Articles | Volume 14, issue 6
https://doi.org/10.5194/tc-14-1989-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/tc-14-1989-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
A quasi-annual record of time-transgressive esker formation: implications for ice-sheet reconstruction and subglacial hydrology
Stephen J. Livingstone
CORRESPONDING AUTHOR
Department of Geography, University of Sheffield, Sheffield, UK
Emma L. M. Lewington
Department of Geography, University of Sheffield, Sheffield, UK
Chris D. Clark
Department of Geography, University of Sheffield, Sheffield, UK
Robert D. Storrar
Department of the Natural and Built Environment, Sheffield Hallam
University, Sheffield, UK
Andrew J. Sole
Department of Geography, University of Sheffield, Sheffield, UK
Isabelle McMartin
Geological Survey of Canada, Natural Resources Canada, Ottawa, ON, Canada
Nico Dewald
Department of Geography, University of Sheffield, Sheffield, UK
Department of Geography, University of Sheffield, Sheffield, UK
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Izabela Szuman, Jakub Z. Kalita, Christiaan R. Diemont, Stephen J. Livingstone, Chris D. Clark, and Martin Margold
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A Baltic-wide glacial landform-based map is presented, filling in a geographical gap in the record that has been speculated about by palaeoglaciologists for over a century. Here we used newly available bathymetric data and provide landform evidence of corridors of fast ice flow that we interpret as ice streams. Where previous ice-sheet-scale investigations inferred a single ice source, our mapping identifies flow and ice margin geometries from both Swedish and Bothnian sources.
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We used the new-generation ICESat-2 altimeter to detect and monitor active subglacial lakes in unprecedented spatiotemporal detail. We created a new inventory of 18 active subglacial lakes as well as their elevation and volume changes during 2019–2020, which provides an improved understanding of how the Greenland subglacial water system operates and how these lakes are fed by water from the ice surface.
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Lakes form on the surface of the Antarctic Ice Sheet during the summer. These lakes can generate further melt, break up floating ice shelves and alter ice dynamics. Here, we describe a new automated method for mapping surface lakes and apply our technique to the Amery Ice Shelf between 2005 and 2020. Lake area is highly variable between years, driven by large-scale climate patterns. This technique will help us understand the role of Antarctic surface lakes in our warming world.
Izabela Szuman, Jakub Z. Kalita, Marek W. Ewertowski, Chris D. Clark, Stephen J. Livingstone, and Leszek Kasprzak
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The Baltic Ice Stream Complex was the most prominent ice stream of the last Scandinavian Ice Sheet, controlling ice sheet drainage and collapse. Our mapping effort, based on a lidar DEM, resulted in a dataset containing 5461 landforms over an area of 65 000 km2, which allows for reconstruction of the last Scandinavian Ice Sheet extent and dynamics from the Middle Weichselian ice sheet advance, 50–30 ka, through the Last Glacial Maximum, 25–21 ka, and Young Baltic advances, 18–15 ka.
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The Cryosphere, 14, 2949–2976, https://doi.org/10.5194/tc-14-2949-2020, https://doi.org/10.5194/tc-14-2949-2020, 2020
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We map visible traces of subglacial meltwater flow across Keewatin, Canada. Eskers are commonly observed to form within meltwater corridors up to a few kilometres wide, and we interpret different traces to have formed as part of the same integrated drainage system. In our proposed model, we suggest that eskers record the imprint of a central conduit while meltwater corridors represent the interaction with the surrounding distributed drainage system.
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The retreat of the northwestern Laurentide Ice Sheet allows us to investigate how the ice drainage network evolves over millennial timescales and understand the influence of climate forcing, glacial lakes, and the underlying geology on the rate of deglaciation. We reconstruct the changes in ice flow at 500-year intervals and identify rapid reorganisations of the drainage network, including variations in ice streaming that we link to climatically-driven changes in the ice sheet surface slope.
