Articles | Volume 17, issue 4
https://doi.org/10.5194/tc-17-1787-2023
© Author(s) 2023. 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-17-1787-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| Highlight paper
| 
28 Apr 2023
Research article | Highlight paper |
| 28 Apr 2023
| 28 Apr 2023
Reversible ice sheet thinning in the Amundsen Sea Embayment during the Late Holocene
Greg Balco
CORRESPONDING AUTHOR
Berkeley Geochronology Center, Berkeley, CA, USA
Nathan Brown
Earth and Environmental Sciences, University of Texas Arlington, Arlington, TX, USA
Keir Nichols
Earth Science and Engineering, Imperial College London, London, UK
Ryan A. Venturelli
Geology and Geological Engineering, Colorado School of Mines, Golden, CO, USA
Jonathan Adams
Earth Science and Engineering, Imperial College London, London, UK
British Antarctic Survey, Cambridge, UK
Scott Braddock
School of Earth and Climate Sciences, University of Maine, Orono, ME, USA
Seth Campbell
School of Earth and Climate Sciences, University of Maine, Orono, ME, USA
Brent Goehring
Earth and Environmental Sciences, Tulane University, New Orleans, LA, USA
Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, USA
Joanne S. Johnson
British Antarctic Survey, Cambridge, UK
Dylan H. Rood
Earth Science and Engineering, Imperial College London, London, UK
Klaus Wilcken
Australian National Science and Technology Organisation (ANSTO), Lucas Heights, NSW, Australia
Brenda Hall
School of Earth and Climate Sciences, University of Maine, Orono, ME, USA
John Woodward
Geography and Environmental Sciences, Northumbria University, Newcastle-upon-Tyne, UK
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Cosmogenic nuclide exposure dating is an exceptional tool for reconstructing glacier histories, but reconstructions based on common target nuclides (e.g., 10Be) can be costly and time-consuming to generate. Here, we present a cost-effective proof-of-concept 21Ne exposure age chronology from Lassen Volcanic National Park, CA, USA, that broadly agrees with nearby 10Be chronologies but at lower precision.
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Determining where and when the Antarctic ice sheet was smaller than present requires recovery and exposure dating of subglacial bedrock. Here we use ice sheet model outputs and field data (geological and glaciological observations, bedrock samples and ground-penetrating radar from subglacial ridges) to assess the suitability for drilling of sites in the Hudson Mountains, West Antarctica. We find that no sites are perfect, but two are feasible, with the most suitable being Winkie Nunatak.
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Cosmogenic nuclides like 10Be are rare isotopes created in rocks exposed at the Earth’s surface and can be used to understand glacier histories and landscape evolution. 10Be is usually measured in the mineral quartz. Here, we show that 10Be can be reliably measured in the mineral pyroxene. We use the measurements to determine exposure ages and understand landscape processes in rocks from Antarctica that do not have quartz, expanding the use of this method to new rock types.
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Geologic dating methods generally do not directly measure ages. Instead, interpreting a geochemical measurement as an age requires a middle layer of calculations and supporting data, and the fact that this layer continually improves is an obstacle to synoptic analysis of geochronological data. This paper describes a prototype data management and analysis system that addresses this obstacle by making the middle-layer calculations transparent and dynamic to the user.
Michal Ben-Israel, Ari Matmon, Alan J. Hidy, Yoav Avni, and Greg Balco
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Early-to-mid Miocene erosion rates were inferred using cosmogenic 21Ne measured in chert pebbles transported by the Miocene Hazeva River (~ 18 Ma). Miocene erosion rates are faster compared to Quaternary rates in the region. Faster Miocene erosion rates could be due to a response to topographic changes brought on by tectonic uplift, wetter climate in the region during the Miocene, or a combination of both.
Keir A. Nichols, Brent M. Goehring, Greg Balco, Joanne S. Johnson, Andrew S. Hein, and Claire Todd
The Cryosphere, 13, 2935–2951, https://doi.org/10.5194/tc-13-2935-2019, https://doi.org/10.5194/tc-13-2935-2019, 2019
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We studied the history of ice masses at three locations in the Weddell Sea Embayment, Antarctica. We measured rare isotopes in material sourced from mountains overlooking the Slessor Glacier, Foundation Ice Stream, and smaller glaciers on the Lassiter Coast. We show that ice masses were between 385 and 800 m thicker during the last glacial cycle than they are at present. The ice masses were both hundreds of metres thicker and remained thicker closer to the present than was previously thought.
Greg Balco, Kimberly Blisniuk, and Alan Hidy
Geochronology, 1, 1–16, https://doi.org/10.5194/gchron-1-1-2019, https://doi.org/10.5194/gchron-1-1-2019, 2019
Short summary
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This article applies a new geochemical dating method to determine the age of sedimentary deposits useful in reconstructing slip rates on a major fault system.
Jonathan R. Adams, Dylan H. Rood, Klaus Wilcken, Stephen J. Roberts, and Joanne S. Johnson
Geochronology Discuss., https://doi.org/10.5194/gchron-2024-34, https://doi.org/10.5194/gchron-2024-34, 2024
Preprint under review for GChron
Short summary
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Ice sheet mass loss is adding to sea-level rise, and is expected to increase, but by how much and how fast remains uncertain. Isotopes produced in rock at the Earth’s surface provide records of past ice sheet thinning which help predict future change but are more effective if they are precise enough to determine past changes to the nearest thousand years. The precision of carbon-14, an isotope which is guaranteed to record past change since the last ice age, can be improved.
