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1. Reconstruction of ice-sheet changes in the Antarctic Peninsula since the Last Glacial Maximum

Author

Ó Cofaigh, Colm, Davies, Bethan J., Livingstone, Stephen J., Smith, James A., Johnson, Joanne S., Hocking, Emma P., Hodgson, Dominic A., Anderson, John B., Bentley, Michael J., Canals, Miquel, Domack, Eugene, Dowdeswell, Julian A., Evans, Jeffrey, Glasser, Neil F., Hillenbrand, Claus-Dieter, Larter, Robert D., Roberts, Stephen J., and Simms, Alexander R.

Subjects
Deglaciation, Global and Planetary Change, Last Glacial Maximum, Antarctic Peninsula Ice Sheet, Antarctica, F800, Geology, F600, Glacial geology, Ecology, Evolution, Behavior and Systematics
Abstract

This paper compiles and reviews marine and terrestrial data constraining the dimensions and configuration of the Antarctic Peninsula Ice Sheet (APIS) from the Last Glacial Maximum (LGM) through deglaciation to the present day. These data are used to reconstruct grounding-line retreat in 5 ka time-steps from 25 ka BP to present. Glacial landforms and subglacial tills on the eastern and western Antarctic Peninsula (AP) shelf indicate that the APIS was grounded to the outer shelf/shelf edge at the LGM and contained a series of fast-flowing ice streams that drained along cross-shelf bathymetric troughs. The ice sheet was grounded at the shelf edge until ∼20 cal ka BP. Chronological control on retreat is provided by radiocarbon dates on glacimarine sediments from the shelf troughs and on lacustrine and terrestrial organic remains, as well as cosmogenic nuclide dates on erratics and ice moulded bedrock. Retreat in the east was underway by about 18 cal ka BP. The earliest dates on recession in the west are from Bransfield Basin where recession was underway by 17.5 cal ka BP. Ice streams were active during deglaciation at least until the ice sheet had pulled back to the mid-shelf. The timing of initial retreat decreased progressively southwards along the western AP shelf; the large ice stream in Marguerite Trough may have remained grounded at the shelf edge until about 14 cal ka BP, although terrestrial cosmogenic nuclide ages indicate that thinning had commenced by 18 ka BP. Between 15 and 10 cal ka BP the APIS underwent significant recession along the western AP margin, although retreat between individual troughs was asynchronous. Ice in Marguerite Trough may have still been grounded on the mid-shelf at 10 cal ka BP. In the Larsen-A region the transition from grounded to floating ice was established by 10.7–10.6 cal ka BP. The APIS had retreated towards its present configuration in the western AP by the mid-Holocene but on the eastern peninsula may have approached its present configuration several thousand years earlier, by the start of the Holocene. Mid to late-Holocene retreat was diachronous with stillstands, re-advances and changes in ice-shelf configuration being recorded in most places. Subglacial topography exerted a major control on grounding-line retreat with grounding-zone wedges, and thus by inference slow-downs or stillstands in the retreat of the grounding line, occurring in some cases on reverse bed slopes.

Published
2014
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2. A community-based geological reconstruction of Antarctic Ice Sheet deglaciation since the Last Glacial Maximum

Author

Bentley, Michael J., Ó Cofaigh, Colm, Anderson, John B., Conway, Howard, Davies, Bethan, Graham, Alastair G.C., Hillenbrand, Claus-Dieter, Hodgson, Dominic A., Jamieson, Stewart S.R., Larter, Robert, Mackintosh, Andrew N., Smith, James A., Verleyen, Elie, Ackert, Robert, Bart, Philip J., Berg, Sonja, Brunstein, Daniel, Canals, Miquel, Colhoun, Eric A., Crosta, Xavier, Dickens, William A., Domack, Eugene, Dowdeswell, Julia, Dunbar, Robert, Ehrmann, Werner, Evans, Jeffrey, Favier, Vincent, Fink, David, Fogwill, Christopher J., Glasser, Neil F., Gohl, Karsten, Golledge, Nicholas R., Goodwin, Ian, Gore, Damian B., Greenwood, Sarah L., Hall, Brenda L., Hall, Kevin, Hedding, David W., Hein, Andrew S., Hocking, Emma P., Jakobsson, Martin, Johnson, Joanne S., Jomelli, Vincent, Jones, R. Selwyn, Klages, Johann P., Kristoffersen, Yngve, Kuhn, Gerhard, Leventer, Amy, Licht, Kathy, Lilly, Katherine, Lindow, Julia, Livingstone, Stephen J., Massé, Guillaume, Mcglone, Matt S., Mckay, Robert, Melles, Martin, Miura, Hideki, Mulvaney, Robert, Nel, Werner, Nitsche, Frank O., O'Brien, Philip E., Post, Alexandra L., Roberts, Stephen J., Saunders, Krystyna M., Selkirk, Patricia M., Simms, Alexander R., Spiegel, Cornelia, Stolldorf, Travis D., Sugden, David E., van Der Putten, Nathalie, van Ommen, Tas, Verfaillie, Deborah, Vyverman, Wim, Wagner, Bernd, White, Duanne A., Witus, Alexandra E., Zwartz, Dan, Department of Geography, Durham University, School of Oceanography [Seattle], University of Washington [Seattle], Biological and Biomedical Sciences, Glasgow Caledonian University (GCU), British Antarctic Survey (BAS), Natural Environment Research Council (NERC), Universiteit Gent = Ghent University (UGENT), Laboratoire de géographie physique : Environnements Quaternaires et Actuels (LGP), Université Paris 1 Panthéon-Sorbonne (UP1)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), GRC Geociencies Marines, GRC, School of Environmental and Life Sciences, The University of Newcastle, Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Space Research Institute of Austrian Academy of Sciences (IWF), Austrian Academy of Sciences (OeAW), College of Marine Science [St Petersburg, FL], University of South Florida [Tampa] (USF), Scott Polar Research Institute, University of Cambridge [UK] (CAM), Stanford University, Centre for glaciology, Department of Geography and Earth Sciences (DGES), Aberystwyth University-Aberystwyth University, Department of biomedical sciences, University of Prince Edward Island, University of Calgary, Department of Evolutionary Biology, Uppsala University, Institute for Biomechanics, Colgate University, Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Takuvik Joint International Laboratory ULAVAL-CNRS, Université Laval [Québec] (ULaval)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institute of integrative biology (Liverpool), University of Liverpool, Paul Scherrer Institute (PSI), NIFS, National Institute for Fusion Science (NIFS), Gent University, Department of Biology, Lamont-Doherty Earth Observatory (LDEO), Columbia University [New York], University of West London, Dpt Biological Sciences, Macquarie University, Macquarie University, Division of Migratory Birds - Northeast Region, US Fish and Wildlife Service, Lund University [Lund], UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Department of Geology and Geochemistry [Stockholm], Stockholm University, Centre National de la Recherche Scientifique (CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Université Panthéon-Sorbonne (UP1), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS), Protistology and Aquatic Ecology, Ghent University, Universiteit Gent = Ghent University [Belgium] (UGENT), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Laval [Québec] (ULaval)-Centre National de la Recherche Scientifique (CNRS), and Earth and Climate