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We map and quantify surface rivers and lakes at Humboldt Glacier to examine seasonal evolution and provide new insights of network configuration and behaviour. A widespread supraglacial drainage network exists, expanding up the glacier as seasonal runoff increases. Large interannual variability affects the areal extent of this network, controlled by high- vs. low-melt years, with late summer network persistence likely preconditioning the surface for earlier drainage activity the following year.
Felix S. L. Ng
The Cryosphere, 17, 3063–3082, https://doi.org/10.5194/tc-17-3063-2023, https://doi.org/10.5194/tc-17-3063-2023, 2023
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The stable isotopes of oxygen and hydrogen in ice cores are routinely analysed for the climate signals which they carry. It has long been known that the system of water veins in ice facilitates isotopic diffusion. Here, mathematical modelling shows that water flow in the veins strongly accelerates the diffusion and the decay of climate signals. The process hampers methods using the variations in signal decay with depth to reconstruct past climatic temperature.
Yubin Fan, Chang-Qing Ke, Xiaoyi Shen, Yao Xiao, Stephen J. Livingstone, and Andrew J. Sole
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We used the new-generation ICESat-2 altimeter to detect and monitor active subglacial lakes in unprecedented spatiotemporal detail. We created a new inventory of 18 active subglacial lakes as well as their elevation and volume changes during 2019–2020, which provides an improved understanding of how the Greenland subglacial water system operates and how these lakes are fed by water from the ice surface.
Sophie Goliber, Taryn Black, Ginny Catania, James M. Lea, Helene Olsen, Daniel Cheng, Suzanne Bevan, Anders Bjørk, Charlie Bunce, Stephen Brough, J. Rachel Carr, Tom Cowton, Alex Gardner, Dominik Fahrner, Emily Hill, Ian Joughin, Niels J. Korsgaard, Adrian Luckman, Twila Moon, Tavi Murray, Andrew Sole, Michael Wood, and Enze Zhang
The Cryosphere, 16, 3215–3233, https://doi.org/10.5194/tc-16-3215-2022, https://doi.org/10.5194/tc-16-3215-2022, 2022
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Terminus traces have been used to understand how Greenland's glaciers have changed over time; however, manual digitization is time-intensive, and a lack of coordination leads to duplication of efforts. We have compiled a dataset of over 39 000 terminus traces for 278 glaciers for scientific and machine learning applications. We also provide an overview of an updated version of the Google Earth Engine Digitization Tool (GEEDiT), which has been developed specifically for the Greenland Ice Sheet.
Camilla M. Rootes and Christopher D. Clark
E&G Quaternary Sci. J., 71, 111–122, https://doi.org/10.5194/egqsj-71-111-2022, https://doi.org/10.5194/egqsj-71-111-2022, 2022
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Glacial trimlines are visible breaks in vegetation or landforms that mark the former extent of glaciers. They are often observed as faint lines running across valley sides and are useful for mapping the three-dimensional shape of former glaciers or for assessing by how much present-day glaciers have thinned and retreated. Here we present the first application of a new trimline classification scheme to a case study location in central western Spitsbergen, Svalbard.
Benjamin Joseph Davison, Tom Cowton, Andrew Sole, Finlo Cottier, and Pete Nienow
The Cryosphere, 16, 1181–1196, https://doi.org/10.5194/tc-16-1181-2022, https://doi.org/10.5194/tc-16-1181-2022, 2022
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The ocean is an important driver of Greenland glacier retreat. Icebergs influence ocean temperature in the vicinity of glaciers, which will affect glacier retreat rates, but the effect of icebergs on water temperature is poorly understood. In this study, we use a model to show that icebergs cause large changes to water properties next to Greenland's glaciers, which could influence ocean-driven glacier retreat around Greenland.