Joseph P. Tulenko, Greg Balco, Michael A. Clynne, and L. J. Patrick Muffler
Geochronology, 6, 639–652, https://doi.org/10.5194/gchron-6-639-2024, https://doi.org/10.5194/gchron-6-639-2024, 2024
Short summary
Short summary
Cosmogenic nuclide exposure dating is an exceptional tool for reconstructing glacier histories, but reconstructions based on common target nuclides (e.g., 10Be) can be costly and time-consuming to generate. Here, we present a cost-effective proof-of-concept 21Ne exposure age chronology from Lassen Volcanic National Park, CA, USA, that broadly agrees with nearby 10Be chronologies but at lower precision.
Greg Balco, Andrew J. Conant, Dallas D. Reilly, Dallin Barton, Chelsea D. Willett, and Brett H. Isselhardt
Geochronology, 6, 571–584, https://doi.org/10.5194/gchron-6-571-2024, https://doi.org/10.5194/gchron-6-571-2024, 2024
Short summary
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This paper describes how krypton isotopes produced by nuclear fission can be used to determine the age of microscopic particles of used nuclear fuel. This is potentially useful for international safeguard applications aimed at tracking and identifying nuclear materials, as well as geoscience applications involving dating post-1950s sediments or understanding environmental transport of nuclear materials.
Nicolas Bakken-French, Stephen J. Boyer, B. Clay Southworth, Megan Thayne, Dylan H. Rood, and Anders E. Carlson
The Cryosphere, 18, 4517–4530, https://doi.org/10.5194/tc-18-4517-2024, https://doi.org/10.5194/tc-18-4517-2024, 2024
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Repeat photography, field mapping, and remote sensing find that glaciers on Mt. Hood, Oregon, have lost about 25 % of their area in the first 2 decades of the 21st century and 17 % of their area in the last 7–8 years. The 21st century recession rate is more than 3 times faster than the 20th century average and 1.9 times faster than the fastest period of retreat within the 20th century. This unprecedented retreat corresponds to regional summer warming of 1.7–1.8°C relative to the early 1900s.
Allie Balter-Kennedy, Joerg M. Schaefer, Greg Balco, Meredith A. Kelly, Michael R. Kaplan, Roseanne Schwartz, Bryan Oakley, Nicolás E. Young, Jean Hanley, and Arianna M. Varuolo-Clarke
Clim. Past, 20, 2167–2190, https://doi.org/10.5194/cp-20-2167-2024, https://doi.org/10.5194/cp-20-2167-2024, 2024
Short summary
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We date sedimentary deposits showing that the southeastern Laurentide Ice Sheet was at or near its southernmost extent from ~ 26 000 to 21 000 years ago, when sea levels were at their lowest, with climate records indicating glacial conditions. Slow deglaciation began ~ 22 000 years ago, shown by a rise in modeled local summer temperatures, but significant deglaciation in the region did not begin until ~ 18 000 years ago, when atmospheric CO2 began to rise, marking the end of the last ice age.
Marie Bergelin, Greg Balco, Lee B. Corbett, and Paul R. Bierman
Geochronology, 6, 491–502, https://doi.org/10.5194/gchron-6-491-2024, https://doi.org/10.5194/gchron-6-491-2024, 2024
Short summary
Short summary
Cosmogenic nuclides, such as 10Be, are rare isotopes produced in rocks when exposed at Earth's surface and are valuable for understanding surface processes and landscape evolution. However, 10Be is usually measured in quartz minerals. Here we present advances in efficiently extracting and measuring 10Be in the pyroxene mineral. These measurements expand the use of 10Be as a dating tool for new rock types and provide opportunities to understand landscape processes in areas that lack quartz.
Joanne S. Johnson, John Woodward, Ian Nesbitt, Kate Winter, Seth Campbell, Keir A. Nichols, Ryan A. Venturelli, Scott Braddock, Brent M. Goehring, Brenda Hall, Dylan H. Rood, and Greg Balco
EGUsphere, https://doi.org/10.5194/egusphere-2024-1452, https://doi.org/10.5194/egusphere-2024-1452, 2024
Short summary
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Determining where and when the Antarctic ice sheet was smaller than present requires recovery and exposure dating of subglacial bedrock. Here we use ice sheet model outputs and field data (geological and glaciological observations, bedrock samples and ground-penetrating radar from subglacial ridges) to assess the suitability for drilling of sites in the Hudson Mountains, West Antarctica. We find that no sites are perfect, but two are feasible, with the most suitable being Winkie Nunatak.
Gordon Bromley, Greg Balco, Margaret Jackson, Allie Balter-Kennedy, and Holly Thomas
Clim. Past Discuss., https://doi.org/10.5194/cp-2024-21, https://doi.org/10.5194/cp-2024-21, 2024
Revised manuscript accepted for CP
Short summary
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We constructed a geologic record of East Antarctic Ice Sheet thickness from deposits at Otway Massif to assess directly how Earth’s largest ice sheet responds to warmer-than-present climate. Our record confirms the long-term dominance of a cold polar climate but lacks a clear ice sheet response to the Mid Pliocene Warm Period, a common analogue for the future. Instead, an absence of moraines from the Late Miocene-Early Pliocene suggests the ice sheet was less extensive than present at that time.
Greg Balco, Alan J. Hidy, William T. Struble, and Joshua J. Roering
Geochronology, 6, 71–76, https://doi.org/10.5194/gchron-6-71-2024, https://doi.org/10.5194/gchron-6-71-2024, 2024
Short summary
Short summary
We describe a new method of reconstructing the long-term, pre-observational frequency and/or intensity of wildfires in forested landscapes using trace concentrations of the noble gases helium and neon that are formed in soil mineral grains by cosmic-ray bombardment of the Earth's surface.