Subjects
Matematikk og naturvitenskap: 400::Geofag: 450::Kvartærgeologi, glasiologi: 465 [VDP], [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Modelling, Mathematics and natural scienses: 400::Geosciences: 450::Quaternary geology, glaciology: 465 [VDP], Quaternary, HISTORY, MASS-BALANCE, COLLAPSE, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, Ecology, Evolution, Behavior and Systematics, ComputingMilieux_MISCELLANEOUS, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Global and Planetary Change, WEDDELL SEA EMBAYMENT, CONSTRAINTS, LEVEL CHANGE, Geology, RETREAT, Antarctic Ice Sheet, STREAM STABILITY, Glacial geology, ISOSTATIC-ADJUSTMENT, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, Earth and Environmental Sciences, PENINSULA
Abstract

The Weddell Sea sector is one of the main formation sites for Antarctic Bottom Water and an outlet for about one fifth of Antarctica’s continental ice volume. Over the last few decades, studies on glacialegeological records in this sector have provided conflicting reconstructions of changes in ice-sheet extent and ice-sheet thickness since the Last Glacial Maximum (LGM at ca 23e19 calibrated kiloyears before present, cal ka BP). Terrestrial geomorphological records and exposure ages obtained from rocks in the hinterland of the Weddell Sea, ice-sheet thickness constraints from ice cores and some radiocarbon dates on offshore sediments were interpreted to indicate no significant ice thickening and locally restricted grounding-line advance at the LGM. Other marine geological and geophysical studies concluded that subglacial bedforms mapped on theWeddell Sea continental shelf, subglacial deposits and sediments over-compacted by overriding ice recovered in cores, and the few available radiocarbon ages from marine sediments are consistent with major ice-sheet advance at the LGM. Reflecting the geological interpretations, different icesheet models have reconstructed conflicting LGM ice-sheet configurations for the Weddell Sea sector. Consequently, the estimated contributions of ice-sheet build-up in the Weddell Sea sector to the LGM sealevel low-stand of w130 m vary considerably. In this paper, we summarise and review the geological records of past ice-sheet margins and past icesheet elevations in the Weddell Sea sector. We compile marine and terrestrial chronological data constraining former ice-sheet size, thereby highlighting different levels of certainty, and present two alternative scenarios of the LGM ice-sheet configuration, including time-slice reconstructions for post- LGM grounding-line retreat. Moreover, we discuss consistencies and possible reasons for inconsistencies between the various reconstructions and propose objectives for future research. The aim of our study is to provide two alternative interpretations of glacialegeological datasets on Antarctic Ice- Sheet History for the Weddell Sea sector, which can be utilised to test and improve numerical icesheet models

Published
2014
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3. Glacial geomorphology of Marguerite Bay Palaeo-Ice stream, western Antarctic Peninsula

Author

Livingstone, Stephen J., Ó Cofaigh, Colm, Stokes, Chris R., Hillenbrand, Claus-Dieter, Vieli, Andreas, Jamieson, Stewart S.R., and University of Zurich

Subjects
Palaeo-ice stream, 10122 Institute of Geography, 3305 Geography, Planning and Development, Marine, 1901 Earth and Planetary Sciences (miscellaneous), Antarctica, Geology, Bedform variability, 910 Geography & travel, Glacial geomorphology
Abstract

This paper presents a glacial geomorphological map of over 17,000 landforms on the bed of a major palaeo-ice stream in Marguerite Bay, western Antarctic Peninsula. The map was compiled using various geophysical datasets from multiple marine research cruises. Eight glacial landform types are identified: mega-scale glacial lineations, crag-and-tails, whalebacks, gouged, grooved and streamlined bedrock, grounding-zone wedges, subglacial meltwater channels, gullies and channels, and iceberg scours. The map represents one of the most complete marine ice-stream signatures available for scrutiny, and these data hold much potential for reconstructing former ice sheet dynamics, testing numerical ice sheet models, and understanding the formation of subglacial bedforms beneath ice streams. In particular, they record a complex bedform signature of palaeo-ice stream flow and retreat since the last glacial maximum, characterised by considerable spatial variability and strongly influenced by the underlying geology. The map is presented at a scale of 1: 750,000, designed to be printed at A2 size, and encompasses an area of 128,420 km2.

Published
2013

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