GM10.2 | Cold Regions Geomorphology
EDI
Cold Regions Geomorphology
Co-organized by CR4
Convener: Isabelle Gärtner-Roer | Co-conveners: Sven Lukas, Clare Boston, Jenna SutherlandECSECS, Andreas Kellerer-Pirklbauer
Orals
| Tue, 16 Apr, 08:30–10:15 (CEST)
 
Room G1
Posters on site
| Attendance Wed, 17 Apr, 10:45–12:30 (CEST) | Display Wed, 17 Apr, 08:30–12:30
 
Hall X3
Orals |
Tue, 08:30
Wed, 10:45
Present-day glacial and periglacial processes in cold regions, i.e. arctic and alpine environments, provide modern analogues to processes and climatic changes that took place during the Pleistocene, including gradual retreat or collapse of ice sheets and mountain glaciers, and thawing and shrinking of low-land permafrost. Current geomorphological and glaciological changes in mid-latitude mountain ranges could also serve as a proxy for future changes in high-latitude regions within a context of climate change. Examples are speed-up or disintegration of creeping permafrost features or the relictification of rock glaciers.

For our session we invite contributions that either:
1. investigate present-day glacial and/or periglacial landforms, sediments and processes to describe the current state, to reconstruct past environmental conditions and to predict future scenarios in cold regions; or
2. have a Quaternary focus and aim at enhancing our understanding of past glacial, periglacial and paraglacial processes, also through the application of dating techniques.

Case studies that use a multi-disciplinary approach (e.g. field, laboratory and modelling techniques) and/or that highlight the interaction between the glacial, periglacial and paraglacial cryospheric components in cold regions are particularly welcome.

Orals: Tue, 16 Apr | Room G1

Chairpersons: Isabelle Gärtner-Roer, Sven Lukas, Andreas Kellerer-Pirklbauer
08:30–08:35
08:35–08:45
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EGU24-2308
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On-site presentation
Stefan Winkler

Rock glaciers as typical periglacial landforms in alpine environments constitute valuable palaeoclimatic indicators due to their connection to the climate-driven permafrost conditions responsible for both their initial formation and continuing activity. In particular for the Late Glacial/Early Holocene transition in cases local morphological evidence for glacial activity is sparse, targeting rock glaciers may successfully complement investigations on contemporaneous landform evolution or climatic variability in mountain regions. The Ben Ohau Range southeast of the Main Divide of the Southern Alps in New Zealand is an example where such conditions prevail. Only few studies focusing on chronological aspects, mostly older ones applying weathering-ring thickness as main dating technique, have been conducted on the rock glaciers occurring in considerable numbers in this selected mountain range to date. Consequently, the chronological data available remain limited.  

Following successful application during a previous pilot study, Schmidt-hammer exposure-age dating (SHD) regarded as suitable calibrated-age dating technique has recently been extensively applied in the Ben Ohau Range. Overarching aim of the related research project is to spatially expand and simultaneously improve the chronological data set for both initial formation and periods of morphodynamic activity of rock glaciers. The obtained chronological data are, furthermore, intended to eventually support the analysis of regional Holocene glacier activity in the Southern Alps.

Additional to SHD-sampling on various rock glaciers, published numerical TCND 10Be-ages from glacial landforms at two independent sites in the Ben Ohau Range have been utilised to establish a new regional SHD age-calibration equation. Including the abovementioned pilot study SHD age-estimates are now available for eight individual rock glaciers placed in three separate cirques/valley heads located in the middle and southern part of the range. These improved chronological constraints are based on no less than 16,500 sampled boulders on individual transversal rock glacier ridges and SHD age-calibration equation's control points. 

With SHD age-estimates for their initial formation of 11.4 ± 0.4 ka (Duncan Stream), between 9.4 ± 0.9 and 8.6 ± 0.8 ka (Double Basin), and between 11.8 ± 1.6 and 7.3 ± 0.8 ka (Irishman Stream) the studied rock glaciers appear to be significantly older than anticipated and previously reported. Some rock glaciers must have commenced their morphodynamic activity directly around the onset of the Early Holocene, what concurrently indicates that deglaciation of these cirques must have been completed at this point. Because the age difference between the innermost Late Glacial/Early Holocene moraines and the outermost rock glacier ridges sometimes averages only several hundred years, transition from glacial to periglacial processes must have been relatively rapid. With the palaeoclimatic interpretation of this development the significant precipitation gradient east of the Main Divide causing comparatively dry conditions in the middle and southern Ben Ohau Range needs to be taken into account.

Some of the studied rock glaciers are currently active, whereas others need to be classified as inactive. All seem, however, have experienced longer periods of activity during the Holocene.  

How to cite: Winkler, S.: Improved chronological constraints on rock glacier activity in the Ben Ohau Range, Southern Alps/New Zealand, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2308, https://doi.org/10.5194/egusphere-egu24-2308, 2024.

08:45–08:55
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EGU24-11592
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ECS
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On-site presentation
Hugo Watine, Simon Daout, Jérôme Lavé, and Marie-Pierre Doin

The Tibetan Plateau is characterized by a high periglacial landscape. The average annual surface temperature is below 0°C over most of the Plateau, so permafrost (permanently frozen ground) is present over most of its extent. Excess ice in the frost-sensitive materials of the active layer, above the permafrost, thaws during the summer and autumn months and freezes during the winter and spring months. These freezing and thawing phenomena lead to cyclic vertical movements of the surface. On the slopes, solifluction phenomena also related to freeze-thaw activity take place, associated to permanent horizontal displacements. Both movements can be measured by spatial geodesy techniques such as Synthetic Aperture Radar Interferometry (InSAR).

The high-altitude Tibetan Plateau, like the Arctic regions, is particularly sensitive to global warming, and recent studies  have documented an apparent acceleration of solifluction processes as well as permanent ground subsidence likely due to ice loss in permafrost. Here, we developed a methodology to analyse hillslope processes from multi-temporal InSAR data to further document this worrying trend, and confirm or not its relation with global and regional temperature increase or with glacier ice loss in Tibet. 

InSAR time series of surface deformation from 16 yr of Envisat (2003-2011) and Sentinel-1 (2014-2020) ESA satellite radar measurements have been built over an 80,000km2 area to study the permafrost evolution of the northeastern Tibetan Plateau. Time series exhibit three trends, (1) a linear trend of continuous deformation, (2) an annual cyclical deformation whose amplitude appears to (3) increase over time. We conducted an analysis of the annual cyclic and cumulative deformation from the InSAR time series and projected those three trends parallel and normal to the line of the greatest slope. Areas with poor constraints were masked based on hillslope aspect from synthetic tests. The measurements (seasonal cycles and cumulative deformation in the slope and normal) were correlated to the lithology, the nature of the surface formations (moraines, alluvial fans, etc.), the altitude, the slope, the curvature, and the orientation of the slopes, in order to characterize the distribution of these processes.

