management, etc. Shpat unit, is integral part of Bukanik ultrabasic massive, where are explorated cooper resources. The geological content of this mountain, contribues the mesozoic ultrabasic and flysch, calcareous rocks and quaternary deposition are also present. The morphologic and morphogenetic complex of the relief was created during the tectogenic period, especially during the tecto-orogenesis, where as consequence diverse magmatic, terrigenous and carbonates rocks were created. Structural relief landforms, are structural benches, flat surfaces formed in the aclinal structure, structural surfaces, denudational surfaces and concave fragment of front of the cuestas. The karstic surface forms were developed on limestones of different age and character. There is a conspicuously small number of dolines on the surface of the hardly dissolvable crystalline limestone, and the debris covering the surface is high enough for agriculture. The water infiltrating on the plateau surfaces in the karst springs. The knowledge of present morphodynamics implies features concerning the positive and restrictive role of each factor, which, by association, defines the potential of some gropus of processes and state of morphologic hazards in certain area. Such analyses multiplied in the last couple of years, when the occurrence of some mass wastings determined many geomorphologic risk situations allover Shpat mountainous ridge. The climate by regional and local differences of the weathering elements favorable to the development of morphological processes. In periglacial environments solifluction frequently occurs in association with permafrost or seasonally frozen ground, and under these circumstances it is more specifically described as gelifluction. Snow provides both and as ground insulation. The erosional potential of nivation is controlled primarily snow thickness or absence underlying permafrost. Cryoplanation terraces (also known as altiplanation terraces) are level or gently sloping surfaces found in the periglacial zone which are cut into bedrock on hill summits or upper peaks. The natural potentials of Shpat mountainous ridge have been analyzed as key elements of this area for sustainable development. The effects of the use of the natural resources and their influence on the economic structure have been analyzed defining the directions of the development on perspective of the rural area. The current developments at the agricultural rural area have produced changes to the physical-geographical elements, accelerating the pace of slope processes, where the predominant part of the settlements is established on the terrace levels, causing environmental degradation.

Periglacial environments and frozen ground in the central Pyrenean high mountain area: Ground thermal regime and distribution of landforms and processes

AbstractThe periglacial belt is located in the highest parts of temperate mountains. The balance between mean air and ground temperatures and the presence of water determine the effectiveness of periglacial processes related to permafrost, the active layer or seasonally frozen ground (SFG). This study combines thermal and geomorphological data obtained in four Pyrenean massifs (Infierno‐Argualas, Posets, Maladeta and Monte Perdido) to improve knowledge on the occurrence and distribution of frozen ground. The methodology used is based on the study of landforms as frozen ground indicators, mapping processes, ground temperature analysis, basal temperature of snow, thermal mapping and geomatic surveys on rock glaciers and protalus lobes. In the Pyrenean high mountain areas the lower limit of frozen ground is at ~2,650m a.s.l., possible permafrost appears above 2,650m a.s.l. on north‐ and south‐facing slopes, and probable permafrost is dominant above 2,900m a.s.l. Unfrozen ground with cold‐associated geomorphological processes reach 2,900m a.s.l. and unfrozen and frozen ground distribution points to a patchy pattern throughout the periglacial belt. The most widespread frozen grounds are SFG. The thermal data, mean annual ground temperature, cold season temperatures, bottom temperature snow measurements, freeze/thaw cycles and distribution of landforms permit the establishment of a periglacial land system divided into three main belts: infraperiglacial, middle periglacial and supraperiglacial. The large number of processes and landforms that are involved and their altitudinal and spatial organization make up a complex environment that determines the geoecological dynamics of high mountain areas.

