Articles | Volume 18, issue 9
https://doi.org/10.5194/tc-18-4029-2024
© Author(s) 2024. 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-18-4029-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
05 Sep 2024
Research article |
| 05 Sep 2024
| 05 Sep 2024
Scientific history, sampling approach, and physical characterization of the Camp Century subglacial material, a rare archive from beneath the Greenland Ice Sheet
Rubenstein School of the Environment and Natural Resources, University of Vermont, Burlington, VT 05401, USA
Gund Institute for Environment, University of Vermont, Burlington, VT 05401, USA
Andrew J. Christ
Rubenstein School of the Environment and Natural Resources, University of Vermont, Burlington, VT 05401, USA
currently at: U.S. Reinsurance Analytics, Aon plc, Denver, CO 80206, USA
Catherine M. Collins
Rubenstein School of the Environment and Natural Resources, University of Vermont, Burlington, VT 05401, USA
Gund Institute for Environment, University of Vermont, Burlington, VT 05401, USA
Halley M. Mastro
Rubenstein School of the Environment and Natural Resources, University of Vermont, Burlington, VT 05401, USA
Gund Institute for Environment, University of Vermont, Burlington, VT 05401, USA
Juliana Souza
Rubenstein School of the Environment and Natural Resources, University of Vermont, Burlington, VT 05401, USA
Gund Institute for Environment, University of Vermont, Burlington, VT 05401, USA
Pierre-Henri Blard
Centre de Recherches Pétrographiques et Géochimiques, CNRS, Université de Lorraine, 54500 Nancy, France
Laboratoire de Glaciologie, Université Libre de Bruxelles, 1050 Brussels, Belgium
Stefanie Brachfeld
Earth and Environmental Studies, Montclair State University, Montclair, NJ 07043, USA
Zoe R. Courville
U.S. Army Corps of Engineers Cold Regions Research and Engineering Laboratory, Hanover, NH 03755, USA
Tammy M. Rittenour
Department of Geosciences, Utah State University, Logan, UT 84322, USA
Elizabeth K. Thomas
Department of Geology, University at Buffalo, Buffalo, NY 14260, USA
Jean-Louis Tison
Laboratoire de Glaciologie, Université Libre de Bruxelles, 1050 Brussels, Belgium
François Fripiat
Laboratoire de Glaciologie, Université Libre de Bruxelles, 1050 Brussels, Belgium
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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.
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To investigate the Laurentide Ice Sheet’s erosivity before and during the Last Glacial Maximum, we sampled sand deposited by ice in eastern Canada before final deglaciation. We also sampled modern river sand. The 26Al and 10Be measured in glacial deposited sediments suggests that ice remained during some Pleistocene warm periods and was an inefficient eroder. Similar concentrations of 26Al and 10Be in modern sand suggests that most modern river sediment is sourced from glacial deposits.
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The Camp Century sub-glacial core stores information about past climates, glacial and interglacial processes in northwest Greenland. In this study, we investigated the core archive making large scale observations using CT scans and micron scale observation observing physical and chemical characteristics of individual grains. We find evidence of past ice-free conditions, weathering processes during warmer periods, and past glaciations.
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New exposure ages of glacial erratics on moraines on Isle Royale – the largest island in North America's Lake Superior – show that the Laurentide Ice Sheet did not retreat from the island nor the south shores of Lake Superior until the early Holocene, which is later than previously thought. These new ages unify regional ice retreat histories from the mainland, the Lake Superior lake-bottom stratigraphy, underwater moraines, and meltwater drainage pathways through the Laurentian Great Lakes.
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To understand landscape evolution in the mineral resource-rich Yukon River basin (Alaska and Canada), we mapped and cosmogenic isotope-dated river terraces along the Charley River. Results imply widespread Yukon River incision that drove increased Bering Sea sedimentation and carbon sequestration during global climate changes 2.6 and 1 million years ago. Such erosion may have fed back to late Cenozoic climate change by reducing atmospheric carbon as observed in many records worldwide.
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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.
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Christopher Halsted, Paul Bierman, Alexandru Codilean, Lee Corbett, and Marc Caffee
Geochronology Discuss., https://doi.org/10.5194/gchron-2024-22, https://doi.org/10.5194/gchron-2024-22, 2024
Preprint under review for GChron
Short summary
Short summary
Sediment generation on hillslopes and transport through river networks are complex processes that influence landscape evolution. In this study compiled sand from over 600 river basins and measured its (very subtle) radioactivity to unravel timelines of sediment routing around the world. With this data we empirically confirm that sediment from large lowland basins in tectonically stable regions typically experiences long periods of burial, while sediment moves rapidly through small upland basins.
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.
Peyton M. Cavnar, Paul R. Bierman, Jeremy D. Shakun, Lee B. Corbett, Danielle LeBlanc, Gillian L. Galford, and Marc Caffee
EGUsphere, https://doi.org/10.5194/egusphere-2024-2233, https://doi.org/10.5194/egusphere-2024-2233, 2024
Short summary
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To investigate the Laurentide Ice Sheet’s erosivity before and during the Last Glacial Maximum, we sampled sand deposited by ice in eastern Canada before final deglaciation. We also sampled modern river sand. The 26Al and 10Be measured in glacial deposited sediments suggests that ice remained during some Pleistocene warm periods and was an inefficient eroder. Similar concentrations of 26Al and 10Be in modern sand suggests that most modern river sediment is sourced from glacial deposits.
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Catherine M. Collins, Nicolas Perdrial, Pierre-Henri Blard, Nynke Keulen, William C. Mahaney, Halley Mastro, Juliana Souza, Donna M. Rizzo, Yves Marrocchi, Paul C. Knutz, and Paul R. Bierman
EGUsphere, https://doi.org/10.5194/egusphere-2024-2194, https://doi.org/10.5194/egusphere-2024-2194, 2024
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The Camp Century sub-glacial core stores information about past climates, glacial and interglacial processes in northwest Greenland. In this study, we investigated the core archive making large scale observations using CT scans and micron scale observation observing physical and chemical characteristics of individual grains. We find evidence of past ice-free conditions, weathering processes during warmer periods, and past glaciations.