Our change of reference frame strategy proved effective in automatically extracting hillslope processes and quantifying their dynamics. Downward movements affect nearly all terrains, with velocities increasing in line with slope angles. Steeper displacements are observes in unconsolidated, frost-susceptible, and fine-grained sediments, exhibiting higher seasonal amplitude perpendicular to the slope. In contrast, for sedimentary and magmatic rocks that display lower seasonal amplitude, continuous creeping appears to be the primary downward displacement process. Permafrost degradation (long-term subsidence) appears more pronounced at higher altitudes (above 3800m) where one would expect to find the coldest annual average temperatures. We also illustrate significant increases in seasonal amplitude, potentially doubling within 5 years in intermontain basin. These findings suggest a recent degradation of the permafrost and a deepening of the active layer in the northeastern Tibetan Plateau, likely induced by global warming.

How to cite: Watine, H., Daout, S., Lavé, J., and Doin, M.-P.: InSAR monitoring of solifluction and permafrost evolution in the Northeastern Tibetan Plateau, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11592, https://doi.org/10.5194/egusphere-egu24-11592, 2024.

08:55–09:05
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EGU24-7901
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ECS
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On-site presentation
Marie Rolf, Inge Grünberg, Jennika Hammar, and Julia Boike

Rising temperatures have led to permafrost degradation throughout the Arctic. The melting of excess ground ice leads to a loss of structural support and consolidation of soils. As a consequence, the surface subsides, which, in turn, can accelerate further ground ice loss. Therefore, thaw subsidence is an important metric for monitoring permafrost degradation. With temperature rise reaching twice the Arctic and seven times the global average rate, warming trends in Svalbard are particularly high, leading to severe impacts on permafrost conditions. However, knowledge on subsurface permafrost changes in Svalbard is mostly limited to a few in situ observations. In this study, we aimed to spatially expand research on permafrost degradation by applying a multimethod approach to quantify thaw subsidence in the Bayelva basin (near Ny-Ålesund, Svalbard). First, during a field campaign in summer 2023, we measured Global Navigation Satellite System (GNSS) points and calculated elevation changes since an earlier GNSS survey in 2019. Second, we coregistered and differenced high-resolution digital elevation models (DEMs) for a period of more than 80 years (from 1936, 1995, 2008, 2010, 2019, and 2020) to identify spatial patterns of thaw subsidence over a larger area. Third, we analysed how thaw subsidence relates to various terrain attributes and land cover. By employing these methods, we clearly detected thaw subsidence in the Bayelva basin. The GNSS measurements showed a spatially averaged subsidence of 2.7 cm between 2019 and 2023. With DEM differencing, we observed annual surface subsidence in the order of metres for areas of glacial retreat, in the order of decimetres for moraines, and up to a few centimetres for tundra areas in the glacier foreland. We furthermore detected spatial variations in thaw subsidence throughout the tundra. We conclude that surface subsidence is an ongoing, widespread, and important process in Svalbard’s permafrost landscapes. In this study, we demonstrate the challenges of DEM coregistration in areas with a lack of stable terrain. Nevertheless, our results highlight the potential of GNSS measurements and DEM differencing for quantifying thaw subsidence in the Arctic.

How to cite: Rolf, M., Grünberg, I., Hammar, J., and Boike, J.: Quantifying thaw subsidence in a permafrost landscape (Bayelva basin, Svalbard), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7901, https://doi.org/10.5194/egusphere-egu24-7901, 2024.

09:05–09:15
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EGU24-792
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ECS
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On-site presentation
Axel Noblet, Anna Grau Galofre, and Gordon R. Osinski

Investigating the regional distribution of ice-wedge polygons allows for the estimation of permafrost conditions in periglacial environments, assess its vulnerability to degradation and anticipate how ice-wedge polygons will respond to climate change. Here we investigate the spatial distribution, substrate, and geometric properties of ice-wedge polygons as well as their relationship with other periglacial landforms in Western Greenland near the settlement of Kangerlussuaq. Ice-wedge polygons are networks of interconnected ice-filled fractures that develop in periglacial environments during cyclical drops of temperatures. To investigate the current state of ice-wedge polygons near Kangerlussuaq we conducted a field campaign in July 2023 as part of the Europlanet Transnational Access program. We mapped and characterized ice-wedge polygons using a series of 2004 aerial photographs and our field observations. Polygons in our research area are decameter scale and are found on hillslopes in a sandy loess material that is overlain by a layer of peat and vegetation. We have observed polygons on hillslopes as steep as 36° which suggests that the slope material in our study area is stable and resistant to solifluction. While the polygons themselves did not display any substantial morphological modification between the 2004 aerial photographs and our study, we observed signs of rapid slope modification in the form of active layer detachment slides (ALDS). These relatively small slides (1.2-1.5 × 102 m3) overprinted ice-wedge polygons morphologies downslope, effectively obscuring the polygons without removing them. The frequency of ALDS in permafrost area could increase under the current context of warming temperatures in the Arctic, which would locally affect the ability of any satellite or aerial based studies to detect ice-wedge polygons on the affected hillslopes. We find that polygons are anti correlated with earth hummocks, another type of periglacial landform that develops in poorly drained sites. This suggests that the presence of polygons on a slope modifies the local hydrology by increasing the drainage efficiency, which inhibits the formation of earth hummocks. Our field observations indeed indicate that polygon troughs modify the local drainage and act as water tracks. We observed soil piping and mobilization of small volumes (~1m3) of subsurface material along these troughs. This removal of material is probably facilitated by the absence of coarse material in the sandy loess that composes these slopes. While the extensive vegetation cover in our study area most probably increases the ground resistance to surface erosion via root consolidation and absorption of ground moisture, we suggest that subsurface erosion along polygon troughs will increase if the magnitude of water flow on these hillslopes increases, which should be expected under the current context of wetter-than-normal conditions in the Arctic due to climate change. Finally, we find that 64 % of all polygonised areas we mapped are found on north-west facing hillslopes and 76% are found on slopes steeper than five degrees, which indicate that topography and insolation have been the most likely controls for the development of ice-wedge polygons in this region.

How to cite: Noblet, A., Grau Galofre, A., and Osinski, G. R.: Distribution of ice-wedge polygons in Kangerlussuaq, Western Greenland, and association with other periglacial landforms , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-792, https://doi.org/10.5194/egusphere-egu24-792, 2024.