Jacob T. H. Anderson, Toshiyuki Fujioka, David Fink, Alan J. Hidy, Gary S. Wilson, Klaus Wilcken, Andrey Abramov, and Nikita Demidov
The Cryosphere, 17, 4917–4936, https://doi.org/10.5194/tc-17-4917-2023, https://doi.org/10.5194/tc-17-4917-2023, 2023
Short summary
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Antarctic permafrost processes are not widely studied or understood in the McMurdo Dry Valleys. Our data show that near-surface permafrost sediments were deposited ~180 000 years ago in Pearse Valley, while in lower Wright Valley sediments are either vertically mixed after deposition or were deposited < 25 000 years ago. Our data also record Taylor Glacier retreat from Pearse Valley ~65 000–74 000 years ago and support antiphase dynamics between alpine glaciers and sea ice in the Ross Sea.
Ling Fang, Theo M. Jenk, Dominic Winski, Karl Kreutz, Hanna L. Brooks, Emma Erwin, Erich Osterberg, Seth Campbell, Cameron Wake, and Margit Schwikowski
The Cryosphere, 17, 4007–4020, https://doi.org/10.5194/tc-17-4007-2023, https://doi.org/10.5194/tc-17-4007-2023, 2023
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Understanding the behavior of ocean–atmosphere teleconnections in the North Pacific during warm intervals can aid in predicting future warming scenarios. However, majority ice core records from Alaska–Yukon region only provide data for the last few centuries. This study introduces a continuous chronology for Denali ice core from Begguya, Alaska, using multiple dating methods. The early-Holocene-origin Denali ice core will facilitate future investigations of hydroclimate in the North Pacific.
Benoit S. Lecavalier, Lev Tarasov, Greg Balco, Perry Spector, Claus-Dieter Hillenbrand, Christo Buizert, Catherine Ritz, Marion Leduc-Leballeur, Robert Mulvaney, Pippa L. Whitehouse, Michael J. Bentley, and Jonathan Bamber
Earth Syst. Sci. Data, 15, 3573–3596, https://doi.org/10.5194/essd-15-3573-2023, https://doi.org/10.5194/essd-15-3573-2023, 2023
Short summary
Short summary
The Antarctic Ice Sheet Evolution constraint database version 2 (AntICE2) consists of a large variety of observations that constrain the evolution of the Antarctic Ice Sheet over the last glacial cycle. This includes observations of past ice sheet extent, past ice thickness, past relative sea level, borehole temperature profiles, and present-day bedrock displacement rates. The database is intended to improve our understanding of past Antarctic changes and for ice sheet model calibrations.
Allie Balter-Kennedy, Joerg M. Schaefer, Roseanne Schwartz, Jennifer L. Lamp, Laura Penrose, Jennifer Middleton, Jean Hanley, Bouchaïb Tibari, Pierre-Henri Blard, Gisela Winckler, Alan J. Hidy, and Greg Balco
Geochronology, 5, 301–321, https://doi.org/10.5194/gchron-5-301-2023, https://doi.org/10.5194/gchron-5-301-2023, 2023
Short summary
Short summary
Cosmogenic nuclides like 10Be are rare isotopes created in rocks exposed at the Earth’s surface and can be used to understand glacier histories and landscape evolution. 10Be is usually measured in the mineral quartz. Here, we show that 10Be can be reliably measured in the mineral pyroxene. We use the measurements to determine exposure ages and understand landscape processes in rocks from Antarctica that do not have quartz, expanding the use of this method to new rock types.
Jennifer R. Shadrick, Dylan H. Rood, Martin D. Hurst, Matthew D. Piggott, Klaus M. Wilcken, and Alexander J. Seal
Earth Surf. Dynam., 11, 429–450, https://doi.org/10.5194/esurf-11-429-2023, https://doi.org/10.5194/esurf-11-429-2023, 2023
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This study uses a coastal evolution model to interpret cosmogenic beryllium-10 concentrations and topographic data and, in turn, quantify long-term cliff retreat rates for four chalk sites on the south coast of England. By using a process-based model, clear distinctions between intertidal weathering rates have been recognised between chalk and sandstone rock coast sites, advocating the use of process-based models to interpret the long-term behaviour of rock coasts.
Anna Ruth W. Halberstadt, Greg Balco, Hannah Buchband, and Perry Spector
The Cryosphere, 17, 1623–1643, https://doi.org/10.5194/tc-17-1623-2023, https://doi.org/10.5194/tc-17-1623-2023, 2023
Short summary
Short summary
This paper explores the use of multimillion-year exposure ages from Antarctic bedrock outcrops to benchmark ice sheet model predictions and thereby infer ice sheet sensitivity to warm climates. We describe a new approach for model–data comparison, highlight an example where observational data are used to distinguish end-member models, and provide guidance for targeted sampling around Antarctica that can improve understanding of ice sheet response to climate warming in the past and future.
Jonathan R. Adams, Joanne S. Johnson, Stephen J. Roberts, Philippa J. Mason, Keir A. Nichols, Ryan A. Venturelli, Klaus Wilcken, Greg Balco, Brent Goehring, Brenda Hall, John Woodward, and Dylan H. Rood
The Cryosphere, 16, 4887–4905, https://doi.org/10.5194/tc-16-4887-2022, https://doi.org/10.5194/tc-16-4887-2022, 2022
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Glaciers in West Antarctica are experiencing significant ice loss. Geological data provide historical context for ongoing ice loss in West Antarctica, including constraints on likely future ice sheet behaviour in response to climatic warming. We present evidence from rare isotopes measured in rocks collected from an outcrop next to Pope Glacier. These data suggest that Pope Glacier thinned faster and sooner after the last ice age than previously thought.