Pedro Doll, Shaun Robert Eaves, Ben Matthew Kennedy, Pierre-Henri Blard, Alexander Robert Lee Nichols, Graham Sloan Leonard, Dougal Bruce Townsend, Jim William Cole, Chris Edward Conway, Sacha Baldwin, Gabriel Fénisse, Laurent Zimmermann, and Bouchaïb Tibari
Geochronology, 6, 365–395, https://doi.org/10.5194/gchron-6-365-2024, https://doi.org/10.5194/gchron-6-365-2024, 2024
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In this study, we use cosmogenic-sourced 3He to determine the eruption ages of 23 lava flows at Mt Ruapehu, Aotearoa New Zealand, and we show how this method can help overcome challenges associated with traditional dating methods in young lavas. Comparison with other methods demonstrates the accuracy of our data and the method's reliability. The new eruption ages allowed us to identify periods of quasi-simultaneous activity from different volcanic vents during the last 20 000 years.
Sarah Wauthy, Jean-Louis Tison, Mana Inoue, Saïda El Amri, Sainan Sun, François Fripiat, Philippe Claeys, and Frank Pattyn
Earth Syst. Sci. Data, 16, 35–58, https://doi.org/10.5194/essd-16-35-2024, https://doi.org/10.5194/essd-16-35-2024, 2024
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The datasets presented are the density, water isotopes, ions, and conductivity measurements, as well as age models and surface mass balance (SMB) from the top 120 m of two ice cores drilled on adjacent ice rises in Dronning Maud Land, dating from the late 18th century. They offer many development possibilities for the interpretation of paleo-profiles and for addressing the mechanisms behind the spatial and temporal variability of SMB and proxies observed at the regional scale in East Antarctica.
Eric W. Portenga, David J. Ullman, Lee B. Corbett, Paul R. Bierman, and Marc W. Caffee
Geochronology, 5, 413–431, https://doi.org/10.5194/gchron-5-413-2023, https://doi.org/10.5194/gchron-5-413-2023, 2023
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New exposure ages of glacial erratics on moraines on Isle Royale – the largest island in North America's Lake Superior – show that the Laurentide Ice Sheet did not retreat from the island nor the south shores of Lake Superior until the early Holocene, which is later than previously thought. These new ages unify regional ice retreat histories from the mainland, the Lake Superior lake-bottom stratigraphy, underwater moraines, and meltwater drainage pathways through the Laurentian Great Lakes.
Weiyi Tang, Bess B. Ward, Michael Beman, Laura Bristow, Darren Clark, Sarah Fawcett, Claudia Frey, François Fripiat, Gerhard J. Herndl, Mhlangabezi Mdutyana, Fabien Paulot, Xuefeng Peng, Alyson E. Santoro, Takuhei Shiozaki, Eva Sintes, Charles Stock, Xin Sun, Xianhui S. Wan, Min N. Xu, and Yao Zhang
Earth Syst. Sci. Data, 15, 5039–5077, https://doi.org/10.5194/essd-15-5039-2023, https://doi.org/10.5194/essd-15-5039-2023, 2023
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Nitrification and nitrifiers play an important role in marine nitrogen and carbon cycles by converting ammonium to nitrite and nitrate. Nitrification could affect microbial community structure, marine productivity, and the production of nitrous oxide – a powerful greenhouse gas. We introduce the newly constructed database of nitrification and nitrifiers in the marine water column and guide future research efforts in field observations and model development of nitrification.
Marie G. P. Cavitte, Hugues Goosse, Kenichi Matsuoka, Sarah Wauthy, Vikram Goel, Rahul Dey, Bhanu Pratap, Brice Van Liefferinge, Thamban Meloth, and Jean-Louis Tison
The Cryosphere, 17, 4779–4795, https://doi.org/10.5194/tc-17-4779-2023, https://doi.org/10.5194/tc-17-4779-2023, 2023
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The net accumulation of snow over Antarctica is key for assessing current and future sea-level rise. Ice cores record a noisy snowfall signal to verify model simulations. We find that ice core net snowfall is biased to lower values for ice rises and the Dome Fuji site (Antarctica), while the relative uncertainty in measuring snowfall increases rapidly with distance away from the ice core sites at the ice rises but not at Dome Fuji. Spatial variation in snowfall must therefore be considered.
Brandon L. Graham, Jason P. Briner, Nicolás E. Young, Allie Balter-Kennedy, Michele Koppes, Joerg M. Schaefer, Kristin Poinar, and Elizabeth K. Thomas
The Cryosphere, 17, 4535–4547, https://doi.org/10.5194/tc-17-4535-2023, https://doi.org/10.5194/tc-17-4535-2023, 2023
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Glacial erosion is a fundamental process operating on Earth's surface. Two processes of glacial erosion, abrasion and plucking, are poorly understood. We reconstructed rates of abrasion and quarrying in Greenland. We derive a total glacial erosion rate of 0.26 ± 0.16 mm per year. We also learned that erosion via these two processes is about equal. Because the site is similar to many other areas covered by continental ice sheets, these results may be applied to many places on Earth.
Adrian M. Bender, Richard O. Lease, Lee B. Corbett, Paul R. Bierman, Marc W. Caffee, James V. Jones, and Doug Kreiner
Earth Surf. Dynam., 10, 1041–1053, https://doi.org/10.5194/esurf-10-1041-2022, https://doi.org/10.5194/esurf-10-1041-2022, 2022
Short summary
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To understand landscape evolution in the mineral resource-rich Yukon River basin (Alaska and Canada), we mapped and cosmogenic isotope-dated river terraces along the Charley River. Results imply widespread Yukon River incision that drove increased Bering Sea sedimentation and carbon sequestration during global climate changes 2.6 and 1 million years ago. Such erosion may have fed back to late Cenozoic climate change by reducing atmospheric carbon as observed in many records worldwide.
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.