09:15–09:25
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EGU24-12056
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ECS
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Virtual presentation
Michelle Fame, Kristin Chilton, James Spotila, Meredith Kelly, and Summer Caton

The deposition of large, resistant boulders on hillslopes and in channels can have an armouring effect on the landscape leading to a decrease in erosion rates, a decrease in the efficiency of downslope sediment transport, and a coeval mismatched increase in slope angle. Such boulder accumulations are a significant component of hillslopes and channels in the southern Appalachian Mountains and influence the landscape's morphology. It has long been speculated that these boulder deposits originated during Quaternary glacial advances under the influence of periglacial processes operating in cold regions south of the maximum extent of the Laurentide Ice Sheet. However, no prior work has tied these features to a specific time or climatically modulated mechanism. By testing and refining the hypothesis of the periglacial origin of these relict boulders and the mechanisms driving their initial deposition and subsequent reworking we hope to contribute to our understanding of the climatically correlated timescales over which contemporary warming can be expected to be a dominating influence on modern boulder armoured periglacial alpine and arctic landscapes.

In this study, we investigated the lifecycle of such boulder deposits by determining cosmogenic 10Be exposure ages from large boulders on hillslopes and in channels in the Virginia Appalachians, United States. The correlation between the resulting boulder exposure ages (101.7 ± 6.9 ka to 10.8 ± 0.8 ka; n = 23) and the most recent Wisconsin Glacial Stage and subsequent deglaciation (~115 – 11.7 ka) supports their periglacial origin. The lack of exposure ages corresponding to the Last Interglacial Stage or following Wisconsin ice retreat suggests interglacial non-deposition and stability. The absence of exposure ages from the penultimate Illinoian or older Quaternary Glacial Stages suggests that periglacial hillslope processes allow the landscape to be resurfaced with large boulders during each return to cold climate conditions. This cyclic resurfacing of hillslopes and channels is an example of how climatic oscillations insert disequilibrium into the landscape cycle and contributes to our appreciation of the timescales over which climate change may impact boulder landscapes in modern periglacial environments.

How to cite: Fame, M., Chilton, K., Spotila, J., Kelly, M., and Caton, S.: The lifecycle of a relict periglacial boulder landscape, southern Appalachians, USA, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12056, https://doi.org/10.5194/egusphere-egu24-12056, 2024.

09:25–09:35
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EGU24-12880
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On-site presentation
Piotr Owczarek, Magdalena Opała-Owczarek, Pavla Dagsson-Waldhauserova, Randall J. Schaetzl, and Krzysztof Migała

Arctic and sub-Arctic terrestrial environments often have bare surfaces, thin and poorly developed soils, large amounts of loose sediment, and low and sparse vegetation. The sensitivity of these sites to modern climate change is reflected, among other things, in an increase in the activity of erosion processes mainly via deflation. Despite the development of modern research tools and monitoring methods, the temporal and spatial changes in the intensity of soil degradation by aeolian processes in high latitude environments is still poorly understood. In this study, we sought to determine soil erosion rates, using anatomical features of Arctic shrubs and dwarf shrubs in northeastern Iceland, central Spitsbergen, and southern Greenland. The main research question we posed was: can the dendrochronological information contained in the anatomy of shrub roots be used to reconstruct soil degradation and erosion histories? We applied dendrochronological techniques to the exposed roots of dwarf willow (Salix herbacea L.), net-leaved willow (Salix reticulata L.), and common juniper (Juniperus communis L.), and estimated surficial erosion based on abrupt changes in cell size and width of annual growth increments in the roots. The accuracy of the dating of erosion processes was checked by comparison with dendrochronological reference scales from specimens collected from undisturbed site. We observed, that after exposure of shrub roots, cell size decreases by at least 50%, with the maximum changes in individual plants exceeding 150-200%. Based on this relationship, we estimated surficial erosion rates for Iceland (1970’s-present), as well as for Spitsbergen and Greenland (1980’s-present). We observed a rapid increase in erosion rates in the latter half of the 1990’s, approaching 5.4 – 6.1 cm/year. Our results confirmed the efficiency of the dendrochronological method we employed, for determining soil erosion rates, even in unforested areas. The method is particularly applicable to low-growing, Arctic dwarf shrubs, which develop measurable growth rings and cells, making them a reliable proxy in soil degradation studies.

The research was founded by a Polish National Science Centre project no. UMO-2021/41/B/ST10/03381 and project no. UMO-2019/35/D/ST10/03137.

How to cite: Owczarek, P., Opała-Owczarek, M., Dagsson-Waldhauserova, P., Schaetzl, R. J., and Migała, K.: Wind erosion rates in the Arctic as recorded the roots of tundra shrubs  – a new dendrochronological approach, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12880, https://doi.org/10.5194/egusphere-egu24-12880, 2024.

09:35–09:45
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EGU24-16439
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ECS
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On-site presentation
Helen Dulfer, Benjamin Boyes, Nico Dewald, Frances Butcher, Chris Clark, Jeremy Ely, and Anna Hughes

Under current climate conditions the Greenland and Antarctic sheets are rapidly losing mass and these losses are projected to accelerate into the future. Consequently, potential changes in the ice marginal environment across these ice sheets are a future concern. Palaeo-ice sheets, such as the Scandinavian Ice Sheet, provide an opportunity to investigate ice-marginal changes over longer timescales that span a variety of physiographic and geological settings and climate conditions. Landform signatures across Fennoscandia reveal a range of palaeo-ice marginal settings, including lake-terminating, marine-terminating, and higher-altitude environments. This makes the landform record of the Scandinavian Ice Sheet a rich and diverse archive for studying ice margin behaviour. Furthermore, high-resolution digital elevation models (DEMs) that exist for the former bed of this ice sheet allow us to examine ice marginal settings and dynamics in unprecedented and consistent detail across Norway, Sweden and Finland.

We present a geomorphological ice margin dataset of ~56,000 mapped features that categorises each ice margin by its dominant landform type of moraine, hummocky moraine, lateral meltwater channel or glaciofluvial sediment. We then use the morphology of the landforms and overprinting relationships to determine which landforms were likely formed prior to the last deglaciation. The distribution of landform-types in our dataset provides interesting insights into the behaviour of different sectors of the ice sheet. For example, we find ice margins characterised by lateral meltwater channels are almost exclusively found in locations of Quaternary sediment cover, which may indicate that surficial sediment thickness influences their formation, rather than the thermal regime of the ice. We also find ice margins defined by hummocky moraines are more prevalent at higher latitudes. We hypotheses this pattern may be controlled by lower ablation rates at higher latitudes. Additionally, we find contrasts in the density and size of the ice margins between the aquatic and land terminating environments, which results from differences in sedimentation processes within each environment.

How to cite: Dulfer, H., Boyes, B., Dewald, N., Butcher, F., Clark, C., Ely, J., and Hughes, A.: Contrasting regional ice margin dynamics of the Scandinavian Ice Sheet revealed by the landform record, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16439, https://doi.org/10.5194/egusphere-egu24-16439, 2024.