Natacha Gribenski, Marissa M. Tremblay, Pierre G. Valla, Greg Balco, Benny Guralnik, and David L. Shuster
Geochronology, 4, 641–663, https://doi.org/10.5194/gchron-4-641-2022, https://doi.org/10.5194/gchron-4-641-2022, 2022
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We apply quartz 3He paleothermometry along two deglaciation profiles in the European Alps to reconstruct temperature evolution since the Last Glacial Maximum. We observe a 3He thermal signal clearly colder than today in all bedrock surface samples exposed prior the Holocene. Current uncertainties in 3He diffusion kinetics do not permit distinguishing if this signal results from Late Pleistocene ambient temperature changes or from recent ground temperature variation due to permafrost degradation.
Ingalise Kindstedt, Kristin M. Schild, Dominic Winski, Karl Kreutz, Luke Copland, Seth Campbell, and Erin McConnell
The Cryosphere, 16, 3051–3070, https://doi.org/10.5194/tc-16-3051-2022, https://doi.org/10.5194/tc-16-3051-2022, 2022
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We show that neither the large spatial footprint of the MODIS sensor nor poorly constrained snow emissivity values explain the observed cold offset in MODIS land surface temperatures (LSTs) in the St. Elias. Instead, the offset is most prominent under conditions associated with near-surface temperature inversions. This work represents an advance in the application of MODIS LSTs to glaciated alpine regions, where we often depend solely on remote sensing products for temperature information.
Marie Bergelin, Jaakko Putkonen, Greg Balco, Daniel Morgan, Lee B. Corbett, and Paul R. Bierman
The Cryosphere, 16, 2793–2817, https://doi.org/10.5194/tc-16-2793-2022, https://doi.org/10.5194/tc-16-2793-2022, 2022
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Glacier ice contains information on past climate and can help us understand how the world changes through time. We have found and sampled a buried ice mass in Antarctica that is much older than most ice on Earth and difficult to date. Therefore, we developed a new dating application which showed the ice to be 3 million years old. Our new dating solution will potentially help to date other ancient ice masses since such old glacial ice could yield data on past environmental conditions on Earth.
Mae Kate Campbell, Paul R. Bierman, Amanda H. Schmidt, Rita Sibello Hernández, Alejandro García-Moya, Lee B. Corbett, Alan J. Hidy, Héctor Cartas Águila, Aniel Guillén Arruebarrena, Greg Balco, David Dethier, and Marc Caffee
Geochronology, 4, 435–453, https://doi.org/10.5194/gchron-4-435-2022, https://doi.org/10.5194/gchron-4-435-2022, 2022
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We used cosmogenic radionuclides in detrital river sediment to measure erosion rates of watersheds in central Cuba; erosion rates are lower than rock dissolution rates in lowland watersheds. Data from two different cosmogenic nuclides suggest that some basins may have a mixed layer deeper than is typically modeled and could have experienced significant burial after or during exposure. We conclude that significant mass loss may occur at depth through chemical weathering processes.
Klaus M. Wilcken, Alexandru T. Codilean, Réka-H. Fülöp, Steven Kotevski, Anna H. Rood, Dylan H. Rood, Alexander J. Seal, and Krista Simon
Geochronology, 4, 339–352, https://doi.org/10.5194/gchron-4-339-2022, https://doi.org/10.5194/gchron-4-339-2022, 2022
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Cosmogenic nuclides are now widely applied in the Earth sciences; however, more recent applications often push the analytical limits of the technique. Our study presents a comprehensive method for analysis of cosmogenic 10Be and 26Al samples down to isotope concentrations of a few thousand atoms per gram of sample, which opens the door to new and more varied applications of cosmogenic nuclide analysis.
Brent M. Goehring, Brian Menounos, Gerald Osborn, Adam Hawkins, and Brent Ward
Geochronology, 4, 311–322, https://doi.org/10.5194/gchron-4-311-2022, https://doi.org/10.5194/gchron-4-311-2022, 2022
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We explored surface exposure dating with two nuclides to date two sets of moraines from the Yukon Territory and explain the reasoning for the observed ages. Results suggest multiple processes, including preservation of nuclides from a prior exposure period, and later erosion of the moraines is required to explain the data. Our results only allow for the older moraines to date to Marine Isotope Stage 3 or 4 and the younger moraines to date to the very earliest Holocene.
Joanne S. Johnson, Ryan A. Venturelli, Greg Balco, Claire S. Allen, Scott Braddock, Seth Campbell, Brent M. Goehring, Brenda L. Hall, Peter D. Neff, Keir A. Nichols, Dylan H. Rood, Elizabeth R. Thomas, and John Woodward
The Cryosphere, 16, 1543–1562, https://doi.org/10.5194/tc-16-1543-2022, https://doi.org/10.5194/tc-16-1543-2022, 2022
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Recent studies have suggested that some portions of the Antarctic Ice Sheet were less extensive than present in the last few thousand years. We discuss how past ice loss and regrowth during this time would leave its mark on geological and glaciological records and suggest ways in which future studies could detect such changes. Determining timing of ice loss and gain around Antarctica and conditions under which they occurred is critical for preparing for future climate-warming-induced changes.
