Articles | Volume 14, issue 9
https://doi.org/10.5194/tc-14-2883-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/tc-14-2883-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
09 Sep 2020
Research article |
| 09 Sep 2020
| 09 Sep 2020
Revealing the former bed of Thwaites Glacier using sea-floor bathymetry: implications for warm-water routing and bed controls on ice flow and buttressing
British Antarctic Survey, Natural Environment Research Council,
High Cross, Madingley Road, Cambridge, CB3 0ET, UK
Robert D. Larter
British Antarctic Survey, Natural Environment Research Council,
High Cross, Madingley Road, Cambridge, CB3 0ET, UK
Alastair G. C. Graham
College of
Marine Science, University of South Florida, Saint Petersburg, FL 33701, USA
Robert Arthern
British Antarctic Survey, Natural Environment Research Council,
High Cross, Madingley Road, Cambridge, CB3 0ET, UK
James D. Kirkham
British Antarctic Survey, Natural Environment Research Council,
High Cross, Madingley Road, Cambridge, CB3 0ET, UK
Scott Polar Research Institute, University of Cambridge, Lensfield
Road, Cambridge, CB2 1ER, UK
Rebecca L. Totten
Department of Geological Sciences, University of Alabama, Tuscaloosa,
AL 35487, USA
Tom A. Jordan
British Antarctic Survey, Natural Environment Research Council,
High Cross, Madingley Road, Cambridge, CB3 0ET, UK
Rachel Clark
Department of Earth and Atmospheric Sciences, University of Houston,
Houston, TX 77204, USA
Victoria Fitzgerald
Department of Geological Sciences, University of Alabama, Tuscaloosa,
AL 35487, USA
Anna K. Wåhlin
Department of Marine Sciences, University of Gothenburg, 40530
Göteborg, Sweden
John B. Anderson
Department of Earth Science, Rice University, Houston, TX 77005, USA
Claus-Dieter Hillenbrand
British Antarctic Survey, Natural Environment Research Council,
High Cross, Madingley Road, Cambridge, CB3 0ET, UK
Frank O. Nitsche
Lamont-Doherty Earth Observatory, Columbia University, Palisades, New
York, NY, USA
Lauren Simkins
Department of Environmental Sciences, University of Virginia,
Charlottesville, VA 22904, USA
James A. Smith
British Antarctic Survey, Natural Environment Research Council,
High Cross, Madingley Road, Cambridge, CB3 0ET, UK
Karsten Gohl
Alfred Wegener Institute Helmholtz-Centre for Polar and Marine
Research, 27568 Bremerhaven, Germany
Jan Erik Arndt
Alfred Wegener Institute Helmholtz-Centre for Polar and Marine
Research, 27568 Bremerhaven, Germany
Jongkuk Hong
Korea Polar Research Institute (KOPRI), Incheon 21990, Republic of
Korea
Julia Wellner
Department of Earth and Atmospheric Sciences, University of Houston,
Houston, TX 77204, USA
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Michael J. Bentley, James A. Smith, Stewart S. R. Jamieson, Margaret R. Lindeman, Brice R. Rea, Angelika Humbert, Timothy P. Lane, Christopher M. Darvill, Jeremy M. Lloyd, Fiamma Straneo, Veit Helm, and David H. Roberts
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James W. Marschalek, Edward Gasson, Tina van de Flierdt, Claus-Dieter Hillenbrand, Martin J. Siegert, and Liam Holder
Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmd-2023-8, https://doi.org/10.5194/gmd-2023-8, 2023
Revised manuscript not accepted
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Ice sheet models can help predict how Antarctica’s ice sheets respond to environmental change; such models benefit from comparison to geological data. Here, we use ice sheet model results, plus other data, to predict the erosion of Antarctic debris and trace its transport to where it is deposited on the ocean floor. This allows the results of ice sheet modelling to be directly and quantitively compared to real-world data, helping to reduce uncertainty regarding Antarctic sea level contribution.
James A. Smith, Louise Callard, Michael J. Bentley, Stewart S. R. Jamieson, Maria Luisa Sánchez-Montes, Timothy P. Lane, Jeremy M. Lloyd, Erin L. McClymont, Christopher M. Darvill, Brice R. Rea, Colm O'Cofaigh, Pauline Gulliver, Werner Ehrmann, Richard S. Jones, and David H. Roberts
The Cryosphere, 17, 1247–1270, https://doi.org/10.5194/tc-17-1247-2023, https://doi.org/10.5194/tc-17-1247-2023, 2023
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The Greenland Ice Sheet is melting at an accelerating rate. To understand the significance of these changes we reconstruct the history of one of its fringing ice shelves, known as 79° N ice shelf. We show that the ice shelf disappeared 8500 years ago, following a period of enhanced warming. An important implication of our study is that 79° N ice shelf is susceptible to collapse when atmospheric and ocean temperatures are ~2°C warmer than present, which could occur by the middle of this century.