09:45–09:55
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EGU24-12797
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ECS
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On-site presentation
Greta Wells, Þorsteinn Sæmundsson, Finnur Pálsson, Eyjólfur Magnússon, Guðfinna Aðalgeirsdóttir, and Snævarr Guðmundsson

Arctic regions are warming at more than double the global average rate, causing significant changes in cryospheric and hydrologic patterns. As glaciers retreat, meltwater can accumulate in expanding proglacial lakes, which often form in overdeepened basins with large storage capacities and steep valley walls that are prone to paraglacial slope failures. If a mass movement event such as a rockfall or landslide enters the lake, the water can drain in a glacial outburst flood, significantly modifying the landscape. Moreover, many lakes are upstream of infrastructure, communities, and tourism sites, resulting in a high potential societal impact in the event of a flood. This process is a well-documented trigger of floods in glacial regions across the world, but it remains an emerging and understudied hazard in Iceland.

This study investigates past and future proglacial lake evolution and evaluates mass movement-triggered outburst flood risk at two sites in south Iceland. We present: 1) updated maps of lake bathymetry and subglacial topography derived from multibeam sonar and radio-echo sounding surveys, respectively; 2) past lake volume changes and projected future lake extent and volume; and 3) potential slope failure source areas and scenarios of mass movement-triggered outburst floods. These results lay the foundation for future work on flood modeling and hazard planning to mitigate impacts on communities and infrastructure. This project also serves as an excellent pilot study for this emerging hazard in Iceland and has significant potential for application to proglacial lakes in other Arctic and alpine regions.  

How to cite: Wells, G., Sæmundsson, Þ., Pálsson, F., Magnússon, E., Aðalgeirsdóttir, G., and Guðmundsson, S.: Future proglacial lake evolution and outburst flood hazards in south Iceland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12797, https://doi.org/10.5194/egusphere-egu24-12797, 2024.

09:55–10:05
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EGU24-17083
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On-site presentation
Neil Glasser, Matt Peacey, John Reynolds, Tom Holt, and Adam Hepburn

We investigate the influence of inherited glacier structures on the development of moraine dam morphology over 61 years on four glacial lake dams in the Eastern Himalaya. We compare glacier structures from 1962 Corona imagery with current dam features from 2023 Maxar imagery at Imja, West Barun, Melung and Dang Pu glaciers. From the Corona imagery, maximum glacier extents were identified, along with discrete flow units, ice cliffs, transverse structures, and supraglacial ponds at a 2.5 m resolution. In the Maxar imagery, key dam components were identified including extent of dead ice, hummocky moraines, thermokarst, and surface drainage features and surface structures, mapped at 1 m resolution. Our analysis revealed that former glacier flow unit boundary locations coincide with the development of hydrological features on the dam surface. This was augmented with further analysis of surface elevation change, thermokarst, and surface drainage development using historical aerial imagery, satellite imagery, and DEMs for Imja from 1962 to 2023. We propose that hydrological features exploit relict flow unit boundaries and conclude that inherited glacier structures are key in understanding the development of lake dams that contain dead ice. The glaciological influences on dam features should be included in integrated hazard assessments in glacial settings.

How to cite: Glasser, N., Peacey, M., Reynolds, J., Holt, T., and Hepburn, A.: Inherited glacier structures influence glacial lake dam morphology, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17083, https://doi.org/10.5194/egusphere-egu24-17083, 2024.

10:05–10:15
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EGU24-4926
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ECS
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Virtual presentation
Mohit Prajapati, Purushottam Kumar Garg, Sandipan Mukherjee, and Ajay Kumar Gupta

A glacial lake, characterized by its significant water volume, exists in association with a glacier (under, besides, and in front). They form due to glacial activities influenced by climatic variations. Glacial lakes generally impounded behind weak materials and can rupture suddenly due to various triggers, resulting to catastrophic floods known as Glacial Lake Outburst Floods (GLOFs). Lake’s topography particularity plays a crucial role in its formation and sustenance. Glacial lake related hazards are increasingly gaining attention due to their potential for causing significant damage and loss of life and property in high mountain regions worldwide. Therefore, it is imperative to regularly map and analyze various lake characteristics to understand any potential hazards originating from them.  Considering this, current study aims to present a comprehensive and updated inventory of glacial and high-altitude lakes in the Kargil district of Ladakh and systematically analyzes their types and topographic attributes. With the analysis of recent Sentinel-2 MSI imagery (2022), we identified a total of 355 glacier and high-altitude lakes in the Kargil district, encompassing an area of 4.8 ± 1.2 km2. These lakes are divided into four classes mainly based on their relationship with the glaciers: proglacial lakes away from the glacier (PGLA), proglacial lake in contact with glacier (PGLC), supraglacial lakes (SGL) and other lakes (OL). Results reveal that though PGLCs are comparatively low in number (85) but they occupy the largest area share of 60% in total glacial lakes covering an area of 2.88 ± 0.7 km2. PGLAs are 138 in number and occupy the second largest area of 0.9 ± 0.2 km2. There are large number (103) of SGLs with an area coverage of 0.32 ± 0.07 km2. OLs are limited in number (29) and cover 0.6 ± 0.1 km2 of area.  The lake sizes range from 0.001 km2 to 0.579 km2 with an average lake area of 0.013 km2 indicating that the lakes in the region are small in size and are in their initial phase of development. The mean elevation for the lakes is 4605 m and notably, ~21% of them predominantly oriented in a southward direction. The majority of lakes are situated on slopes with a gradient ranging 2-8° which reflects their potential to grow in size. It can be deduced from the analysis that the glaciated areas in Kargil region is dominated by large number of PGLC and PGLAs which are likely expand in future posing serious threat to the communities living in immediate proximities to the glaciers. Overall, this research contributes to our understanding of glacier lakes in the Kargil district of the Ladakh region, providing essential data for informed decision-making in order to minimize the glacial lake related hazards.

Keywords: Glacial lake inventory; High altitude lakes; Ladakh Himalaya; Remote sensing; Glacier Lake hazards.

How to cite: Prajapati, M., Garg, P. K., Mukherjee, S., and Gupta, A. K.: Inventory and topographic analysis of glacial and high-altitude lakes in Kargil district, Union Territory of Ladakh, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4926, https://doi.org/10.5194/egusphere-egu24-4926, 2024.