Jamey Stutz, Andrew Mackintosh, Kevin Norton, Ross Whitmore, Carlo Baroni, Stewart S. R. Jamieson, Richard S. Jones, Greg Balco, Maria Cristina Salvatore, Stefano Casale, Jae Il Lee, Yeong Bae Seong, Robert McKay, Lauren J. Vargo, Daniel Lowry, Perry Spector, Marcus Christl, Susan Ivy Ochs, Luigia Di Nicola, Maria Iarossi, Finlay Stuart, and Tom Woodruff
The Cryosphere, 15, 5447–5471, https://doi.org/10.5194/tc-15-5447-2021, https://doi.org/10.5194/tc-15-5447-2021, 2021
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Understanding the long-term behaviour of ice sheets is essential to projecting future changes due to climate change. In this study, we use rocks deposited along the margin of the David Glacier, one of the largest glacier systems in the world, to reveal a rapid thinning event initiated over 7000 years ago and endured for ~ 2000 years. Using physical models, we show that subglacial topography and ocean heat are important drivers for change along this sector of the Antarctic Ice Sheet.
Jennifer R. Shadrick, Martin D. Hurst, Matthew D. Piggott, Bethany G. Hebditch, Alexander J. Seal, Klaus M. Wilcken, and Dylan H. Rood
Earth Surf. Dynam., 9, 1505–1529, https://doi.org/10.5194/esurf-9-1505-2021, https://doi.org/10.5194/esurf-9-1505-2021, 2021
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Here we use topographic and 10Be concentration data to optimise a coastal evolution model. Cliff retreat rates are calculated for two UK sites for the past 8000 years and, for the first time, highlight a strong link between the rate of sea level rise and long-term cliff retreat rates. This method enables us to study past cliff response to sea level rise and so to greatly improve forecasts of future responses to accelerations in sea level rise that will result from climate change.
Trevor R. Hillebrand, John O. Stone, Michelle Koutnik, Courtney King, Howard Conway, Brenda Hall, Keir Nichols, Brent Goehring, and Mette K. Gillespie
The Cryosphere, 15, 3329–3354, https://doi.org/10.5194/tc-15-3329-2021, https://doi.org/10.5194/tc-15-3329-2021, 2021
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We present chronologies from Darwin and Hatherton glaciers to better constrain ice sheet retreat during the last deglaciation in the Ross Sector of Antarctica. We use a glacier flowband model and an ensemble of 3D ice sheet model simulations to show that (i) the whole glacier system likely thinned steadily from about 9–3 ka, and (ii) the grounding line likely reached the Darwin–Hatherton Glacier System at about 3 ka, which is ≥3.8 kyr later than was suggested by previous reconstructions.
Greg Balco, Benjamin D. DeJong, John C. Ridge, Paul R. Bierman, and Dylan H. Rood
Geochronology, 3, 1–33, https://doi.org/10.5194/gchron-3-1-2021, https://doi.org/10.5194/gchron-3-1-2021, 2021
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The North American Varve Chronology (NAVC) is a sequence of 5659 annual sedimentary layers that were deposited in proglacial lakes adjacent to the retreating Laurentide Ice Sheet ca. 12 500–18 200 years ago. We attempt to synchronize this record with Greenland ice core and other climate records that cover the same time period by detecting variations in global fallout of atmospherically produced beryllium-10 in NAVC sediments.
Kate Winter, Emily A. Hill, G. Hilmar Gudmundsson, and John Woodward
Earth Syst. Sci. Data, 12, 3453–3467, https://doi.org/10.5194/essd-12-3453-2020, https://doi.org/10.5194/essd-12-3453-2020, 2020
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Satellite measurements of the English Coast in the Antarctic Peninsula reveal that glaciers are thinning and losing mass, but ice thickness data are required to assess these changes, in terms of ice flux and sea level contribution. Our ice-penetrating radar measurements reveal that low-elevation subglacial channels control fast-flowing ice streams, which release over 39 Gt of ice per year to floating ice shelves. This topography could make ice flows susceptible to future instability.
Allie Balter-Kennedy, Gordon Bromley, Greg Balco, Holly Thomas, and Margaret S. Jackson
The Cryosphere, 14, 2647–2672, https://doi.org/10.5194/tc-14-2647-2020, https://doi.org/10.5194/tc-14-2647-2020, 2020
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We describe new geologic evidence from Antarctica that demonstrates changes in East Antarctic Ice Sheet (EAIS) extent over the past ~ 15 million years. Our data show that the EAIS was a persistent feature in the Transantarctic Mountains for much of that time, including some (but not all) times when global temperature may have been warmer than today. Overall, our results comprise a long-term record of EAIS change and may provide useful constraints for ice sheet models and sea-level estimates.
Greg Balco
Geochronology, 2, 169–175, https://doi.org/10.5194/gchron-2-169-2020, https://doi.org/10.5194/gchron-2-169-2020, 2020
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Geologic dating methods generally do not directly measure ages. Instead, interpreting a geochemical measurement as an age requires a middle layer of calculations and supporting data, and the fact that this layer continually improves is an obstacle to synoptic analysis of geochronological data. This paper describes a prototype data management and analysis system that addresses this obstacle by making the middle-layer calculations transparent and dynamic to the user.
Michal Ben-Israel, Ari Matmon, Alan J. Hidy, Yoav Avni, and Greg Balco
Earth Surf. Dynam., 8, 289–301, https://doi.org/10.5194/esurf-8-289-2020, https://doi.org/10.5194/esurf-8-289-2020, 2020
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Early-to-mid Miocene erosion rates were inferred using cosmogenic 21Ne measured in chert pebbles transported by the Miocene Hazeva River (~ 18 Ma). Miocene erosion rates are faster compared to Quaternary rates in the region. Faster Miocene erosion rates could be due to a response to topographic changes brought on by tectonic uplift, wetter climate in the region during the Miocene, or a combination of both.