Peter A. Tuckett, Jeremy C. Ely, Andrew J. Sole, James M. Lea, Stephen J. Livingstone, Julie M. Jones, and J. Melchior van Wessem
The Cryosphere, 15, 5785–5804, https://doi.org/10.5194/tc-15-5785-2021, https://doi.org/10.5194/tc-15-5785-2021, 2021
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Lakes form on the surface of the Antarctic Ice Sheet during the summer. These lakes can generate further melt, break up floating ice shelves and alter ice dynamics. Here, we describe a new automated method for mapping surface lakes and apply our technique to the Amery Ice Shelf between 2005 and 2020. Lake area is highly variable between years, driven by large-scale climate patterns. This technique will help us understand the role of Antarctic surface lakes in our warming world.
Izabela Szuman, Jakub Z. Kalita, Marek W. Ewertowski, Chris D. Clark, Stephen J. Livingstone, and Leszek Kasprzak
Earth Syst. Sci. Data, 13, 4635–4651, https://doi.org/10.5194/essd-13-4635-2021, https://doi.org/10.5194/essd-13-4635-2021, 2021
Short summary
Short summary
The Baltic Ice Stream Complex was the most prominent ice stream of the last Scandinavian Ice Sheet, controlling ice sheet drainage and collapse. Our mapping effort, based on a lidar DEM, resulted in a dataset containing 5461 landforms over an area of 65 000 km2, which allows for reconstruction of the last Scandinavian Ice Sheet extent and dynamics from the Middle Weichselian ice sheet advance, 50–30 ka, through the Last Glacial Maximum, 25–21 ka, and Young Baltic advances, 18–15 ka.
Jean Vérité, Édouard Ravier, Olivier Bourgeois, Stéphane Pochat, Thomas Lelandais, Régis Mourgues, Christopher D. Clark, Paul Bessin, David Peigné, and Nigel Atkinson
The Cryosphere, 15, 2889–2916, https://doi.org/10.5194/tc-15-2889-2021, https://doi.org/10.5194/tc-15-2889-2021, 2021
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Subglacial bedforms are commonly used to reconstruct past glacial dynamics and investigate processes occuring at the ice–bed interface. Using analogue modelling and geomorphological mapping, we demonstrate that ridges with undulating crests, known as subglacial ribbed bedforms, are ubiquitous features along ice stream corridors. These bedforms provide a tantalizing glimpse into (1) the former positions of ice stream margins, (2) the ice lobe dynamics and (3) the meltwater drainage efficiency.
Felix S. L. Ng
The Cryosphere, 15, 1787–1810, https://doi.org/10.5194/tc-15-1787-2021, https://doi.org/10.5194/tc-15-1787-2021, 2021
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Current theory predicts climate signals in the vein chemistry of ice cores to migrate, hampering their dating. I show that the Gibbs–Thomson effect, which has been overlooked, causes fast diffusion that prevents signals from surviving into deep ice. Hence the deep climatic peaks in Antarctic and Greenlandic ice must be due to impurities in the ice matrix (outside veins) and safe from migration. These findings reset our understanding of postdepositional changes of ice-core climate signals.
Emma L. M. Lewington, Stephen J. Livingstone, Chris D. Clark, Andrew J. Sole, and Robert D. Storrar
The Cryosphere, 14, 2949–2976, https://doi.org/10.5194/tc-14-2949-2020, https://doi.org/10.5194/tc-14-2949-2020, 2020
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We map visible traces of subglacial meltwater flow across Keewatin, Canada. Eskers are commonly observed to form within meltwater corridors up to a few kilometres wide, and we interpret different traces to have formed as part of the same integrated drainage system. In our proposed model, we suggest that eskers record the imprint of a central conduit while meltwater corridors represent the interaction with the surrounding distributed drainage system.
Adam J. Hepburn, Tom Holt, Bryn Hubbard, and Felix Ng
Geosci. Instrum. Method. Data Syst., 8, 293–313, https://doi.org/10.5194/gi-8-293-2019, https://doi.org/10.5194/gi-8-293-2019, 2019
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Currently, there exist thousands of unprocessed stereo pairs of satellite imagery which can be used to create models of the surface of Mars. This paper sets out a new open–source and free to use pipeline for creating these models. Our pipeline produces models of comparable quality to the limited number released to date but remains free to use and easily implemented by researchers, who may not necessarily have prior experience of DEM creation.