Agathe Defourny, Pierre-Henri Blard, Laurent Zimmermann, Patrick Jobé, Arnaud Collignon, Frédéric Nguyen, and Alain Dassargues
Hydrol. Earth Syst. Sci., 26, 2637–2648, https://doi.org/10.5194/hess-26-2637-2022, https://doi.org/10.5194/hess-26-2637-2022, 2022
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The Belgian city of Spa is known worldwide for its ferruginous and naturally sparkling groundwater springs that gave their name to the bathing tradition commonly called
spa. However, the origin of the dissolved CO2 they contain was still a matter of debate. Thanks to new analysis on groundwater samples, particularly carbon and helium isotopes together with dissolved gases, this study has demonstrated that the volcanic origin of the CO2 is presumably from the neighboring Eifel volcanic fields.
Leah A. VanLandingham, Eric W. Portenga, Edward C. Lefroy, Amanda H. Schmidt, Paul R. Bierman, and Alan J. Hidy
Geochronology, 4, 153–176, https://doi.org/10.5194/gchron-4-153-2022, https://doi.org/10.5194/gchron-4-153-2022, 2022
Short summary
Short summary
This study presents erosion rates of the George River and seven of its tributaries in northeast Tasmania, Australia. These erosion rates are the first measures of landscape change over millennial timescales for Tasmania. We demonstrate that erosion is closely linked to a topographic rainfall gradient across George River. Our findings may be useful for efforts to restore ecological health to Georges Bay by determining a pre-disturbance level of erosion and sediment delivery to this estuary.
Andrew J. Christ, Paul R. Bierman, Jennifer L. Lamp, Joerg M. Schaefer, and Gisela Winckler
Geochronology, 3, 505–523, https://doi.org/10.5194/gchron-3-505-2021, https://doi.org/10.5194/gchron-3-505-2021, 2021
Short summary
Short summary
Cosmogenic nuclide surface exposure dating is commonly used to constrain the timing of past glacier extents. However, Antarctic exposure age datasets are often scattered and difficult to interpret. We compile new and existing exposure ages of a glacial deposit with independently known age constraints and identify surface processes that increase or reduce the likelihood of exposure age scatter. Then we present new data for a previously unmapped and undated older deposit from the same region.
Melisa A. Diaz, Lee B. Corbett, Paul R. Bierman, Byron J. Adams, Diana H. Wall, Ian D. Hogg, Noah Fierer, and W. Berry Lyons
Earth Surf. Dynam., 9, 1363–1380, https://doi.org/10.5194/esurf-9-1363-2021, https://doi.org/10.5194/esurf-9-1363-2021, 2021
Short summary
Short summary
We collected soil surface samples and depth profiles every 5 cm (up to 30 cm) from 11 ice-free areas along the Shackleton Glacier, a major outlet glacier of the East Antarctic Ice Sheet (EAIS), and measured meteoric beryllium-10 and nitrate concentrations to understand the relationship between salts and beryllium-10. This relationship can help inform wetting history, landscape disturbance, and exposure duration.
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
Short summary
Short summary
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.
Thore Kausch, Stef Lhermitte, Jan T. M. Lenaerts, Nander Wever, Mana Inoue, Frank Pattyn, Sainan Sun, Sarah Wauthy, Jean-Louis Tison, and Willem Jan van de Berg
The Cryosphere, 14, 3367–3380, https://doi.org/10.5194/tc-14-3367-2020, https://doi.org/10.5194/tc-14-3367-2020, 2020
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Ice rises are elevated parts of the otherwise flat ice shelf. Here we study the impact of an Antarctic ice rise on the surrounding snow accumulation by combining field data and modeling. Our results show a clear difference in average yearly snow accumulation between the windward side, the leeward side and the peak of the ice rise due to differences in snowfall and wind erosion. This is relevant for the interpretation of ice core records, which are often drilled on the peak of an ice rise.
Bronwen L. Konecky, Nicholas P. McKay, Olga V. Churakova (Sidorova), Laia Comas-Bru, Emilie P. Dassié, Kristine L. DeLong, Georgina M. Falster, Matt J. Fischer, Matthew D. Jones, Lukas Jonkers, Darrell S. Kaufman, Guillaume Leduc, Shreyas R. Managave, Belen Martrat, Thomas Opel, Anais J. Orsi, Judson W. Partin, Hussein R. Sayani, Elizabeth K. Thomas, Diane M. Thompson, Jonathan J. Tyler, Nerilie J. Abram, Alyssa R. Atwood, Olivier Cartapanis, Jessica L. Conroy, Mark A. Curran, Sylvia G. Dee, Michael Deininger, Dmitry V. Divine, Zoltán Kern, Trevor J. Porter, Samantha L. Stevenson, Lucien von Gunten, and Iso2k Project Members
Earth Syst. Sci. Data, 12, 2261–2288, https://doi.org/10.5194/essd-12-2261-2020, https://doi.org/10.5194/essd-12-2261-2020, 2020
Hannah S. Weiss, Paul R. Bierman, Yves Dubief, and Scott D. Hamshaw
The Cryosphere, 13, 3367–3382, https://doi.org/10.5194/tc-13-3367-2019, https://doi.org/10.5194/tc-13-3367-2019, 2019
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Climate change is devastating winter tourism. High-elevation, high-latitude ski centers have turned to saving snow over the summer. We present results of two field seasons to test and optimize over-summer snow storage at a midlatitude, low-elevation nordic ski center in the northeastern USA. In 2018, we tested coverings and found success overlaying 20 cm of wet woodchips with a reflective sheet. In 2019, we employed this strategy to a large pile and stored sufficient snow to open the ski season.
Hans W. Linderholm, Marie Nicolle, Pierre Francus, Konrad Gajewski, Samuli Helama, Atte Korhola, Olga Solomina, Zicheng Yu, Peng Zhang, William J. D'Andrea, Maxime Debret, Dmitry V. Divine, Björn E. Gunnarson, Neil J. Loader, Nicolas Massei, Kristina Seftigen, Elizabeth K. Thomas, Johannes Werner, Sofia Andersson, Annika Berntsson, Tomi P. Luoto, Liisa Nevalainen, Saija Saarni, and Minna Väliranta
Clim. Past, 14, 473–514, https://doi.org/10.5194/cp-14-473-2018, https://doi.org/10.5194/cp-14-473-2018, 2018
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This paper reviews the current knowledge of Arctic hydroclimate variability during the past 2000 years. We discuss the current state, look into the future, and describe various archives and proxies used to infer past hydroclimate variability. We also provide regional overviews and discuss the potential of furthering our understanding of Arctic hydroclimate in the past. This paper summarises the hydroclimate-related activities of the Arctic 2k group.