Perry Spector, John Stone, and Brent Goehring
The Cryosphere, 13, 3061–3075, https://doi.org/10.5194/tc-13-3061-2019, https://doi.org/10.5194/tc-13-3061-2019, 2019
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We describe constraints on the thickness of the interior of the West Antarctic Ice Sheet (WAIS) through the last deglaciation. Our data imply that the ice-sheet divide between the Ross and Weddell sea sectors of the WAIS was thicker than present for a period less than ~ 8 kyr within the past ~ 15 kyr. These results are consistent with the hypothesis that the divide initially thickened due to the deglacial rise in snowfall and subsequently thinned in response to retreat of the ice-sheet margin.
Keir A. Nichols, Brent M. Goehring, Greg Balco, Joanne S. Johnson, Andrew S. Hein, and Claire Todd
The Cryosphere, 13, 2935–2951, https://doi.org/10.5194/tc-13-2935-2019, https://doi.org/10.5194/tc-13-2935-2019, 2019
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We studied the history of ice masses at three locations in the Weddell Sea Embayment, Antarctica. We measured rare isotopes in material sourced from mountains overlooking the Slessor Glacier, Foundation Ice Stream, and smaller glaciers on the Lassiter Coast. We show that ice masses were between 385 and 800 m thicker during the last glacial cycle than they are at present. The ice masses were both hundreds of metres thicker and remained thicker closer to the present than was previously thought.
Keir A. Nichols and Brent M. Goehring
Geochronology, 1, 43–52, https://doi.org/10.5194/gchron-1-43-2019, https://doi.org/10.5194/gchron-1-43-2019, 2019
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We describe observations of anomalously high measurements of C-14 made from geologic material. We undertake a systematic investigation to identify the source of contamination, which we hypothesise is sourced from a commonly used method that is used prior to sample analysis. We find that the method does introduce modern carbon to samples and elevates C-14 measurements. We describe a standard procedure that effectively removes contamination from the aforementioned method.
Greg Balco, Kimberly Blisniuk, and Alan Hidy
Geochronology, 1, 1–16, https://doi.org/10.5194/gchron-1-1-2019, https://doi.org/10.5194/gchron-1-1-2019, 2019
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This article applies a new geochemical dating method to determine the age of sedimentary deposits useful in reconstructing slip rates on a major fault system.
Charlotte P. Iverach, Dioni I. Cendón, Karina T. Meredith, Klaus M. Wilcken, Stuart I. Hankin, Martin S. Andersen, and Bryce F. J. Kelly
Hydrol. Earth Syst. Sci., 21, 5953–5969, https://doi.org/10.5194/hess-21-5953-2017, https://doi.org/10.5194/hess-21-5953-2017, 2017
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This study uses a multi-tracer geochemical approach to determine the extent of artesian groundwater discharge into an economically important alluvial aquifer. We compare estimates for artesian discharge into the alluvial aquifer derived from water balance modelling and geochemical data to show that there is considerable divergence in the results. The implications of this work involve highlighting that geochemical data should be used as a critical component of water budget assessments.
Stephanie L. Strother, Ulrich Salzmann, Francesca Sangiorgi, Peter K. Bijl, Jörg Pross, Carlota Escutia, Ariadna Salabarnada, Matthew J. Pound, Jochen Voss, and John Woodward
Biogeosciences, 14, 2089–2100, https://doi.org/10.5194/bg-14-2089-2017, https://doi.org/10.5194/bg-14-2089-2017, 2017
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One of the main challenges in Antarctic vegetation reconstructions is the uncertainty in unambiguously identifying reworked pollen and spore assemblages in marine sedimentary records influenced by waxing and waning ice sheets. This study uses red fluorescence and digital imaging as a new tool to identify reworking in a marine sediment core from circum-Antarctic waters to reconstruct Cenozoic climate change and vegetation with high confidence.
Martin D. Hurst, Dylan H. Rood, and Michael A. Ellis
Earth Surf. Dynam., 5, 67–84, https://doi.org/10.5194/esurf-5-67-2017, https://doi.org/10.5194/esurf-5-67-2017, 2017
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Beryllium-10 is a rare isotope that only forms near to the Earth surface, allowing rock surfaces to be dated. In this paper we develop a numerical model for the evolution of shore platforms and associated 10Be concentrations to explore the potential for this method to reveal long-term rates of sea cliff retreat. Tides, sea level, cliffs and beaches all modify how rapidly 10Be accumulates on the shore platform, but there is great potential to measure rates of cliff retreat and platform erosion.
Amanda H. Schmidt, Thomas B. Neilson, Paul R. Bierman, Dylan H. Rood, William B. Ouimet, and Veronica Sosa Gonzalez
Earth Surf. Dynam., 4, 819–830, https://doi.org/10.5194/esurf-4-819-2016, https://doi.org/10.5194/esurf-4-819-2016, 2016
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In order to test the assumption that erosion rates derived from Be-10 are not affected by increases in erosion due to contemporary agricultural land use, we measured erosion rates in three tributaries of the Mekong River. We find that in the most heavily agricultural landscapes, the apparent long-term erosion rate correlates best with measures of modern land use, suggesting that agriculture has eroded below the mixed layer and is affecting apparent erosion rates derived from Be-10.
Tom Watts, Nick Rutter, Peter Toose, Chris Derksen, Melody Sandells, and John Woodward
The Cryosphere, 10, 2069–2074, https://doi.org/10.5194/tc-10-2069-2016, https://doi.org/10.5194/tc-10-2069-2016, 2016
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Ice layers in snowpacks introduce uncertainty in satellite-derived estimates of snow water equivalent, have ecological impacts on plants and animals, and change the thermal and vapour transport properties of the snowpack. Here we present a new field method for measuring the density of ice layers. The method was used in the Arctic and mid-latitudes; the mean measured ice layer density was significantly higher than values typically used in the literature.