Paul R. Holland, Gemma K. O'Connor, Thomas J. Bracegirdle, Pierre Dutrieux, Kaitlin A. Naughten, Eric J. Steig, David P. Schneider, Adrian Jenkins, and James A. Smith
The Cryosphere, 16, 5085–5105, https://doi.org/10.5194/tc-16-5085-2022, https://doi.org/10.5194/tc-16-5085-2022, 2022
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The Antarctic Ice Sheet is losing ice, causing sea-level rise. However, it is not known whether human-induced climate change has contributed to this ice loss. In this study, we use evidence from climate models and palaeoclimate measurements (e.g. ice cores) to suggest that the ice loss was triggered by natural climate variations but is now sustained by human-forced climate change. This implies that future greenhouse-gas emissions may influence sea-level rise from Antarctica.
Dominic A. Hodgson, Tom A. Jordan, Neil Ross, Teal R. Riley, and Peter T. Fretwell
The Cryosphere, 16, 4797–4809, https://doi.org/10.5194/tc-16-4797-2022, https://doi.org/10.5194/tc-16-4797-2022, 2022
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This paper describes the drainage (and refill) of a subglacial lake on the Antarctic Peninsula resulting in the collapse of the overlying ice into the newly formed subglacial cavity. It provides evidence of an active hydrological network under the region's glaciers and close coupling between surface climate processes and the base of the ice.
Alice C. Frémand, Julien A. Bodart, Tom A. Jordan, Fausto Ferraccioli, Carl Robinson, Hugh F. J. Corr, Helen J. Peat, Robert G. Bingham, and David G. Vaughan
Earth Syst. Sci. Data, 14, 3379–3410, https://doi.org/10.5194/essd-14-3379-2022, https://doi.org/10.5194/essd-14-3379-2022, 2022
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This paper presents the release of large swaths of airborne geophysical data (including gravity, magnetics, and radar) acquired between 1994 and 2020 over Antarctica by the British Antarctic Survey. These include a total of 64 datasets from 24 different surveys, amounting to >30 % of coverage over the Antarctic Ice Sheet. This paper discusses how these data were acquired and processed and presents the methods used to standardize and publish the data in an interactive and reproducible manner.
Astrid Oetting, Emma C. Smith, Jan Erik Arndt, Boris Dorschel, Reinhard Drews, Todd A. Ehlers, Christoph Gaedicke, Coen Hofstede, Johann P. Klages, Gerhard Kuhn, Astrid Lambrecht, Andreas Läufer, Christoph Mayer, Ralf Tiedemann, Frank Wilhelms, and Olaf Eisen
The Cryosphere, 16, 2051–2066, https://doi.org/10.5194/tc-16-2051-2022, https://doi.org/10.5194/tc-16-2051-2022, 2022
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This study combines a variety of geophysical measurements in front of and beneath the Ekström Ice Shelf in order to identify and interpret geomorphological evidences of past ice sheet flow, extent and retreat.
The maximal extent of grounded ice in this region was 11 km away from the continental shelf break.
The thickness of palaeo-ice on the calving front around the LGM was estimated to be at least 305 to 320 m.
We provide essential boundary conditions for palaeo-ice-sheet models.
Matthew Chadwick, Claire S. Allen, Louise C. Sime, Xavier Crosta, and Claus-Dieter Hillenbrand
Clim. Past, 18, 129–146, https://doi.org/10.5194/cp-18-129-2022, https://doi.org/10.5194/cp-18-129-2022, 2022
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Algae preserved in marine sediments have allowed us to reconstruct how much winter sea ice was present around Antarctica during a past time period (130 000 years ago) when the climate was warmer than today. The patterns of sea-ice increase and decrease vary between different parts of the Southern Ocean. The Pacific sector has a largely stable sea-ice extent, whereas the amount of sea ice in the Atlantic sector is much more variable with bigger decreases and increases than other regions.
Nele Lamping, Juliane Müller, Jens Hefter, Gesine Mollenhauer, Christian Haas, Xiaoxu Shi, Maria-Elena Vorrath, Gerrit Lohmann, and Claus-Dieter Hillenbrand
Clim. Past, 17, 2305–2326, https://doi.org/10.5194/cp-17-2305-2021, https://doi.org/10.5194/cp-17-2305-2021, 2021
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We analysed biomarker concentrations on surface sediment samples from the Antarctic continental margin. Highly branched isoprenoids and GDGTs are used for reconstructing recent sea-ice distribution patterns and ocean temperatures respectively. We compared our biomarker-based results with data obtained from satellite observations and estimated from a numerical model and find reasonable agreements. Further, we address caveats and provide recommendations for future investigations.