Two-dimensional inversion of wideband spectral data from the capacitively coupled resistivity method – first applications in periglacial environments

Abstract. The DC resistivity method is a common tool in periglacial research because it can delineate zones of large resistivities, which are often associated with frozen water. The interpretation can be ambiguous, however, because large resistivities may also have other causes, like solid dry rock. One possibility to reduce the ambiguity is to measure the frequency-dependent resistivity. At low frequencies (< 100 Hz) the corresponding method is called induced polarization, which has also been used in periglacial environments. For the detection and possibly quantification of water ice, a higher frequency range, between 100 Hz and 100 kHz, may be particularly interesting because in that range, the electrical properties of water ice exhibit a characteristic behaviour. In addition, the large frequencies allow a capacitive coupling of the electrodes, which may have logistical advantages. The capacitively coupled resistivity (CCR) method tries to combine these logistical advantages with the potential scientific benefit of reduced ambiguity. In this paper, we discuss CCR data obtained at two field sites with cryospheric influence: the Schilthorn massif in the Swiss Alps and the frozen Lake Prestvannet in the northern part of Norway. One objective is to add examples to the literature where the method is assessed in different conditions. Our results agree reasonably well with known subsurface structure: at the Prestvannet site, the transition from a frozen lake to the land is clearly visible in the inversion results, whereas at the Schilthorn site, the boundary between a snow cover and the bedrock below can be nicely delineated. In both cases, the electrical parameters are consistent with those expected from literature. The second objective is to discuss useful methodological advancements: first, we investigate the effect of capacitive sensor height above the surface and corroborate the assumption that it is negligible for highly resistive conditions. For the inversion of the data, we modified an existing 2-D inversion code originally developed for low-frequency induced polarization data by including a parametrization of electrical permittivity. The new inversion code allows the extraction of electrical parameters that may be directly compared with literature values, which was previously not possible.

Rockslides and rock avalanches in the Central Andes of Argentina and their possible association with permafrost degradation

AbstractThe identification of hazardous slopes with degrading permafrost is a key task in the mountain periglacial environment. If rockslides have previously been preconditioned by rock wall permafrost, similar events may be triggered from present unstable rock walls. An inventory of rockslides and rock avalanches in the austral part of the Santa Cruz river basin (31°40′–31°50′S, 70°30′–70°10’W), San Juan, Argentina, was made. The study area comprises a surface of approximately 432 km2 (50% above 3,500 m asl); 15 rockslides, 12 complex rockslides evolving to rock avalanches and 19 rock avalanches were identified. The deposits were analyzed with remote sensory imagery and during fieldwork in order to study processes under permafrost degradation caused by global warming. Rock sampling procedures and laboratory rock‐resistivity testing were also carried out. We characterized the detachment scars and deposits for two rockslides. Two different mechanisms were identified. In one rockslide, shallow active layer detachment was favored by shear‐displacement along pre‐existing joints, as a result of short‐term periods of climate warming. In the other, long‐term permafrost degradation favored a deeper failure process. The studied landslide processes could not be explained by permafrost degradation alone. Faults, the geometric arrangement of their structural elements and seismic activity may contribute to trigger these phenomena. It is expected that the magnitude and frequency of rockslide hazards will increase during the 21st century.

Abrasion rates of ventifacts

Although ventifacts are often utilized to determine past and present wind directions and sediment mobilities in arid, coastal, and periglacial environments, their morphodynamics have not been well understood. In this study, based upon the principles of classical mechanics, the abrasion rate of ventifact is analytically expressed by the elastic properties of rock or mineral components and the mass flux density of sediment transported by wind. The unknown abrasion coefficient can be estimated via wind tunnel experiments. The practicability of this novel formula is shown by the calculation of short-term abrasion depth of ventifacts over a desert pavement. It is expected that the current work will improve the quantitative reconstruction of paleo-environments and paleo-climates using ventifacts.