Goulven G. Laruelle, Peter Landschützer, Nicolas Gruber, Jean-Louis Tison, Bruno Delille, and Pierre Regnier
Biogeosciences, 14, 4545–4561, https://doi.org/10.5194/bg-14-4545-2017, https://doi.org/10.5194/bg-14-4545-2017, 2017
Célia J. Sapart, Natalia Shakhova, Igor Semiletov, Joachim Jansen, Sönke Szidat, Denis Kosmach, Oleg Dudarev, Carina van der Veen, Matthias Egger, Valentine Sergienko, Anatoly Salyuk, Vladimir Tumskoy, Jean-Louis Tison, and Thomas Röckmann
Biogeosciences, 14, 2283–2292, https://doi.org/10.5194/bg-14-2283-2017, https://doi.org/10.5194/bg-14-2283-2017, 2017
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The Arctic Ocean, especially the Siberian shelves, overlays large areas of subsea permafrost that is degrading. We show that methane with a biogenic origin is emitted from this permafrost. At locations where bubble plumes have been observed, methane can escape oxidation in the surface sediment and rapidly migrate through the very shallow water column of this region to escape to the atmosphere, generating a positive radiative feedback.
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.
Morgane Philippe, Jean-Louis Tison, Karen Fjøsne, Bryn Hubbard, Helle A. Kjær, Jan T. M. Lenaerts, Reinhard Drews, Simon G. Sheldon, Kevin De Bondt, Philippe Claeys, and Frank Pattyn
The Cryosphere, 10, 2501–2516, https://doi.org/10.5194/tc-10-2501-2016, https://doi.org/10.5194/tc-10-2501-2016, 2016
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The reconstruction of past snow accumulation rates is crucial in the context of recent climate change and sea level rise. We measured ~ 250 years of snow accumulation using a 120 m ice core drilled in coastal East Antarctica, where such long records are very scarce. This study is the first to show an increase in snow accumulation, beginning in the 20th and particularly marked in the last 50 years, thereby confirming model predictions of increased snowfall associated with climate change.
Odile Crabeck, Ryan Galley, Bruno Delille, Brent Else, Nicolas-Xavier Geilfus, Marcos Lemes, Mathieu Des Roches, Pierre Francus, Jean-Louis Tison, and Søren Rysgaard
The Cryosphere, 10, 1125–1145, https://doi.org/10.5194/tc-10-1125-2016, https://doi.org/10.5194/tc-10-1125-2016, 2016
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We present a new non-destructive X-ray-computed tomography technique to quantify the air volume fraction and produce separate 3-D images of air-volume inclusions in sea ice. While the internal layers showed air-volume fractions < 2 %, the ice–air interface (top 2 cm) showed values up to 5 %. As a result of the presence of large bubbles and higher air volume fraction measurements in sea ice, we introduce new perspectives on processes regulating gas exchange at the ice–atmosphere interface.
Thomas Goossens, Célia J. Sapart, Dorthe Dahl-Jensen, Trevor Popp, Saïda El Amri, and Jean-Louis Tison
The Cryosphere, 10, 553–567, https://doi.org/10.5194/tc-10-553-2016, https://doi.org/10.5194/tc-10-553-2016, 2016
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This first multi-parametric analysis of the basal ice layer of the NEEM ice core reveals that its formation does not result from a mixing process between local relict ice and the deepest ice layers of the advancing ice sheet during its growth phase. Instead, it is shown that the basal sequence partly originates from melting and refreezing processes acting at the ice/bedrock interface under a well-developed ice sheet. These have partially destroyed the paleoclimatic records of the ice.
J.-L. Tison, M. de Angelis, G. Littot, E. Wolff, H. Fischer, M. Hansson, M. Bigler, R. Udisti, A. Wegner, J. Jouzel, B. Stenni, S. Johnsen, V. Masson-Delmotte, A. Landais, V. Lipenkov, L. Loulergue, J.-M. Barnola, J.-R. Petit, B. Delmonte, G. Dreyfus, D. Dahl-Jensen, G. Durand, B. Bereiter, A. Schilt, R. Spahni, K. Pol, R. Lorrain, R. Souchez, and D. Samyn
The Cryosphere, 9, 1633–1648, https://doi.org/10.5194/tc-9-1633-2015, https://doi.org/10.5194/tc-9-1633-2015, 2015
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The oldest paleoclimatic information is buried within the lowermost layers of deep ice cores. It is therefore essential to judge how deep these records remain unaltered. We study the bottom 60 meters of the EPICA Dome C ice core from central Antarctica to show that the paleoclimatic signal is only affected at the small scale (decimeters) in terms of some of the global ice properties. However our data suggest that the time scale has been considerably distorted by mechanical stretching.
N.-X. Geilfus, R. J. Galley, O. Crabeck, T. Papakyriakou, J. Landy, J.-L. Tison, and S. Rysgaard
Biogeosciences, 12, 2047–2061, https://doi.org/10.5194/bg-12-2047-2015, https://doi.org/10.5194/bg-12-2047-2015, 2015
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We investigated the evolution of inorganic carbon within landfast sea ice in Resolute Passage during the spring and summer melt period.
Low TA and TCO2 concentrations observed in sea ice and brine were associated with the percolation of meltwater from melt ponds. Meltwater was continuously supplied to the ponds which prevented melt ponds from fully equilibrating with the atmospheric CO2 concentration, promoting a continuous uptake of CO2 from the atmosphere.