Posters on site: Wed, 17 Apr, 10:45–12:30 | Hall X3

Display time: Wed, 17 Apr 08:30–Wed, 17 Apr 12:30
Chairpersons: Sven Lukas, Clare Boston, Jenna Sutherland
X3.99
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EGU24-12138
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ECS
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Highlight
Jonas Eschenfelder, Cansu Culha, Shawn Chartrand, and Mark Jellinek

Polygonal patterned ground (polygons) is ubiquitous in polar periglacial regions. It is thought to form due to repeated fracturing of the ground during freeze-thaw as a result of fluctuations in air temperature and soil conditions. Polygons can channelise overland flow in their troughs and guide groundwater flow during permafrost thaw, providing pathways for channel network development. Given the importance of polygons on local hydrology and geomorphology in cold regions, a key knowledge gap exists: We do not yet understand the evolution of existing polygons or the formation of new polygons under a changing climate. This is especially important as climate change is causing cold region water budgets to change, driving landscape change.

We investigate the morphologic characteristics that are associated with polygons to indirectly examine their formation mechanism. We extensively map polygon morphologies across the McMurdo Dry Valleys in Antarctica, Prudhoe Bay in Alaska, as well as on Devon Island and Axel-Heiberg Island in the Canadian High Arctic using high-resolution DEMs derived from LiDAR data. We use a semi-automatic mapping tool based on adaptive thresholding to accelerate and scale our efforts while also improving reproducibility. We calculate surface slope and roughness for baseline lengths of 3m to 300m to investigate how and whether polygon morphology varies with local and regional topography.

Overall, we quantify how polygon shape and form varies by proximity to important hydrological features. For example, in the McMurdo Dry Valleys, polygons are more often orthogonal and low-centred when they are closer to streams and glacier termini, but are characteristically hexagonal and high-centred  elsewhere. Orthogonal polygons are characterised by a smoother surface compared to hexagonal polygons across all baseline lengths, bounded by a rough `ridge’ on one side and a stream on the other. Further, on Axel-Heiberg, polygons that formed within the last 60 years are more orthogonal the closer they are to a lake. These observations suggest that polygon shape is controlled by soil moisture. 

It is commonly accepted that polygons form as a result of thermal contraction cracking followed by ice- or sand-wedge formation, and field studies suggest that the formation of ice-wedges over sand-wedges can be explained by elevated soil or air moisture. Sand-wedges potentially are more deformable than ice-wedges, allowing for the fracture network to evolve and relax into a hexagonal pattern, whereas ice-wedges would preserve the initial, orthogonal, pattern. Consequently, we hypothesise that the number and size of ice-wedges decreases along soil moisture gradients, and hence polygons farther away from water sources evolve into hexagonal shapes over repeated fracture cycles. This would mean that existing streams and other water sources set up gradients in the amount of ice stored throughout a polygon field, which in turn will influence both surface and groundwater flow during permafrost thaw, pointing towards complex interactions between polygons and landscape evolution in a changing climate.

How to cite: Eschenfelder, J., Culha, C., Chartrand, S., and Jellinek, M.: Morphological comparison of polygonal patterned ground across the Arctic and Antarctic: Implications for polygon formation on Earth and Mars, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12138, https://doi.org/10.5194/egusphere-egu24-12138, 2024.

X3.100
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EGU24-5293
Luca Carturan, Giulia Zuecco, Jacopo Boaga, Costanza Morino, Mirko Pavoni, Roberto Seppi, Monica Tolotti, Thomas Zanoner, and Matteo Zumiani

In alpine areas, spring-water temperature is affected by the presence of permafrost and by changes in the periglacial domain caused by the current atmospheric warming. Our interest in spring-water temperature is related to the possibility of investigating the spatial distribution of alpine permafrost and its changes. In particular, spring-water temperature might be helpful as indicator of permafrost occurrence in areas where it is discontinuous or sporadic, and in general where its distribution is poorly known.

The spring-water temperature in late summer is a useful evidence of permafrost, and various authors employed such method as auxiliary permafrost evidence, or as a stand-alone method that can be used for mapping permafrost distribution at the catchment scale. However, little is known on the spatial and temporal variability of water temperature at springs with different permafrost contribution and characteristics.

Here we present an analysis of the spatial and temporal variability of spring-water temperature in a 795 km2 catchment located in the Eastern Italian Alps, aimed at investigating the spatial distribution of permafrost and its effect on spring-water temperature. From 2018 to 2021, we measured the late-summer spring-water temperature at 220 springs, 133 of which are located downslope of rock glaciers, 81 downslope of other deposits, and 8 in bedrock. In addition, we installed dataloggers for continuous temperature measurements at 31 springs.

Results show that the cold springs are mainly associated with intact rock glaciers but also with rock glaciers classified as relict, especially if they have blocky and sparsely vegetated surface. Accordingly, the latter should be reclassified as pseudo-relict, i.e. they appear to be visually relict but host patchy permafrost, as confirmed by geophysics carried out at selected case studies. These results have important implications for the study and modelling of the hydrological, hydrochemical and ecological response of periglacial environments under ongoing climate change.

How to cite: Carturan, L., Zuecco, G., Boaga, J., Morino, C., Pavoni, M., Seppi, R., Tolotti, M., Zanoner, T., and Zumiani, M.: Thermal characteristics of springs fed by mountain permafrost in Val di Sole (Eastern Italian Alps), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5293, https://doi.org/10.5194/egusphere-egu24-5293, 2024.

X3.101
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EGU24-20546
Christian Bauer, Andreas Kellerer-Pirklbauer, and Thomas Wagner

The formation of dolines (or sinkholes) lasts commonly for long periods of time exceeding 10 ka or even 100 ka. Climatic conditions over such long timescales might vary substantially and thus dolines in nowadays temperate climatic conditions were substantially shaped during markedly different climates, namely the colder conditions which dominated during the Pleistocene. In this contribution we focus on a specific form of dolines which are located at the eastern boundary of the European Alps in the so-called Central Styrian Karst (CSK) where periglacial conditions dominated during the colder periods of the Pleistocene. The CSK comprises the occurrence of karst formations in carbonate rocks near Graz, Austria. Unlike in alpine regions further west, this area remained unaffected by Pleistocene glacial erosion and was never glaciated. Given the absence of glacial erosion and the dominance of subaerial processes, (karst-) morphological features are assumed to exist since a long period of time. Consequently, the CSK is a prominent area to investigate landscape evolution in a non-glaciated Alpine area where karstifiable rock were also affected by periglacial processes during the colder periods of the Pleistocene. In addition, the landscape comprises numerous planation surfaces grouped into several levels dating to several Mio. yrs BP. Previously unknown for the CSK are the asymmetries of many dolines detected recently due to airborne laser scanning data. These dolines exhibit a NW-SE elongation, with steeper slopes facing S-to-SE, and flatter ones facing N-to-NW. Some authors have attributed asymmetric dolines in other regions to tectonic influences. However, dolines in close proximity to main fault systems in the CSK do not display these peculiar asymmetries. In addition, dolines further away from the main fault systems show obvious asymmetries. The detected asymmetries of dolines occur at various levels ranging from 540 to 780 m a.s.l. indicating possibly different ages of formation. This contradicts a syngenetic origin of elongation and suggests subsequent re-shaping after primary formation of dolines. Similar asymmetries observed in the Northern Calcareous Alps further to the north have been interpreted as the result of snow-patches, where prevailing wind directions cause snow accumulation in the lee side of doline rims. This type of karst is known as nival karst, which requires the absence of glacial erosion and permafrost to impede subsurface drainage. The CSK satisfies the climatic conditions for the development of nival karst during colder periods of the Pleistocene as judged from past periglacial climate estimations for this area. We hypothesize that the morphometry and formation of asymmetric dolines in the CSK must be seen in relation to a severe periglacial influence and are thus a legacy of (severe/long-term?) periglacial conditions of the past.