Stephen J. Livingstone, Andrew J. Sole, Robert D. Storrar, Devin Harrison, Neil Ross, and Jade Bowling
The Cryosphere, 13, 2789–2796, https://doi.org/10.5194/tc-13-2789-2019, https://doi.org/10.5194/tc-13-2789-2019, 2019
Short summary
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We report three new subglacial lakes close to the ice sheet margin of West Greenland. The lakes drained and refilled once each between 2009 and 2017, with two lakes draining in < 1 month during August 2014 and August 2015. The 2015 drainage caused a ~ 1-month down-glacier slowdown in ice flow and flooded the foreland, significantly modifying the braided river and depositing up to 8 m of sediment. These subglacial lakes offer accessible targets for future investigations and exploration.
Jeremy C. Ely, Chris D. Clark, David Small, and Richard C. A. Hindmarsh
Geosci. Model Dev., 12, 933–953, https://doi.org/10.5194/gmd-12-933-2019, https://doi.org/10.5194/gmd-12-933-2019, 2019
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During the last 2.6 million years, the Earth's climate has cycled between cold glacials and warm interglacials, causing the growth and retreat of ice sheets. These ice sheets can be independently reconstructed using numerical models or from dated evidence that they leave behind (e.g. sediments, boulders). Here, we present a tool for comparing numerical model simulations with dated ice-sheet material. We demonstrate the utility of this tool by applying it to the last British–Irish ice sheet.
Niall Gandy, Lauren J. Gregoire, Jeremy C. Ely, Christopher D. Clark, David M. Hodgson, Victoria Lee, Tom Bradwell, and Ruza F. Ivanovic
The Cryosphere, 12, 3635–3651, https://doi.org/10.5194/tc-12-3635-2018, https://doi.org/10.5194/tc-12-3635-2018, 2018
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We use the deglaciation of the last British–Irish Ice Sheet as a valuable case to examine the processes of contemporary ice sheet change, using an ice sheet model to simulate the Minch Ice Stream. We find that ice shelves were a control on retreat and that the Minch Ice Stream was vulnerable to the same marine mechanisms which threaten the future of the West Antarctic Ice Sheet. This demonstrates the importance of marine processes when projecting the future of our contemporary ice sheets.
Thomas Lelandais, Édouard Ravier, Stéphane Pochat, Olivier Bourgeois, Christopher Clark, Régis Mourgues, and Pierre Strzerzynski
The Cryosphere, 12, 2759–2772, https://doi.org/10.5194/tc-12-2759-2018, https://doi.org/10.5194/tc-12-2759-2018, 2018
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Scattered observations suggest that subglacial meltwater routes drive ice stream dynamics and ice sheet stability. We use a new experimental approach to reconcile such observations into a coherent story connecting ice stream life cycles with subglacial hydrology and bed erosion. Results demonstrate that subglacial flooding, drainage reorganization, and valley development can control an ice stream lifespan, thus opening new perspectives on subglacial processes controlling ice sheet instabilities.
Christopher N. Williams, Stephen L. Cornford, Thomas M. Jordan, Julian A. Dowdeswell, Martin J. Siegert, Christopher D. Clark, Darrel A. Swift, Andrew Sole, Ian Fenty, and Jonathan L. Bamber
The Cryosphere, 11, 363–380, https://doi.org/10.5194/tc-11-363-2017, https://doi.org/10.5194/tc-11-363-2017, 2017
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Knowledge of ice sheet bed topography and surrounding sea floor bathymetry is integral to the understanding of ice sheet processes. Existing elevation data products for Greenland underestimate fjord bathymetry due to sparse data availability. We present a new method to create physically based synthetic fjord bathymetry to fill these gaps, greatly improving on previously available datasets. This will assist in future elevation product development until further observations become available.