N.-X. Geilfus, J.-L. Tison, S. F. Ackley, R. J. Galley, S. Rysgaard, L. A. Miller, and B. Delille
The Cryosphere, 8, 2395–2407, https://doi.org/10.5194/tc-8-2395-2014, https://doi.org/10.5194/tc-8-2395-2014, 2014
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Temporal evolution of pCO2 profiles in sea ice in the Bellingshausen Sea, Antarctica (Oct. 2007), shows that physical and thermodynamic processes control the CO2 system in the ice. We show that each cooling/warming event was associated with an increase/decrease in the brine salinity, TA, TCO2, and in situ brine and bulk ice pCO2. Thicker snow covers reduced the amplitude of these changes. Both brine and bulk ice pCO2 were undersaturated, causing the sea ice to act as a sink for atmospheric CO2.
O. Crabeck, B. Delille, D. Thomas, N.-X. Geilfus, S. Rysgaard, and J.-L. Tison
Biogeosciences, 11, 6525–6538, https://doi.org/10.5194/bg-11-6525-2014, https://doi.org/10.5194/bg-11-6525-2014, 2014
J. Zhou, B. Delille, F. Brabant, and J.-L. Tison
Biogeosciences, 11, 5007–5020, https://doi.org/10.5194/bg-11-5007-2014, https://doi.org/10.5194/bg-11-5007-2014, 2014
J. Zhou, J.-L. Tison, G. Carnat, N.-X. Geilfus, and B. Delille
The Cryosphere, 8, 1019–1029, https://doi.org/10.5194/tc-8-1019-2014, https://doi.org/10.5194/tc-8-1019-2014, 2014
L. L. Sørensen, B. Jensen, R. N. Glud, D. F. McGinnis, M. K. Sejr, J. Sievers, D. H. Søgaard, J.-L. Tison, and S. Rysgaard
The Cryosphere, 8, 853–866, https://doi.org/10.5194/tc-8-853-2014, https://doi.org/10.5194/tc-8-853-2014, 2014
M. Vancoppenolle, D. Notz, F. Vivier, J. Tison, B. Delille, G. Carnat, J. Zhou, F. Jardon, P. Griewank, A. Lourenço, and T. Haskell
The Cryosphere Discuss., https://doi.org/10.5194/tcd-7-3209-2013, https://doi.org/10.5194/tcd-7-3209-2013, 2013
Revised manuscript not accepted
Related subject area
Discipline: Ice sheets | Subject: Ice Cores
Laser ablation inductively coupled plasma mass spectrometry measurements for high-resolution chemical ice core analyses with a first application to an ice core from Skytrain Ice Rise (Antarctica)
The grain-scale signature of isotopic diffusion in ice
Combining traditional and novel techniques to increase our understanding of the lock-in depth of atmospheric gases in polar ice cores – results from the EastGRIP region
Novel approach to estimate the water isotope diffusion length in deep ice cores with an application to Marine Isotope Stage 19 in the Dome C ice core
The potential of in situ cosmogenic 14CO in ice cores as a proxy for galactic cosmic ray flux variations
Characterization of in situ cosmogenic 14CO production, retention and loss in firn and shallow ice at Summit, Greenland
Research into mechanical modeling based on characteristics of the fracture mechanics of ice cutting for scientific drilling in polar regions
Millennial and orbital-scale variability in a 54 000-year record of total air content from the South Pole ice core
Investigating the spatial representativeness of East Antarctic ice cores: a comparison of ice core and radar-derived surface mass balance over coastal ice rises and Dome Fuji
Greenland and Canadian Arctic ice temperature profiles database
Isotopic diffusion in ice enhanced by vein-water flow
A one-dimensional temperature and age modeling study for selecting the drill site of the oldest ice core near Dome Fuji, Antarctica
Chemical and visual characterisation of EGRIP glacial ice and cloudy bands within
Detection of ice core particles via deep neural networks
Development of crystal orientation fabric in the Dome Fuji ice core in East Antarctica: implications for the deformation regime in ice sheets
Gas isotope thermometry in the South Pole and Dome Fuji ice cores provides evidence for seasonal rectification of ice core gas records
Microstructure, micro-inclusions, and mineralogy along the EGRIP (East Greenland Ice Core Project) ice core – Part 2: Implications for palaeo-mineralogy
Microstructure, micro-inclusions, and mineralogy along the EGRIP ice core – Part 1: Localisation of inclusions and deformation patterns
Fractionation of O2∕N2 and Ar∕N2 in the Antarctic ice sheet during bubble formation and bubble–clathrate hydrate transition from precise gas measurements of the Dome Fuji ice core
Two-dimensional impurity imaging in deep Antarctic ice cores: snapshots of three climatic periods and implications for high-resolution signal interpretation
Brief communication: New radar constraints support presence of ice older than 1.5 Myr at Little Dome C
Pervasive diffusion of climate signals recorded in ice-vein ionic impurities
Multi-tracer study of gas trapping in an East Antarctic ice core
Very old firn air linked to strong density layering at Styx Glacier, coastal Victoria Land, East Antarctica
Glaciological characteristics in the Dome Fuji region and new assessment for “Oldest Ice”
Helene Hoffmann, Jason Day, Rachael H. Rhodes, Mackenzie Grieman, Jack Humby, Isobel Rowell, Christoph Nehrbass-Ahles, Robert Mulvaney, Sally Gibson, and Eric Wolff
The Cryosphere, 18, 4993–5013, https://doi.org/10.5194/tc-18-4993-2024, https://doi.org/10.5194/tc-18-4993-2024, 2024
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Ice cores are archives of past atmospheric conditions. In deep and old ice, the layers containing this information get thinned to the millimetre scale or below. We installed a setup for high-resolution (182 μm) chemical impurity measurements in ice cores using the laser ablation technique at the University of Cambridge. In a first application to the Skytrain ice core from Antarctica, we discuss the potential to detect fine-layered structures in ice up to an age of 26 000 years.
Felix S. L. Ng
The Cryosphere, 18, 4645–4669, https://doi.org/10.5194/tc-18-4645-2024, https://doi.org/10.5194/tc-18-4645-2024, 2024
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Liquid veins and grain boundaries in ice can accelerate the decay of climate signals in δ18O and δD by short-circuiting the slow isotopic diffusion in crystal grains. This theory for "excess diffusion" has not been confirmed experimentally. We show that, if the mechanism occurs, then distinct isotopic patterns must form near grain junctions, offering a testable prediction of the theory. We calculate the patterns and describe an experimental scheme for testing ice-core samples for the mechanism.