How to cite: Bauer, C., Kellerer-Pirklbauer, A., and Wagner, T.: Is the asymmetry of dolines in the Central Styrian Karst determined by periglacial processes? , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20546, https://doi.org/10.5194/egusphere-egu24-20546, 2024.

X3.102
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EGU24-9888
Andreas Kellerer-Pirklbauer, Isabelle Gärtner-Roer, Xavier Bodin, and Luca Paro

Periglacial landforms are widespread features in the European Alps, which cover an area of 190,900 km². The mountain range is arcuated in the western part, extend over a length of 1200 km, are up to 280 km wide, and reach their highest elevation at Mont Blanc (4807.8 m a.s.l.) at the French/Italian border. About 19% of the Alps exceed 2000 m and some 52% of the area consists of carbonate rocks at the surface, which is relevant for karstification processes. During the Last Glacial Maximum some 20 ka ago, 55% of the Alps were covered by glaciers whereas the remaining area was impacted by moderate to severe periglacial conditions causing the formation of widespread periglacial landforms still visible today, particularly at the Alpine margin. During the following Late Glacial period terminating with the Younger Dryas period about 11.7 ka ago, previously glaciated areas were reshaped by periglacial processes forming for instance complex rock glacier systems and solifluction landforms which characterize many high-elevated regions in the Alps until today. Nowadays, active periglacial processes are restricted to elevations above 2000 m in the marginal areas and above 2400 m at the central parts of the Alps. Around 11% of the European Alps are in this active periglacial belt, constrained by the potential treeline as the lower limit and the currently glaciated areas (1% of the Alps) as the upper limit. The widespread existence of relict and active periglacial landforms in the Alps inspired research by many scholars and scientists since centuries. Even Leonardo da Vinci made some periglacial-related observations in the late 15th century. Despite this long traditions and comprehensive experiences in periglacial landform research, future periglacial research is still needed and will help to better understand the impact of ongoing climate change on the periglacial reshaping of this remarkable mountain chain. In this contribution we will present a summary of a recently published book chapter dedicated to the European Alps (Kellerer-Pirklbauer et al. 2022), which is part of a book dealing with the periglacial landscapes of Europe (Oliva et al. 2022).

References:

Kellerer-Pirklbauer A, Gärtner-Roer I, Bodin X, Paro L (2022) European Alps. In: Oliva M, Nyvlt D, Fernández-Fernández JM (eds), Periglacial landscapes of Europe. Springer, Cham. 147-224. https://doi.org/10.1007/978-3-031-14895-8_9

Oliva M, Nyvlt D, Fernández-Fernández JM (eds) (2022) Periglacial landscapes of Europe. Springer, Cham. 523 pp. https://doi.org/10.1007/978-3-031-14895-8

How to cite: Kellerer-Pirklbauer, A., Gärtner-Roer, I., Bodin, X., and Paro, L.: Periglacial processes and landforms in the European Alps: From the Last Glacial Maximum via Leonardo da Vinci to the present, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9888, https://doi.org/10.5194/egusphere-egu24-9888, 2024.

X3.103
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EGU24-9425
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ECS
Eva Gautsch and Andreas Kellerer-Pirklbauer

The Schmidt-hammer (SH) is a well-established method in studying glacial and periglacial landforms in alpine regions. Schmidt-hammer rebound values (or R-values) allow the relative-age dating of landforms by quantifying the degree of weathering and therefore length of surface exposure. R-values are controlled by lithological variations impacting weathering rates. SH sampling in a specific study should therefore focus on one lithology. Earlier studies found out that some rock types are less suitable than others because of their specific weathering rind development over time. Some rock types are even unsuitable for the application of the SH. In the past, conglomerates for instance were rarely used for SH measurements, which may be related to problems in SH discrimination between the matrix and the clasts of conglomerates. In this study, we applied the SH method at several relict rock glacier systems and lateral moraine ridges which consist of conglomerate and sandstone material of Upper Carboniferous age. The landforms studied are in two cirques (Rosaninalm, Hinteralm; 46.9°N, 13.8°E) in the Gurktal Alps, Austria. We accomplished SH sampling at altogether 21 sites with 100 individual SH measurements per site. The 21 SH measurement sites are located along five longitudinal profiles that were placed over the different landscape forms, the longest one over a horizontal distance of 1.3 km. Measurements focussed on the matrix material of the conglomerates. Mean R-values vary between 29.6 and 39.0. Using these results and assuming a reasonable mean decrease in R-value of 1.5 per ka (based on nearby data from gneiss material), one can assume that the landforms studied were formed over a total period of approximately 6000 years. Individual landform units, in our case mostly rock glaciers, seem to have formed over periods of between 1.1 and 4.9 ka. By using these age estimates and present permafrost conditions, the onset of moraine and rock glacier formation was presumably during the Oldest Dryas and landform stabilisation occurred during the early Holocene. Several uncertainties remain, however, which will be addressed at the poster.

How to cite: Gautsch, E. and Kellerer-Pirklbauer, A.: Feasible task? The application of the Schmidt-hammer method for dating rock glaciers made of conglomerate rock, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9425, https://doi.org/10.5194/egusphere-egu24-9425, 2024.

X3.104
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EGU24-3918
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ECS
Elizabeth Orr and Rachel Oien

In recent years, increased theoretical and modelling-based research has explored the persistence of mountain topography and the processes and timescales over which landscapes achieve a stable or ‘steady state’ form. Across various sub-disciplines of geomorphology, amphitheatre or arm-chair-shaped topography has been recognised as a more persistent landscape form, attainable through glacial, periglacial and/or fluvial processes. Once achieved, rates of landscape change may be subdued, or a higher magnitude forcing or event is needed to significantly alter the form. This has yet to be empirically tested in the headwaters of mountain catchments.