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: Paleo-Glaciology (including Former Ice Reconstructions)
Millennial-scale fluctuations of palaeo-ice margin at the southern fringe of the last Fennoscandian Ice Sheet
The influence of glacial landscape evolution on Scandinavian ice-sheet dynamics and dimensions
Antarctic permafrost processes and antiphase dynamics of cold-based glaciers in the McMurdo Dry Valleys inferred from 10Be and 26Al cosmogenic nuclides
Simulating the Laurentide Ice Sheet of the Last Glacial Maximum
The collapse of the Cordilleran–Laurentide ice saddle and early opening of the Mackenzie Valley, Northwest Territories, Canada, constrained by 10Be exposure dating
A model for interaction between conduits and surrounding hydraulically connected distributed drainage based on geomorphological evidence from Keewatin, Canada
Repeated ice streaming on the northwest Greenland continental shelf since the onset of the Middle Pleistocene Transition
Nonlinear response of the Antarctic Ice Sheet to late Quaternary sea level and climate forcing
Eemian Greenland ice sheet simulated with a higher-order model shows strong sensitivity to surface mass balance forcing
The impact of model resolution on the simulated Holocene retreat of the southwestern Greenland ice sheet using the Ice Sheet System Model (ISSM)
Marine ice sheet instability and ice shelf buttressing of the Minch Ice Stream, northwest Scotland
Persistent tracers of historic ice flow in glacial stratigraphy near Kamb Ice Stream, West Antarctica
West Antarctic sites for subglacial drilling to test for past ice-sheet collapse
Karol Tylmann, Wojciech Wysota, Vincent Rinterknecht, Piotr Moska, Aleksandra Bielicka-Giełdoń, and ASTER Team
The Cryosphere, 18, 1889–1909, https://doi.org/10.5194/tc-18-1889-2024, https://doi.org/10.5194/tc-18-1889-2024, 2024
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Our results indicate millennial-scale oscillations of the last Fennoscandian Ice Sheet (FIS) in northern Poland between ~19000 and ~17000 years ago. Combined luminescence (OSL) and 10Be dating show the last FIS left basal tills of three ice re-advances at a millennial-scale cycle: 19.2 ± 1.1 ka, 17.8 ± 0.5 ka and 16.9 ± 0.5 ka. This is the first terrestrial record of millennial-scale palaeo-ice margin oscillations at the southern fringe of the FIS during the last glacial cycle.
Gustav Jungdal-Olesen, Jane Lund Andersen, Andreas Born, and Vivi Kathrine Pedersen
The Cryosphere, 18, 1517–1532, https://doi.org/10.5194/tc-18-1517-2024, https://doi.org/10.5194/tc-18-1517-2024, 2024
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We explore how the shape of the land and underwater features in Scandinavia affected the former Scandinavian ice sheet over time. Using a computer model, we simulate how the ice sheet evolved during different stages of landscape development. We discovered that early glaciations were limited in size by underwater landforms, but as these changed, the ice sheet expanded more rapidly. Our findings highlight the importance of considering landscape changes when studying ice-sheet history.
Jacob T. H. Anderson, Toshiyuki Fujioka, David Fink, Alan J. Hidy, Gary S. Wilson, Klaus Wilcken, Andrey Abramov, and Nikita Demidov
The Cryosphere, 17, 4917–4936, https://doi.org/10.5194/tc-17-4917-2023, https://doi.org/10.5194/tc-17-4917-2023, 2023
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Antarctic permafrost processes are not widely studied or understood in the McMurdo Dry Valleys. Our data show that near-surface permafrost sediments were deposited ~180 000 years ago in Pearse Valley, while in lower Wright Valley sediments are either vertically mixed after deposition or were deposited < 25 000 years ago. Our data also record Taylor Glacier retreat from Pearse Valley ~65 000–74 000 years ago and support antiphase dynamics between alpine glaciers and sea ice in the Ross Sea.
Daniel Moreno-Parada, Jorge Alvarez-Solas, Javier Blasco, Marisa Montoya, and Alexander Robinson
The Cryosphere, 17, 2139–2156, https://doi.org/10.5194/tc-17-2139-2023, https://doi.org/10.5194/tc-17-2139-2023, 2023
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We have reconstructed the Laurentide Ice Sheet, located in North America during the Last Glacial Maximum (21 000 years ago). The absence of direct measurements raises a number of uncertainties. Here we study the impact of different physical laws that describe the friction as the ice slides over its base. We found that the Laurentide Ice Sheet is closest to prior reconstructions when the basal friction takes into account whether the base is frozen or thawed during its motion.
Benjamin J. Stoker, Martin Margold, John C. Gosse, Alan J. Hidy, Alistair J. Monteath, Joseph M. Young, Niall Gandy, Lauren J. Gregoire, Sophie L. Norris, and Duane Froese
The Cryosphere, 16, 4865–4886, https://doi.org/10.5194/tc-16-4865-2022, https://doi.org/10.5194/tc-16-4865-2022, 2022
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The Laurentide Ice Sheet was the largest ice sheet to grow and disappear in the Northern Hemisphere during the last glaciation. In northwestern Canada, it covered the Mackenzie Valley, blocking the migration of fauna and early humans between North America and Beringia and altering the drainage systems. We reconstruct the timing of ice sheet retreat in this region and the implications for the migration of early humans into North America, the drainage of glacial lakes, and past sea level rise.
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.