Charlotte L. Spencer-Jones, Erin L. McClymont, Nicole J. Bale, Ellen C. Hopmans, Stefan Schouten, Juliane Müller, E. Povl Abrahamsen, Claire Allen, Torsten Bickert, Claus-Dieter Hillenbrand, Elaine Mawbey, Victoria Peck, Aleksandra Svalova, and James A. Smith
Biogeosciences, 18, 3485–3504, https://doi.org/10.5194/bg-18-3485-2021, https://doi.org/10.5194/bg-18-3485-2021, 2021
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Long-term ocean temperature records are needed to fully understand the impact of West Antarctic Ice Sheet collapse. Glycerol dialkyl glycerol tetraethers (GDGTs) are powerful tools for reconstructing ocean temperature but can be difficult to apply to the Southern Ocean. Our results show active GDGT synthesis in relatively warm depths of the ocean. This research improves the application of GDGT palaeoceanographic proxies in the Southern Ocean.
Romana Melis, Lucilla Capotondi, Fiorenza Torricella, Patrizia Ferretti, Andrea Geniram, Jong Kuk Hong, Gerhard Kuhn, Boo-Keun Khim, Sookwan Kim, Elisa Malinverno, Kyu Cheul Yoo, and Ester Colizza
J. Micropalaeontol., 40, 15–35, https://doi.org/10.5194/jm-40-15-2021, https://doi.org/10.5194/jm-40-15-2021, 2021
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Integrated micropaleontological (planktic and benthic foraminifera, diatoms, and silicoflagellates) analysis, together with textural and geochemical results of a deep-sea core from the Hallett Ridge (northwestern Ross Sea), provides new data for late Quaternary (23–2 ka) paleoenvironmental and paleoceanographic reconstructions of this region. Results allow us to identify three time intervals: the glacial–deglacial transition, the deglacial period, and the interglacial period.
Chris S. M. Turney, Richard T. Jones, Nicholas P. McKay, Erik van Sebille, Zoë A. Thomas, Claus-Dieter Hillenbrand, and Christopher J. Fogwill
Earth Syst. Sci. Data, 12, 3341–3356, https://doi.org/10.5194/essd-12-3341-2020, https://doi.org/10.5194/essd-12-3341-2020, 2020
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The Last Interglacial (129–116 ka) experienced global temperatures and sea levels higher than today. The direct contribution of warmer conditions to global sea level (thermosteric) are uncertain. We report a global network of sea surface temperatures. We find mean global annual temperature anomalies of 0.2 ± 0.1˚C and an early maximum peak of 0.9 ± 0.1˚C. Our reconstruction suggests warmer waters contributed on average 0.08 ± 0.1 m and a peak contribution of 0.39 ± 0.1 m to global sea level.
David R. Cox, Paul C. Knutz, D. Calvin Campbell, John R. Hopper, Andrew M. W. Newton, Mads Huuse, and Karsten Gohl
Sci. Dril., 28, 1–27, https://doi.org/10.5194/sd-28-1-2020, https://doi.org/10.5194/sd-28-1-2020, 2020
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A workflow is presented that uses 3D subsurface image (seismic) data to identify and avoid potential geological hazards, in order to increase safety and minimize the risk associated with selecting offshore scientific drilling locations. The workflow has been implemented for a scientific drilling expedition proposal within a challenging region offshore north-western Greenland and resulted in an improved understanding of subsurface hazards and a reduction of risk across all selected drill sites.
Tom A. Jordan, David Porter, Kirsty Tinto, Romain Millan, Atsuhiro Muto, Kelly Hogan, Robert D. Larter, Alastair G. C. Graham, and John D. Paden
The Cryosphere, 14, 2869–2882, https://doi.org/10.5194/tc-14-2869-2020, https://doi.org/10.5194/tc-14-2869-2020, 2020
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Linking ocean and ice sheet processes allows prediction of sea level change. Ice shelves form a floating buffer between the ice–ocean systems, but the water depth beneath is often a mystery, leaving a critical blind spot in our understanding of how these systems interact. Here, we use airborne measurements of gravity to reveal the bathymetry under the ice shelves flanking the rapidly changing Thwaites Glacier and adjacent glacier systems, providing new insights and data for future models.
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Short summary
The sea-floor geometry around the rapidly changing Thwaites Glacier is a key control on warm ocean waters reaching the ice shelf and grounding zone beyond. This area was previously unsurveyed due to icebergs and sea-ice cover. The International Thwaites Glacier Collaboration mapped this area for the first time in 2019. The data reveal troughs over 1200 m deep and, as this region is thought to have only ungrounded recently, provide key insights into the morphology beneath the grounded ice sheet.
The sea-floor geometry around the rapidly changing Thwaites Glacier is a key control on warm...