This study evaluates the extent to which the morphometrics of catchment headwaters can provide insight into the persistence of mountain landscapes. This is achieved by exploring the dynamic relationships between topographic form and erosion in the Swiss Alps and Blue Ridge Mountains, USA.  We focus on two distinct mountain regions to capture a range of tectonic, climatic, and glacial settings. We use the novel ACME 2.0 GIS tool and high-resolution LiDAR data to characterise the morphometrics (inc. circularity, relief, hilltop curvature, hillslope length) of more than 50 catchments. We introduce a new Headwaters Topographic Form Index (HTFI) derived from these data, which allows us to compare topographic form between diverse mountain environments. To explore the links between form and rates of landscape change, we compare the HTFI and morphometric data with published catchment-averaged erosion rates.

This study aims to explore some of the factors influencing landscape persistence in mountain catchment headwaters, providing new insights into how vulnerable mountain landscapes may respond to ongoing and future climate change. This work has implications for research focused on hillslope stability, mountain hazards (e.g., landsliding), and landscape evolution modelling.

How to cite: Orr, E. and Oien, R.: Exploring landscape persistence and erosion dynamics in mountain catchments: A morphometric approach in the Swiss Alps and Blue Ridge Mountains, USA, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3918, https://doi.org/10.5194/egusphere-egu24-3918, 2024.

X3.105
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EGU24-8710
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ECS
Paulina Mejías Osorio, Daniel Le Heron, Ricarda Wohlschlägl, Bethan Davies, and Bernhard Grasemann

Glacial forefields host a wide array of processes and landforms, which can vary significantly, even within today’s overarching context of rapid melting and recession correlated to anthropogenic climate forcing. Detailed studies of the geomorphology and sedimentology of glacial forefields provide insight regarding sediment transport, meltwater pathways, and the behavior of the ice itself. Patagonia’s glaciers have been inventoried, there is vast knowledge of paleoglacier extent, and remote sensing has focused mainly on calculating geometrical changes and velocities. By comparison, detailed sedimentological analyses are long overdue and landsystems models for the present-day state of these environments require updating. This work focuses on the sedimentary processes that are occurring at modern glacial margins, specifically at selected sites in the Northern Patagonian Icefield and the neighboring Monte San Lorenzo massif to the east. High resolution geomorphological maps generated with photogrammetric data from an uncrewed aerial vehicle are presented. These maps, complimented with sedimentological facies descriptions and stratigraphic logging seek to characterize landsystems for the margins of glaciers in and near the Northern Patagonian Icefield, thus working towards an accurate reading of the sedimentary record and a better understanding of current glacial processes.

How to cite: Mejías Osorio, P., Le Heron, D., Wohlschlägl, R., Davies, B., and Grasemann, B.: Exploring the modern-day sedimentary record of glacial margins in central Chilean Patagonia , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8710, https://doi.org/10.5194/egusphere-egu24-8710, 2024.

X3.106
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EGU24-7745
Danni Pearce, William Harcourt, Wojciech Gajek, Richard Hann, Brice Rea, Douglas Benn, Sven Lukas, Harold Lovell, and Matteo Spagnolo

The sedimentary processes taking place beneath contemporary surging glaciers are difficult to observe directly, yet they are crucial for building a holistic understanding of glacier surge processes and mechanisms. Settings where the sediment-landform assemblages characterising the ice-bed interface are preserved without significant modification are therefore an important archive of the subglacial processes that are active during a surge. At tidewater surging glaciers, landforms are often excellently preserved in a submarine setting, but analysis of these beyond mapping from high-resolution bathymetry data (where available) can be limited. However, in most cases, there are also subaerially exposed sediments and landforms at the terrestrial fjord margins, providing an accessible and rich source of data of the subglacial environment of a surging glacier.

Borebreen is a tidewater glacier on the northwestern side of Isfjorden in Svalbard. Previously published detailed bathymetric data has identified a suit of submarine glacial landforms formed during the last surge of Borebreen ~100 years ago. The subsequent quiescent phase has exposed a wide spread of crevasse-squeeze ridges (CSRs) both in the fjord and on the terrestrial margins. These are important landforms that are unique to surging glaciers and can therefore provide information concerning surge dynamics and subglacial processes. We present initial geomorphological and geotechnical data from the CSRs through mapping and direct measurements using a hand-held shear vane test, pocket penetrometer and particle size analysis. High-resolution orthmosaics and Digital Elevation Models (DEMs) from drone surveys of the proglacial foreland were collected in order to assess the spatial pattern of CSRs and a Python-based ArcGIS toolbox was used to automatically extract 3D morphometric data from the DEMs. These data provide an opportunity to investigate the links between the sediment geotechnical properties, CSR geometries and surge processes and mechanisms; such as the identification of spatial patterns in the state of sediment consolidation within CSRs and CSR morphometrics.

How to cite: Pearce, D., Harcourt, W., Gajek, W., Hann, R., Rea, B., Benn, D., Lukas, S., Lovell, H., and Spagnolo, M.: Investigating the signature of a tidewater glacier surge behaviour using geomorphological, sedimentological and geotechnical data: Borebreen, Svalbard. , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7745, https://doi.org/10.5194/egusphere-egu24-7745, 2024.

X3.107
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EGU24-11992
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Highlight
Timothy Lane, Christopher Darvill, Brice Rea, Mike Bentley, James Smith, Stewart Jamieson, Colm Ó Cofaigh, and David Roberts

Understanding ice stream dynamics over decadal to millennial timescales is crucial for improving numerical model projections of ice sheet behaviour and future ice loss. Here, we document the terrestrial deglacial landsystem of Nioghalvfjerdsfjorden Glacier (79N) in Northeast Greenland following the Last Glacial Maximum, and the lateral transition of that margin to a floating ice shelf. High-elevation areas are influenced by local ice caps and display autochthonous to allochthonous blockfields that mark the interaction of local ice caps with the ice stream below. Below ~600 m a.s.l. glacially abraded bedrock surfaces and assemblages of lateral moraines, ‘hummocky’ moraine, fluted terrain, and ice-contact deltas record the former presence of warm-based ice and thinning of the grounded ice stream margin through time. In the outer fjord a range of landforms such as ice shelf moraines, dead-ice topography, and weakly developed ice marginal glaciofluvial outwash was produced by an ice shelf during deglaciation. Along the mid- and inner-fjord areas this ice shelf signal is absent, suggesting ice shelf disintegration prior to grounding line retreat under tidewater conditions. However, below the marine limit, the geomorphological record along the fjord indicates the expansion of the 79N ice shelf during the Neoglacial, which culminated in the Little Ice Age. This has been followed by 20th Century recession, with the development of a suite of compressional ice shelf moraines, ice-marginal fluvioglacial corridors, kame terraces, dead-ice terrain, and crevasse infill ridges. These mark rapid ice shelf thinning and typify the present-day ice shelf landsystem in a warming climate.