Julien Westhoff, Johannes Freitag, Anaïs Orsi, Patricia Martinerie, Ilka Weikusat, Michael Dyonisius, Xavier Faïn, Kevin Fourteau, and Thomas Blunier
The Cryosphere, 18, 4379–4397, https://doi.org/10.5194/tc-18-4379-2024, https://doi.org/10.5194/tc-18-4379-2024, 2024
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We study the EastGRIP area, Greenland, in detail with traditional and novel techniques. Due to the compaction of the ice, at a certain depth, atmospheric gases can no longer exchange, and the atmosphere is trapped in air bubbles in the ice. We find this depth by pumping air from a borehole, modeling, and using a new technique based on the optical appearance of the ice. Our results suggest that the close-off depth lies at around 58–61 m depth and more precisely at 58.3 m depth.
Fyntan Shaw, Andrew M. Dolman, Torben Kunz, Vasileios Gkinis, and Thomas Laepple
The Cryosphere, 18, 3685–3698, https://doi.org/10.5194/tc-18-3685-2024, https://doi.org/10.5194/tc-18-3685-2024, 2024
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Fast variability of water isotopes in ice cores is attenuated by diffusion but can be restored if the diffusion length is accurately estimated. Current estimation methods are inadequate for deep ice, mischaracterising millennial-scale climate variability. We address this using variability estimates from shallower ice. The estimated diffusion length of 31 cm for the bottom of the Dome C ice core is 20 cm less than the old method, enabling signal recovery on timescales previously considered lost.
Vasilii V. Petrenko, Segev BenZvi, Michael Dyonisius, Benjamin Hmiel, Andrew M. Smith, and Christo Buizert
The Cryosphere, 18, 3439–3451, https://doi.org/10.5194/tc-18-3439-2024, https://doi.org/10.5194/tc-18-3439-2024, 2024
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This manuscript presents the concept for a new proxy for past variations in the galactic cosmic ray flux (GCR). Past variations in GCR flux are important to understand for interpretation of records of isotopes produced by cosmic rays; these records are used for reconstructing solar variations and past land ice extent. The proxy involves using measurements of 14CO in ice cores, which should provide an uncomplicated and precise estimate of past GCR flux variations for the past few thousand years.
Benjamin Hmiel, Vasilii V. Petrenko, Christo Buizert, Andrew M. Smith, Michael N. Dyonisius, Philip Place, Bin Yang, Quan Hua, Ross Beaudette, Jeffrey P. Severinghaus, Christina Harth, Ray F. Weiss, Lindsey Davidge, Melisa Diaz, Matthew Pacicco, James A. Menking, Michael Kalk, Xavier Faïn, Alden Adolph, Isaac Vimont, and Lee T. Murray
The Cryosphere, 18, 3363–3382, https://doi.org/10.5194/tc-18-3363-2024, https://doi.org/10.5194/tc-18-3363-2024, 2024
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The main aim of this research is to improve understanding of carbon-14 that is produced by cosmic rays in ice sheets. Measurements of carbon-14 in ice cores can provide a range of useful information (age of ice, past atmospheric chemistry, past cosmic ray intensity). Our results show that almost all (>99 %) of carbon-14 that is produced in the upper layer of ice sheets is rapidly lost to the atmosphere. Our results also provide better estimates of carbon-14 production rates in deeper ice.
Xinyu Lv, Zhihao Cui, Ting Wang, Yumin Wen, An Liu, and Rusheng Wang
The Cryosphere, 18, 3351–3362, https://doi.org/10.5194/tc-18-3351-2024, https://doi.org/10.5194/tc-18-3351-2024, 2024
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In this study, the formation process of ice chips was observed and the fracture mechanics characteristics of the ice during the cutting process were analyzed. Additionally, a mechanical model for the cutting force was established based on the observation and analysis results. Finally, influencing factors and laws of the cutting force were verified by cutting force test results generated under various experimental conditions.
Jenna A. Epifanio, Edward J. Brook, Christo Buizert, Erin C. Pettit, Jon S. Edwards, John M. Fegyveresi, Todd A. Sowers, Jeffrey P. Severinghaus, and Emma C. Kahle
The Cryosphere, 17, 4837–4851, https://doi.org/10.5194/tc-17-4837-2023, https://doi.org/10.5194/tc-17-4837-2023, 2023
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The total air content (TAC) of polar ice cores has long been considered a potential proxy for past ice sheet elevation. This study presents a high-resolution record of TAC from the South Pole ice core. The record reveals orbital- and millennial-scale variability that cannot be explained by elevation changes. The orbital- and millennial-scale changes are likely a product of firn grain metamorphism near the surface of the ice sheet, due to summer insolation changes or local accumulation changes.
Marie G. P. Cavitte, Hugues Goosse, Kenichi Matsuoka, Sarah Wauthy, Vikram Goel, Rahul Dey, Bhanu Pratap, Brice Van Liefferinge, Thamban Meloth, and Jean-Louis Tison
The Cryosphere, 17, 4779–4795, https://doi.org/10.5194/tc-17-4779-2023, https://doi.org/10.5194/tc-17-4779-2023, 2023
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The net accumulation of snow over Antarctica is key for assessing current and future sea-level rise. Ice cores record a noisy snowfall signal to verify model simulations. We find that ice core net snowfall is biased to lower values for ice rises and the Dome Fuji site (Antarctica), while the relative uncertainty in measuring snowfall increases rapidly with distance away from the ice core sites at the ice rises but not at Dome Fuji. Spatial variation in snowfall must therefore be considered.