Stephen J. Livingstone and Chris D. Clark
Earth Surf. Dynam., 4, 567–589, https://doi.org/10.5194/esurf-4-567-2016, https://doi.org/10.5194/esurf-4-567-2016, 2016
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We mapped and analysed nearly 2000 large valleys that were formed by meltwater flowing under a former ice sheet. Our results demonstrate that valleys tend to cluster together in distinctive networks. The valleys themselves are typically < 20 km long, and 0.5–3 km wide, and their morphology is strongly influenced by local bed conditions (e.g. topography) and hydrology. We suggest valleys formed gradually, with secondary contributions from flood drainage of water stored on top of or under the ice.
A. E. Jowett, E. Hanna, F. Ng, P. Huybrechts, and I. Janssens
The Cryosphere Discuss., https://doi.org/10.5194/tcd-9-5327-2015, https://doi.org/10.5194/tcd-9-5327-2015, 2015
Revised manuscript has not been submitted
S. de la Peña, I. M. Howat, P. W. Nienow, M. R. van den Broeke, E. Mosley-Thompson, S. F. Price, D. Mair, B. Noël, and A. J. Sole
The Cryosphere, 9, 1203–1211, https://doi.org/10.5194/tc-9-1203-2015, https://doi.org/10.5194/tc-9-1203-2015, 2015
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This paper presents an assessment of changes in the near-surface structure of the accumulation zone of the Greenland Ice Sheet caused by an increase of melt at higher elevations in the last decade, especially during the unusually warm years of 2010 and 2012. The increase in melt and firn densification complicate the interpretation of changes in the ice volume, and the observed increase in firn ice content may reduce the important meltwater buffering capacity of the Greenland Ice Sheet.
C. C. Clason, D. W. F. Mair, P. W. Nienow, I. D. Bartholomew, A. Sole, S. Palmer, and W. Schwanghart
The Cryosphere, 9, 123–138, https://doi.org/10.5194/tc-9-123-2015, https://doi.org/10.5194/tc-9-123-2015, 2015
N. Chauché, A. Hubbard, J.-C. Gascard, J. E. Box, R. Bates, M. Koppes, A. Sole, P. Christoffersen, and H. Patton
The Cryosphere, 8, 1457–1468, https://doi.org/10.5194/tc-8-1457-2014, https://doi.org/10.5194/tc-8-1457-2014, 2014
H. Patton, A. Hubbard, T. Bradwell, N. F. Glasser, M. J. Hambrey, and C. D. Clark
Earth Surf. Dynam., 1, 53–65, https://doi.org/10.5194/esurf-1-53-2013, https://doi.org/10.5194/esurf-1-53-2013, 2013
S. J. Livingstone, C. D. Clark, J. Woodward, and J. Kingslake
The Cryosphere, 7, 1721–1740, https://doi.org/10.5194/tc-7-1721-2013, https://doi.org/10.5194/tc-7-1721-2013, 2013
Related subject area
Discipline: Ice sheets | Subject: Geomorphology
History and dynamics of Fennoscandian Ice Sheet retreat, contemporary ice-dammed lake evolution, and faulting in the Torneträsk area, northwestern Sweden
Dynamical response of the southwestern Laurentide Ice Sheet to rapid Bølling–Allerød warming
Ice flow dynamics of the northwestern Laurentide Ice Sheet during the last deglaciation
Effects of topographic and meteorological parameters on the surface area loss of ice aprons in the Mont Blanc massif (European Alps)
Geomorphology and shallow sub-sea-floor structures underneath the Ekström Ice Shelf, Antarctica
Formation of ribbed bedforms below shear margins and lobes of palaeo-ice streams
Ice-stream flow switching by up-ice propagation of instabilities along glacial marginal troughs
Basal control of supraglacial meltwater catchments on the Greenland Ice Sheet
How dynamic are ice-stream beds?