How to cite: Lane, T., Darvill, C., Rea, B., Bentley, M., Smith, J., Jamieson, S., Ó Cofaigh, C., and Roberts, D.: Geomorphological record of a former ice stream to ice shelf lateral transition zone in Northeast Greenland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11992, https://doi.org/10.5194/egusphere-egu24-11992, 2024.

X3.108
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EGU24-14648
Joohee Jo, Dohyeong Kim, Seungyeon Sohn, Seolhui Bang, Maria Ansine Jensen, Seung-il Nam, and Kyungsik Choi

Global warming after the Little Ice Age (LIA) has triggered rapid glacier retreat in an arctic coastal region, instigating substantial environmental changes in the fluvial-marine transition zone (FMTZ). A comprehensive understanding of the sedimentary environments affected by glaciofluvial, tidal, and wave processes is imperative for predicting the ongoing impacts of global warming. Despite logistical challenges and limited accessibility, we investigate the influence of glacier melting on the evolution of depositional environments in the Arctic FMTZ, focusing on the deglaciated Dicksonfjorden in Svalbard. Our study involves the collection of undisturbed cores from glaciofluvial rivers, tidal channels, and spits to elucidate the spatial distribution of sedimentary facies. Hydrodynamic observations in tidal channels enable to comprehend sediment transport dynamics. The glaciofluvial river which is nourished by high-turbid snowmelt waters forms braided channels that intricately dissect extensive tidal flats in the downfjord. Sedimentary facies reflect an increasing tidal influence, transitioning from downstream-directed climbing-rippled sands to interlaminated sands and muds towards the sea. Tidal point bars exhibit inclined heterolithic stratification, comprising bidirectional rippled silts and interlaminated silts. Gravelly beds on the spits incline towards the shore, primarily attributed to wave-induced cliff erosion. The microtidal regime, characterized by ebb tidal asymmetry, experiences peaks in suspended sediment concentration during ebb tides. Estimated sedimentation rates calculated from 210-Pb activities averaged 0.14 cm/year from the 1920s to 2020. Notably, the rate has increased from 0.07 cm/year (1980s-2000) to 0.23 cm/year (2000-2020). This study underscores the profound impact of accelerated climate warming on increased meltwater and sediment discharges post-LIA, driving active delta progradation and instigating morphological changes in deglaciated arctic coastal environments.

How to cite: Jo, J., Kim, D., Sohn, S., Bang, S., Jensen, M. A., Nam, S., and Choi, K.: Depositional environments in the fjord head delta of deglaciated Dicksonfjorden, Svalbard: The impact of global warming after the post-little ice age, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14648, https://doi.org/10.5194/egusphere-egu24-14648, 2024.

X3.109
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EGU24-14909
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ECS
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Jinhao Xu, Min Feng, and Yijie Sui

Moraine-dammed glacial lakes are naturally formed by the accumulation of moraine debris in high mountain glacier environments. Due to their remote locations and the challenges in identification, these lakes often elude systematic and comprehensive surveys. However, under the influences of glacier melting and climate change, they can potentially cause catastrophic outburst floods, threatening the safety of downstream communities and the stability of ecosystems. Therefore, precise identification and monitoring of these lakes are crucial for disaster early warning and risk management.

The aim of this study is to develop a novel method based on multi-source remote sensing data and Vision Transformer technology for effectively identifying moraine-dammed glacial lakes. Traditional remote sensing methods face numerous challenges in these high mountain environments, such as confusion with similar water bodies and the impact of complex terrain. Our proposed method focuses on utilizing moraine accumulation characteristics, a key factor in the formation of moraine-dammed lakes. By analyzing the relationship between glacier movement and lake formation, we aim to more accurately identify potential dammed lakes, thereby reducing misidentifications.

We are using high-resolution satellite imagery and terrain data, combined with the Vision Transformer model for feature extraction. This model is capable of efficiently processing a large amount of complex spatial data and identifying specific geographical and geomorphological features. We are focusing on changes at the glacier front and terrain changes related to lake formation. Through this approach, we aim to extract key features directly related to the formation of moraine-dammed glacial lakes, thus improving the accuracy of identification.

Additionally, we are establishing a database containing samples of known moraine-dammed glacial lakes to train and validate our model. By comparing it with existing databases of moraine-dammed glacial lakes, we aim to further test the effectiveness and reliability of our method. We are anticipating that this research will provide a new technological approach for monitoring moraine-dammed glacial lakes, with significant scientific importance and practical value in understanding the mechanisms of lake formation, assessing potential risks, and developing effective disaster prevention measures.

How to cite: Xu, J., Feng, M., and Sui, Y.: Identifying Moraine-Dammed Glacial Lakes Using Moraine Accumulation Characteristics and Vision Transformer , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14909, https://doi.org/10.5194/egusphere-egu24-14909, 2024.

X3.110
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EGU24-17442
Louise Callard, Sebastian Pitman, Devin Harrison, Neil McDonald, Matthew Perks, Rupert Bainbridge, Matthew Roberts, Jenny Snell, and Andrew Russell

Since the turn of the 21st century the appearance and expansion of the most recent proglacial lakes fronting Skeiðarárjökull in SE Iceland, has led to the sandur being disconnected or decoupled from the glacier. Consequently, the sediment that would otherwise be deposited on the sandur is instead trapped within these lakes, leading to sediment deprivation of the distal sandar which in-turn impacts the fluvial and coastal systems. The recent formation of proglacial lakes also provides new challenges for jökulhlaup hazard assessment. Despite their importance, there have been no detailed studies of this large-scale proglacial sedimentary systems undergoing active decoupling, and the role of this process for sediment flux and landscape development remains unclear. In December 2021, Grimsvötn subglacial lake drained 0.9 km3 of water as a jökulhlaup from Skeiðarárjökull. A comprehensive survey of the proglacial lakes (sub-bottom profiling and single beam echosounder) and proximal sandur system (ground penetrating radar (GPR) and UAS survey), along with the collection of sediment cores, was conducted after the event. This provides a rare opportunity to capture the geomorphological and sedimentary signature of a jökulhlaup within a subaqueous setting and the downstream fluvial system. We present a model of the controls on jökulhlaup impact on landform and sedimentary assemblages within the proglacial lakes and connected glacifluvial system of Skeiðarársandur. This provides a modern analogue for Quaternary glacier and ice sheet margins.

How to cite: Callard, L., Pitman, S., Harrison, D., McDonald, N., Perks, M., Bainbridge, R., Roberts, M., Snell, J., and Russell, A.: December 2021 Jökulhlaup impact on landform and sedimentary assemblages on the decoupled Skeiðarársandur system, SE Iceland: implications for the Quaternary record., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17442, https://doi.org/10.5194/egusphere-egu24-17442, 2024.