A palaeoclimatic record from the Ledo-Paniselian Aquifer in Belgium – Indications for groundwater recharge and flow in a periglacial environment

Understanding the mechanisms of groundwater recharge and flow in periglacial environments remains enigmatic. Methane releases from melting permafrost in a warming world are a hot topic in contemporary climate research. Noble gas analyses have been proposed to study methane-driven degassing in lakes as well as in permafrost terrains. The Ledo-Paniselian aquifer is shown to provide an analogue for such processes, from the last period of global warming after the LGM. It is postulated that recharge from methane bubbling thermokarst lakes to groundwater took place, and can be recognized by a specific signature in the groundwater. The Ledo-Paniselian aquifer offers unique opportunities to study periglacial groundwater recharge during the LGM, as it was located in the permanent permafrost area to the south of the ice sheet at that time. It contains Holocene and Pleistocene groundwaters, which are separated by a recharge gap, referring to permafrost during the LGM. This is confirmed by noble gas temperature (NGT) data. In the samples immediately upstream of this gap, several potential indicators for the specific methanogenic recharge conditions from thawing permafrost are being put forward, based on noble gases, chemical and isotopic data.Immediately upstream of the age gap, groundwaters show strikingly deviating HCO3−, SO42−, δ13C, δ18O and δ2H compared to the regional trend, while their 14C model ages are too young, and NGTs seem too high. These samples are affected by degassing, which is not an artefact of sampling, and which, according to their radiogenic helium concentrations, occurred early on, during recharge or shortly thereafter. The origin of these samples could be explained by the conditions prevailing as the permafrost thawed, and groundwater recharge could resume. It is inferred that the degassed samples were infiltrated during or shortly after the LGM, when recharge from methane bubbling thermokarst lakes to groundwater took place, associated to the melting permafrost.

Seasonal dynamics of a permafrost landscape, Adventdalen, Svalbard, investigated by InSAR

Nordenskiöld Land in Central Spitsbergen, Svalbard is characterized as a high latitude, high relief periglacial landscape with permafrost occurring both in mountains and lowlands. Freezing and thawing of the active layer causes seasonal frost heave and thaw subsidence, while permafrost-related mass-wasting processes induce downslope ground displacements on valley sides. Displacement rate varies spatially and temporally depending on environmental factors. In our study, we apply Satellite Synthetic Aperture Radar Interferometry (InSAR) to investigate the magnitude, spatial distribution and timing of seasonal ground displacements in and around Adventdalen using TerraSAR-X StripMap Mode (2009–2017) and Sentinel-1 Interferometric Wide Swath Mode (2015–2017) SAR images. First, we show that InSAR results from both sensors highlight consistent patterns and provide a comprehensive overview of the distribution of displacement rates. Secondly, two-dimensional (2D) TerraSAR-X InSAR results from combined ascending and descending geometries document the spatial variability of the vertical and east-west horizontal displacement rates for an average of nine thawing seasons. The remote sensing results are compared to a simplified geomorphological map enabling the identification of specific magnitudes and orientations of displacements for 14 selected geomorphological units. Finally, June to December 2017 6-day sampling interval Sentinel-1 time series was retrieved and compared to active layer ground temperatures from two boreholes. The timing of the subsidence and heave detected by InSAR matches the thawing and freeze-back periods measured by in-situ sensors. Our results highlight the value of InSAR to obtain landscape scale knowledge about the seasonal dynamics of complex periglacial environments.

Detailed alluvial fan geomorphology in a high-arctic periglacial environment, Svalbard: application of unmanned aerial vehicle (UAV) surveys

ABSTRACT A 1:850 detailed map of the geomorphology of the Dynamisk Creek alluvial fan on Svalbard was produced based on very high-resolution data collected using an unmanned aerial vehicle (UAV) in 2014. The map documents features within the surface of the fan (0.35 km2), emphasizing their relative temporal activity. Fluvial flows were the most important geomorphological processes responsible for aggradation and modification of the fan surface. However, at present most of the fan area is inactive (about 75% of the whole fan surface) and stabilized by vegetation and mosses. Furthermore, in some places, niveo-aeolian (6% of the fan surface) and snow avalanches (1.5% of the fan surface) deposits have been noticed. In addition to the map, detailed morphometric characteristics of the fan and its catchment are also provided. The presented work illustrates the enormous usefulness of small UAVs for the study of fan surfaces in periglacial environments.