Subglacial drainage patterns of Devon Island, Canada: detailed comparison of rivers and subglacial meltwater channels
Karlijn Ploeg and Arjen Peter Stroeven
EGUsphere, https://doi.org/10.5194/egusphere-2024-2486, https://doi.org/10.5194/egusphere-2024-2486, 2024
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Mapping of glacial landforms using LiDAR data shows that the retreating margin of the Fennoscandian Ice Sheet dammed a series of lakes in the Torneträsk Basin during deglaciation. These lakes were more extensive than previously thought and produced outburst floods. We show that sections of the Pärvie Fault, the longest glacially-activated fault of Sweden, ruptured at different times, both underneath and in front of the ice sheet, and during the existence of ice-dammed lake Torneträsk.
Sophie L. Norris, Martin Margold, David J. A. Evans, Nigel Atkinson, and Duane G. Froese
The Cryosphere, 18, 1533–1559, https://doi.org/10.5194/tc-18-1533-2024, https://doi.org/10.5194/tc-18-1533-2024, 2024
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Associated with climate change between the Last Glacial Maximum and the current interglacial period, we reconstruct the behaviour of the southwestern Laurentide Ice Sheet, which covered the Canadian Prairies, using detailed landform mapping. Our reconstruction depicts three shifts in the ice sheet’s dynamics. We suggest these changes resulted from ice sheet thinning triggered by abrupt climatic change. However, we show that regional lithology and topography also play an important role.
Benjamin J. Stoker, Helen E. Dulfer, Chris R. Stokes, Victoria H. Brown, Christopher D. Clark, Colm Ó Cofaigh, David J. A. Evans, Duane Froese, Sophie L. Norris, and Martin Margold
EGUsphere, https://doi.org/10.5194/egusphere-2024-137, https://doi.org/10.5194/egusphere-2024-137, 2024
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The retreat of the northwestern Laurentide Ice Sheet allows us to investigate how the ice drainage network evolves over millennial timescales and understand the influence of climate forcing, glacial lakes, and the underlying geology on the rate of deglaciation. We reconstruct the changes in ice flow at 500-year intervals and identify rapid reorganisations of the drainage network, including variations in ice streaming that we link to climatically-driven changes in the ice sheet surface slope.
Suvrat Kaushik, Ludovic Ravanel, Florence Magnin, Yajing Yan, Emmanuel Trouve, and Diego Cusicanqui
The Cryosphere, 16, 4251–4271, https://doi.org/10.5194/tc-16-4251-2022, https://doi.org/10.5194/tc-16-4251-2022, 2022
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Climate change impacts all parts of the cryosphere but most importantly the smaller ice bodies like ice aprons (IAs). This study is the first attempt on a regional scale to assess the impacts of the changing climate on these small but very important ice bodies. Our study shows that IAs have consistently lost mass over the past decades. The effects of climate variables, particularly temperature and precipitation and topographic factors, were analysed on the loss of IA area.
Astrid Oetting, Emma C. Smith, Jan Erik Arndt, Boris Dorschel, Reinhard Drews, Todd A. Ehlers, Christoph Gaedicke, Coen Hofstede, Johann P. Klages, Gerhard Kuhn, Astrid Lambrecht, Andreas Läufer, Christoph Mayer, Ralf Tiedemann, Frank Wilhelms, and Olaf Eisen
The Cryosphere, 16, 2051–2066, https://doi.org/10.5194/tc-16-2051-2022, https://doi.org/10.5194/tc-16-2051-2022, 2022
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This study combines a variety of geophysical measurements in front of and beneath the Ekström Ice Shelf in order to identify and interpret geomorphological evidences of past ice sheet flow, extent and retreat.
The maximal extent of grounded ice in this region was 11 km away from the continental shelf break.
The thickness of palaeo-ice on the calving front around the LGM was estimated to be at least 305 to 320 m.
We provide essential boundary conditions for palaeo-ice-sheet models.