Andrew M. W. Newton, Mads Huuse, Paul C. Knutz, and David R. Cox
The Cryosphere, 14, 2303–2312, https://doi.org/10.5194/tc-14-2303-2020, https://doi.org/10.5194/tc-14-2303-2020, 2020
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Seismic reflection data offshore northwest Greenland reveal buried landforms that have been interpreted as mega-scale glacial lineations (MSGLs). These have been formed by ancient ice streams that advanced hundreds of kilometres across the continental shelf. The stratigraphy and available chronology show that the MSGLs are confined to separate stratigraphic units and were most likely formed during several glacial maxima after the onset of the Middle Pleistocene Transition at ~ 1.3 Ma.
Michelle Tigchelaar, Axel Timmermann, Tobias Friedrich, Malte Heinemann, and David Pollard
The Cryosphere, 13, 2615–2631, https://doi.org/10.5194/tc-13-2615-2019, https://doi.org/10.5194/tc-13-2615-2019, 2019
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The Antarctic Ice Sheet has expanded and retracted often in the past, but, so far, studies have not identified which environmental driver is most important: air temperature, snowfall, ocean conditions or global sea level. In a modeling study of 400 000 years of Antarctic Ice Sheet variability we isolated different drivers and found that no single driver dominates. Air temperature and sea level are most important and combine in a synergistic way, with important implications for future change.
Andreas Plach, Kerim H. Nisancioglu, Petra M. Langebroek, Andreas Born, and Sébastien Le clec'h
The Cryosphere, 13, 2133–2148, https://doi.org/10.5194/tc-13-2133-2019, https://doi.org/10.5194/tc-13-2133-2019, 2019
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Meltwater from the Greenland ice sheet (GrIS) rises sea level and knowing how the GrIS behaved in the past will help to become better in predicting its future. Here, the evolution of the past GrIS is shown to be dominated by how much ice melts (a result of the prevailing climate) rather than how ice flow is represented in the simulations. Therefore, it is very important to know past climates accurately, in order to be able to simulate the evolution of the GrIS and its contribution to sea level.
Joshua K. Cuzzone, Nicole-Jeanne Schlegel, Mathieu Morlighem, Eric Larour, Jason P. Briner, Helene Seroussi, and Lambert Caron
The Cryosphere, 13, 879–893, https://doi.org/10.5194/tc-13-879-2019, https://doi.org/10.5194/tc-13-879-2019, 2019
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We present ice sheet modeling results of ice retreat over southwestern Greenland during the last 12 000 years, and we also test the impact that model horizontal resolution has on differences in the simulated spatial retreat and its associated rate. Results indicate that model resolution plays a minor role in simulated retreat in areas where bed topography is not complex but plays an important role in areas where bed topography is complex (such as fjords).
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.
Nicholas Holschuh, Knut Christianson, Howard Conway, Robert W. Jacobel, and Brian C. Welch
The Cryosphere, 12, 2821–2829, https://doi.org/10.5194/tc-12-2821-2018, https://doi.org/10.5194/tc-12-2821-2018, 2018
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Models of the Antarctic Sheet are tuned using observations of historic ice-sheet behavior, but we have few observations that tell us how inland ice behaved over the last few millennia. A 2 km tall volcano sitting under the ice sheet has left a record in the ice as it flows by, and that feature provides unique insight into the regional ice-flow history. It indicates that observed, rapid changes in West Antarctica flow dynamics have not affected the continental interior over the last 5700 years.
Perry Spector, John Stone, David Pollard, Trevor Hillebrand, Cameron Lewis, and Joel Gombiner
The Cryosphere, 12, 2741–2757, https://doi.org/10.5194/tc-12-2741-2018, https://doi.org/10.5194/tc-12-2741-2018, 2018
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Cosmogenic-nuclide analyses in bedrock recovered from below the West Antarctic Ice Sheet have the potential to establish whether and when large-scale deglaciation occurred in the past. Here we (i) discuss the criteria and considerations for subglacial drill sites, (ii) evaluate candidate sites in West Antarctica, and (iii) describe reconnaissance at three West Antarctic sites, focusing on the Pirrit Hills, which we present as a case study of site selection on the scale of an individual nunatak.
Cited articles
Adams, J. R., Johnson, J. S., Roberts, S. J., Mason, P. J., Nichols, K. A., Venturelli, R. A., Wilcken, K., Balco, G., Goehring, B., Hall, B., Woodward, J., and Rood, D. H.: New 10Be exposure ages improve Holocene ice sheet thinning history near the grounding line of Pope Glacier, Antarctica, The Cryosphere, 16, 4887–4905, https://doi.org/10.5194/tc-16-4887-2022, 2022. a, b, c
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Co-editor-in-chief
In recent years there has been growing concern about the potentially irreversible retreat of the West Antarctic Ice Sheet and Thwaites Glacier in particular causing deglaciation of large parts of the ice sheet and leading to substantial sea-level rise. This study demonstrates that a site between Thwaites and Pope glaciers has undergone ice-sheet thinning and subsequent thickening in the past. The results are of importance for a better understanding of future threats to the stability of the West Antarctic ice sheet, and the ice-sheet evolution in the Amundsen sector over the late Holocene.
In recent years there has been growing concern about the potentially irreversible retreat of the...
Short summary
Samples of bedrock recovered from below the West Antarctic Ice Sheet show that part of the ice sheet was thinner several thousand years ago than it is now and subsequently thickened. This is important because of concern that present ice thinning in this region may lead to rapid, irreversible sea level rise. The past episode of thinning at this site that took place in a similar, although not identical, climate was not irreversible; however, reversal required at least 3000 years to complete.
Samples of bedrock recovered from below the West Antarctic Ice Sheet show that part of the ice...