Deformation characteristics and multi-slab formation of a deep-seated rock slide in a high alpine environment (Bliggspitze, Austria)

This study presents the results of a more than 10-year-long field investigation and remote sensing monitoring campaign of a highly active deep-seated rock slide located in a glacial to periglacial environment (Bliggspitze, Tyrol, Austria). Data concerning (i) the terrain surface displacements based on imagery (webcam time-lapse, ortho-images) and both terrestrial and airborne laser scanning, and (ii) the geological-structural and geomorphological situation were analysed to develop a geological-geometrical model of the rock slide and to study the temporally variable activity behaviour and the formation of individual rock slide slabs. Results clearly show that at least seven rock slide slabs were formed at different times and under different slope stability conditions. Some of these rock slide slabs were displaced at slow to moderate velocities and reached scarp offsets of several tens of metres, whereas other, shallower slabs collapsed and formed extremely rapid rock falls and avalanches. Generally, the rock slide is affected by rock mass cataclasis, fracturing and loosening, which in turn cause extensive mass loss accompanied by debris accumulation at lower parts of the slope. The cause for the development of the Bliggspitze rock slide is poorly understood. However, there are clear indications that permafrost degradation and/or glacial retreat, particularly at the foot of the slide, during the recent decades may have adversely affected the slope stability situation.

Late Vistulian and Holocene development of litho-morpho-pedogenic processes in the southern Baltic coastal zone: A case study from Dębina, northern Poland

The study aimed to reconstruct major phases of the litho-morpho-pedogenic processes in the southern Baltic coastal zone near Dębina in northern Poland. Five profiles of fossil soils in the coastal cliff were described, sampled and analysed using standard procedures. The studied outcrop covers a sequence of deposits, including the basal till of the Świecie Stadial (MIS 4) of the Vistula Glaciation, the ablation till of the Pomeranian Phase (MIS 2) of the Vistula Glaciation, the thin cover of glacilimnic sand, the lacustrine sediments filling the palaeolake basin, and aeolian deposits of varied age. A sequence of paleosols developed successively within these deposits during the Late Vistulian and Holocene (MIS 1). The initialization of soil-forming processes occurred under the influence of periglacial environment and pioneer tundra vegetation. Endostagnic Podzols (Abruptic, Epiarenic, Endoloamic, Endodensic) developed within the plateau, and they have some features typical for periglacial environments (e.g. the presence of a cryoilluvial horizon, the poor humification of soil organic matter, the low abundance in N and P, and the vertical displacement of P). The basin of a small lake has been filled successively with sediments and Dystric Endocalcaric Katostagnic Fluvisols (Arenic, Humic, Endolimnic) developed from these sediments during the Late Vistulian and Early Holocene. The previously mentioned soils were buried by sandy cover in the Early Subatlantic due to intensification of aeolian processes. Ortsteinic Podzols (Pantoarenic) developed within a newly formed sandy cover. A fossil fireplace preserved in the top of these soils constitutes evidence of human activity dating back almost 2000 years. Ortsteinic Podzol (Pantoarenic) are dissected by a dry valley that developed as a result of some fluvial episode, perhaps induced by human activity. It was subsequently filled with aeolian sands, and Dystric Arenosols (Aeolic, Ochric) developed within them. Ortsteinic Podzol (Pantoarenic) and Dystric Arenosols (Aeolic, Ochric) were buried approximately five centuries ago. Our findings for the studied cliff section correlate well with results of other authors concerning the postglacial dynamics of morphogenetic processes. The studies provide significantly enriched geomorphological knowledge related to the formation of relief in the study area, with pedological aspects.