Jean Vérité, Édouard Ravier, Olivier Bourgeois, Stéphane Pochat, Thomas Lelandais, Régis Mourgues, Christopher D. Clark, Paul Bessin, David Peigné, and Nigel Atkinson
The Cryosphere, 15, 2889–2916, https://doi.org/10.5194/tc-15-2889-2021, https://doi.org/10.5194/tc-15-2889-2021, 2021
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Subglacial bedforms are commonly used to reconstruct past glacial dynamics and investigate processes occuring at the ice–bed interface. Using analogue modelling and geomorphological mapping, we demonstrate that ridges with undulating crests, known as subglacial ribbed bedforms, are ubiquitous features along ice stream corridors. These bedforms provide a tantalizing glimpse into (1) the former positions of ice stream margins, (2) the ice lobe dynamics and (3) the meltwater drainage efficiency.
Etienne Brouard and Patrick Lajeunesse
The Cryosphere, 13, 981–996, https://doi.org/10.5194/tc-13-981-2019, https://doi.org/10.5194/tc-13-981-2019, 2019
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Modifications in ice-stream networks have major impacts on ice sheet mass balance and global sea level. However, the mechanisms controlling ice-stream switching remain poorly understood. We report a flow switch in an ice-stream system that occurred on the Baffin Island shelf through the erosion of a marginal trough. Up-ice propagation of ice streams through marginal troughs can lead to the piracy of neighboring ice catchments, which induces an adjacent ice-stream switch and shutdown.
Josh Crozier, Leif Karlstrom, and Kang Yang
The Cryosphere, 12, 3383–3407, https://doi.org/10.5194/tc-12-3383-2018, https://doi.org/10.5194/tc-12-3383-2018, 2018
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Understanding ice sheet surface meltwater routing is important for modeling and predicting ice sheet evolution. We determined that bed topography underlying the Greenland Ice Sheet is the primary influence on 1–10 km scale ice surface topography, and on drainage-basin-scale surface meltwater routing. We provide a simple means of predicting the response of surface meltwater routing to changing ice flow conditions and explore the implications of this for subglacial hydrology.
Damon Davies, Robert G. Bingham, Edward C. King, Andrew M. Smith, Alex M. Brisbourne, Matteo Spagnolo, Alastair G. C. Graham, Anna E. Hogg, and David G. Vaughan
The Cryosphere, 12, 1615–1628, https://doi.org/10.5194/tc-12-1615-2018, https://doi.org/10.5194/tc-12-1615-2018, 2018
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This paper investigates the dynamics of ice stream beds using repeat geophysical surveys of the bed of Pine Island Glacier, West Antarctica; 60 km of the bed was surveyed, comprising the most extensive repeat ground-based geophysical surveys of an Antarctic ice stream; 90 % of the surveyed bed shows no significant change despite the glacier increasing in speed by up to 40 % over the last decade. This result suggests that ice stream beds are potentially more stable than previously suggested.
Anna Grau Galofre, A. Mark Jellinek, Gordon R. Osinski, Michael Zanetti, and Antero Kukko
The Cryosphere, 12, 1461–1478, https://doi.org/10.5194/tc-12-1461-2018, https://doi.org/10.5194/tc-12-1461-2018, 2018
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Water accumulated at the base of ice sheets is the main driver of glacier acceleration and loss of ice mass in Arctic regions. Previously glaciated landscapes sculpted by this water carry information about how ice sheets collapse and ultimately disappear. The search for these landscapes took us to the high Arctic, to explore channels that formed under kilometers of ice during the last ice age. In this work we describe how subglacial channels look and how they helped to drain an ice sheet.
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Short summary
We map series of aligned mounds (esker beads) across central Nunavut, Canada. Mounds are interpreted to have formed roughly annually as sediment carried by subglacial rivers is deposited at the ice margin. Chains of mounds are formed as the ice retreats. This high-resolution (annual) record allows us to constrain the pace of ice retreat, sediment fluxes, and the style of drainage through time. In particular, we suggest that eskers in general record a composite signature of ice-marginal drainage.
We map series of aligned mounds (esker beads) across central Nunavut, Canada. Mounds are...