Anja Løkkegaard, Kenneth D. Mankoff, Christian Zdanowicz, Gary D. Clow, Martin P. Lüthi, Samuel H. Doyle, Henrik H. Thomsen, David Fisher, Joel Harper, Andy Aschwanden, Bo M. Vinther, Dorthe Dahl-Jensen, Harry Zekollari, Toby Meierbachtol, Ian McDowell, Neil Humphrey, Anne Solgaard, Nanna B. Karlsson, Shfaqat A. Khan, Benjamin Hills, Robert Law, Bryn Hubbard, Poul Christoffersen, Mylène Jacquemart, Julien Seguinot, Robert S. Fausto, and William T. Colgan
The Cryosphere, 17, 3829–3845, https://doi.org/10.5194/tc-17-3829-2023, https://doi.org/10.5194/tc-17-3829-2023, 2023
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This study presents a database compiling 95 ice temperature profiles from the Greenland ice sheet and peripheral ice caps. Ice viscosity and hence ice flow are highly sensitive to ice temperature. To highlight the value of the database in evaluating ice flow simulations, profiles from the Greenland ice sheet are compared to a modeled temperature field. Reoccurring discrepancies between modeled and observed temperatures provide insight on the difficulties faced when simulating ice temperatures.
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.
Takashi Obase, Ayako Abe-Ouchi, Fuyuki Saito, Shun Tsutaki, Shuji Fujita, Kenji Kawamura, and Hideaki Motoyama
The Cryosphere, 17, 2543–2562, https://doi.org/10.5194/tc-17-2543-2023, https://doi.org/10.5194/tc-17-2543-2023, 2023
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We use a one-dimensional ice-flow model to examine the most suitable core location near Dome Fuji (DF), Antarctica. This model computes the temporal evolution of age and temperature from past to present. We investigate the influence of different parameters of climate and ice sheet on the ice's basal age and compare the results with ground radar surveys. We find that the local ice thickness primarily controls the age because it is critical to the basal melting, which can eliminate the old ice.
Nicolas Stoll, Julien Westhoff, Pascal Bohleber, Anders Svensson, Dorthe Dahl-Jensen, Carlo Barbante, and Ilka Weikusat
The Cryosphere, 17, 2021–2043, https://doi.org/10.5194/tc-17-2021-2023, https://doi.org/10.5194/tc-17-2021-2023, 2023
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Impurities in polar ice play a role regarding its climate signal and internal deformation. We bridge different scales using different methods to investigate ice from the Last Glacial Period derived from the EGRIP ice core in Greenland. We characterise different types of cloudy bands, i.e. frequently occurring milky layers in the ice, and analyse their chemistry with Raman spectroscopy and 2D imaging. We derive new insights into impurity localisation and deposition conditions.
Niccolò Maffezzoli, Eliza Cook, Willem G. M. van der Bilt, Eivind N. Støren, Daniela Festi, Florian Muthreich, Alistair W. R. Seddon, François Burgay, Giovanni Baccolo, Amalie R. F. Mygind, Troels Petersen, Andrea Spolaor, Sebastiano Vascon, Marcello Pelillo, Patrizia Ferretti, Rafael S. dos Reis, Jefferson C. Simões, Yuval Ronen, Barbara Delmonte, Marco Viccaro, Jørgen Peder Steffensen, Dorthe Dahl-Jensen, Kerim H. Nisancioglu, and Carlo Barbante
The Cryosphere, 17, 539–565, https://doi.org/10.5194/tc-17-539-2023, https://doi.org/10.5194/tc-17-539-2023, 2023
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Multiple lines of research in ice core science are limited by manually intensive and time-consuming optical microscopy investigations for the detection of insoluble particles, from pollen grains to volcanic shards. To help overcome these limitations and support researchers, we present a novel methodology for the identification and autonomous classification of ice core insoluble particles based on flow image microscopy and neural networks.
Tomotaka Saruya, Shuji Fujita, Yoshinori Iizuka, Atsushi Miyamoto, Hiroshi Ohno, Akira Hori, Wataru Shigeyama, Motohiro Hirabayashi, and Kumiko Goto-Azuma
The Cryosphere, 16, 2985–3003, https://doi.org/10.5194/tc-16-2985-2022, https://doi.org/10.5194/tc-16-2985-2022, 2022
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Crystal orientation fabrics (COF) of the Dome Fuji ice core were investigated with an innovative method with unprecedentedly high statistical significance and dense depth coverage. The COF profile and its fluctuation were found to be highly dependent on concentrations of chloride ion and dust. The data suggest deformation of ice at the deepest zone is highly influenced by COF fluctuations that progressively develop from the near-surface firn toward the deepest zone within ice sheets.
Jacob D. Morgan, Christo Buizert, Tyler J. Fudge, Kenji Kawamura, Jeffrey P. Severinghaus, and Cathy M. Trudinger
The Cryosphere, 16, 2947–2966, https://doi.org/10.5194/tc-16-2947-2022, https://doi.org/10.5194/tc-16-2947-2022, 2022
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The composition of air bubbles in Antarctic ice cores records information about past changes in properties of the snowpack. We find that, near the South Pole, thinner snowpack in the past is often due to steeper surface topography, in which faster winds erode the snow and deposit it in flatter areas. The slope and wind seem to also cause a seasonal bias in the composition of air bubbles in the ice core. These findings will improve interpretation of other ice cores from places with steep slopes.
Nicolas Stoll, Maria Hörhold, Tobias Erhardt, Jan Eichler, Camilla Jensen, and Ilka Weikusat
The Cryosphere, 16, 667–688, https://doi.org/10.5194/tc-16-667-2022, https://doi.org/10.5194/tc-16-667-2022, 2022
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We mapped and analysed solid inclusion in the upper 1340 m of the EGRIP ice core with Raman spectroscopy and microstructure mapping, based on bulk dust content derived via continuous flow analysis. We observe a large variety in mineralogy throughout the core and samples. The main minerals are sulfates, especially gypsum, and terrestrial dust minerals, such as quartz, mica, and feldspar. A change in mineralogy occurs around 900 m depth indicating a climate-related imprint.
Nicolas Stoll, Jan Eichler, Maria Hörhold, Tobias Erhardt, Camilla Jensen, and Ilka Weikusat
The Cryosphere, 15, 5717–5737, https://doi.org/10.5194/tc-15-5717-2021, https://doi.org/10.5194/tc-15-5717-2021, 2021
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We did a systematic analysis of the location of inclusions in the EGRIP ice core, the first ice core from an ice stream. We combine this with crystal orientation and grain size data, enabling the first overview about the microstructure of this unique ice core. Micro-inclusions show a strong spatial variability and patterns (clusters or horizontal layers); roughly one-third is located at grain boundaries. More holistic approaches are needed to understand deformation processes in the ice better.
Ikumi Oyabu, Kenji Kawamura, Tsutomu Uchida, Shuji Fujita, Kyotaro Kitamura, Motohiro Hirabayashi, Shuji Aoki, Shinji Morimoto, Takakiyo Nakazawa, Jeffrey P. Severinghaus, and Jacob D. Morgan
The Cryosphere, 15, 5529–5555, https://doi.org/10.5194/tc-15-5529-2021, https://doi.org/10.5194/tc-15-5529-2021, 2021
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We present O2/N2 and Ar/N2 records from the Dome Fuji ice core through the bubbly ice, bubble–clathrate transition, and clathrate ice zones without gas-loss fractionation. The insolation signal is preserved through the clathrate formation. The relationship between Ar/Ν2 and Ο2/Ν2 suggests that the fractionation for the bubble–clathrate transition is mass independent, while the bubble close-off process involves a combination of mass-independent and mass-dependent fractionation for O2 and Ar.
Pascal Bohleber, Marco Roman, Martin Šala, Barbara Delmonte, Barbara Stenni, and Carlo Barbante
The Cryosphere, 15, 3523–3538, https://doi.org/10.5194/tc-15-3523-2021, https://doi.org/10.5194/tc-15-3523-2021, 2021
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Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) offers micro-destructive, micrometer-scale impurity analysis of ice cores. For improved understanding of the LA-ICP-MS signals, novel 2D impurity imaging is applied to selected glacial and interglacial samples of Antarctic deep ice cores. This allows evaluating the 2D impurity distribution in relation to ice crystal features and assessing implications for investigating highly thinned climate proxy signals in deep polar ice.
David A. Lilien, Daniel Steinhage, Drew Taylor, Frédéric Parrenin, Catherine Ritz, Robert Mulvaney, Carlos Martín, Jie-Bang Yan, Charles O'Neill, Massimo Frezzotti, Heinrich Miller, Prasad Gogineni, Dorthe Dahl-Jensen, and Olaf Eisen
The Cryosphere, 15, 1881–1888, https://doi.org/10.5194/tc-15-1881-2021, https://doi.org/10.5194/tc-15-1881-2021, 2021
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We collected radar data between EDC, an ice core spanning ~800 000 years, and BELDC, the site chosen for a new
oldest icecore at nearby Little Dome C. These data allow us to identify 50 % older internal horizons than previously traced in the area. We fit a model to the ages of those horizons at BELDC to determine the age of deep ice there. We find that there is likely to be 1.5 Myr old ice ~265 m above the bed, with sufficient resolution to preserve desired climatic information.
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.
Kévin Fourteau, Patricia Martinerie, Xavier Faïn, Christoph F. Schaller, Rebecca J. Tuckwell, Henning Löwe, Laurent Arnaud, Olivier Magand, Elizabeth R. Thomas, Johannes Freitag, Robert Mulvaney, Martin Schneebeli, and Vladimir Ya. Lipenkov
The Cryosphere, 13, 3383–3403, https://doi.org/10.5194/tc-13-3383-2019, https://doi.org/10.5194/tc-13-3383-2019, 2019
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Understanding gas trapping in polar ice is essential to study the relationship between greenhouse gases and past climates. New data of bubble closure, used in a simple gas-trapping model, show inconsistency with the final air content in ice. This suggests gas trapping is not fully understood. We also use a combination of high-resolution measurements to investigate the effect of polar snow stratification on gas trapping and find that all strata have similar pores, but that some close in advance.
Youngjoon Jang, Sang Bum Hong, Christo Buizert, Hun-Gyu Lee, Sang-Young Han, Ji-Woong Yang, Yoshinori Iizuka, Akira Hori, Yeongcheol Han, Seong Joon Jun, Pieter Tans, Taejin Choi, Seong-Joong Kim, Soon Do Hur, and Jinho Ahn
The Cryosphere, 13, 2407–2419, https://doi.org/10.5194/tc-13-2407-2019, https://doi.org/10.5194/tc-13-2407-2019, 2019
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We can learn how human activity altered atmospheric air from the interstitial air in the porous snow layer (firn) on top of glaciers. However, old firn air (> 55 years) was observed only at sites where surface temperatures and snow accumulation rates are very low, such as the South Pole. In this study, we report an unusually old firn air with CO2 age of 93 years from Styx Glacier, near the Ross Sea coast in Antarctica. We hypothesize that the large snow density variations increase firn air ages.
Nanna B. Karlsson, Tobias Binder, Graeme Eagles, Veit Helm, Frank Pattyn, Brice Van Liefferinge, and Olaf Eisen
The Cryosphere, 12, 2413–2424, https://doi.org/10.5194/tc-12-2413-2018, https://doi.org/10.5194/tc-12-2413-2018, 2018
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In this study, we investigate the probability that the Dome Fuji region in East Antarctica contains ice more than 1.5 Ma old. The retrieval of a continuous ice-core record extending beyond 1 Ma is imperative to understand why the frequency of ice ages changed from 40 to 100 ka approximately 1 Ma ago.
We use a new radar dataset to improve the ice thickness maps, and apply a thermokinematic model to predict basal temperature and age of the ice. Our results indicate several areas of interest.
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Short summary
In 1966, the U.S. Army drilled through the Greenland Ice Sheet at Camp Century, Greenland; they recovered 3.44 m of frozen material. Here, we decipher the material’s history. Water, flowing during a warm interglacial when the ice sheet melted from northwest Greenland, deposited the upper material which contains fossil plant and insect parts. The lower material, separated by more than a meter of ice with some sediment, is till, deposited by the ice sheet during a prior cold period.
In 1966, the U.S. Army drilled through the Greenland Ice Sheet at Camp Century, Greenland; they...
