Durham Research Online Deposited in DRO: 23 June 2014 Version of attached le: Accepted Version Peer-review status of attached le: Peer-reviewed Citation for published item: Hodgson, D.A. and Graham, A.G.C. and Roberts, S.J. and Bentley, M.J. and O¡ Cofaigh, C. and Verleyen, E. and Vyverman, W. and Jomelli, V. and Favier, V. and Brunstein, D. and Verfaillie, D. and Colhoun, E.A. and Saunders, K.M. and Selkirk, P.M. and Mackintosh, A. and Hedding, D.W. and Nel, W. and Hall, K. and McGlone, M.S. and Van der Putten, N. and Dickens, W.A. and Smith, J.A. (2014) 'Terrestrial and submarine evidence for the extent and timing of the Last Glacial Maximum and the onset of deglaciation on the maritime-Antarctic and sub-Antarctic islands.', Quaternary science reviews., 100 . pp. 137-158. Further information on publisher's website: http://dx.doi.org/10.1016/j.quascirev.2013.12.001 Publisher's copyright statement: c 2014 The Authors. Published by Elsevier Ltd. 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Durham University Library, Stockton Road, Durham DH1 3LY, United Kingdom Tel : +44 (0)191 334 3042 | Fax : +44 (0)191 334 2971 https://dro.dur.ac.uk 1 Terrestrial and submarine evidence for the extent and timing of the Last 2 Glacial Maximum and the onset of deglaciation on the maritime-Antarctic 3 and sub-Antarctic islands 4 5 Dominic A. Hodgsona*, Alastair G. C. Grahamb*, Stephen J. Robertsa, Michael J. Bentleyc, Colm Ó 6 Cofaighc, Elie Verleyend, Wim Vyvermand, Vincent Jomellie, Vincent Favierf, Daniel Brunsteine, 7 Deborah Verfaillief, Eric A. Colhoung, Krystyna M. Saundersh, Patricia M. Selkirki, Andrew 8 Mackintoshj, David W. Heddingk, Werner Nell, Kevin Hallm, Matt S. McGlonen, Nathalie Van der 9 Putteno, William A. Dickensa, James A. Smitha 10 11 12 13 a British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, 14 Cambridge, CB3 0ET, UK. 15 bDepartment of Geography, College of Life and Environmental Sciences, University of Exeter, 16 Amory Building, Rennes Drive, Exeter, EX4 4RJ, UK. 17 c Department of Geography, Durham University, South Rd, Durham DH1 3LE, UK. 18 d Laboratory for Protistology and Aquatic Ecology, Biology Department, Ghent University, Krijgslaan 19 281–S8, 9000 Ghent, Belgium. 20 e Université Paris 1 Panthéon Sorbonne–CNRS, Laboratoire de géographie physique, 1 place A. 21 Briand 92195, Meudon, France. 22 f Laboratoire de Glaciologie et de Géophysique de l’Environnement, LGGE, UJF–CNRS, UMR5183, 23 54 rue Molière, 38402 St Martin d’Hères, France. 24 g School of Environmental and Life Sciences The University of Newcastle NSW 2308 Australia. 25 h Institute of Geography and the Oeschger Centre for Climate Change Research, University of Bern, 26 Bern, Erlachstrasse 9, Trakt 3, 3012 Switzerland. 27 i Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia 28 jAntarctic Research Centre, Victoria University of Wellington, Wellington 6012, New Zealand. 29 k Department of Geography, University of South Africa, Florida Campus, Private Bag X6, Florida, 30 1710, South Africa 31 l Department of Geography and Environmental Science, University of Fort Hare, Alice campus 32 Private Bag X1314, Alice, 5700, South Africa. 33 m Geography Programme, University of Northern British Columbia, 3333 University Way, Prince 34 George, BC, Canada V2N 479. 35 n Landcare Research, PO Box 40, Lincoln 7640, New Zealand. 36 o Department of Geology, Lund University, Sölvegatan 12, SE–223 62 Lund, Sweden. 1 37 Corresponding author: 38 D.A. Hodgson, [email protected] 39 * These authors contributed equally to this work 40 41 Abstract 42 43 This paper is the maritime and sub–Antarctic contribution to the Scientific Committee for Antarctic 44 Research (SCAR) Past Antarctic Ice Sheet Dynamics (PAIS) community Antarctic Ice Sheet 45 reconstruction. The overarching aim for all sectors of Antarctica was to reconstruct the Last Glacial 46 Maximum (LGM) ice sheet extent and thickness, and map the subsequent deglaciation in a series of 47 approximately 2000–5000 year time slices. However, our review of the literature found surprisingly 48 few high quality chronological constraints on changing glacier extents on these timescales in the 49 maritime and sub–Antarctic sector. Therefore, in this paper we focus on an assessment of the 50 terrestrial and offshore evidence for the LGM ice extent, establishing minimum ages for the onset of 51 deglaciation, and separating evidence of deglaciation from the LGM limits from those associated with 52 later Holocene glacier fluctuations. Evidence included geomorphological descriptions of glacial 53 landscapes, radiocarbon dated basal peat and lake sediment deposits, cosmogenic isotope ages of 54 glacial features and molecular biological data. We propose a classification of the glacial history of the 55 maritime and sub–Antarctic islands based on this assembled evidence. These include: (Type I) islands 56 which accumulated little or no LGM ice; (Type II) islands with a limited LGM ice extent but evidence 57 of extensive earlier continental shelf glaciations; (Type III) seamounts and volcanoes unlikely to have 58 accumulated significant LGM ice cover; (Type IV) islands on shallow shelves with both terrestrial 59 and submarine evidence of LGM (and/or earlier) ice expansion; (Type V) Islands north of the 60 Antarctic Polar Front with terrestrial evidence of LGM ice expansion; and (Type VI) islands with no 61 data. Finally, we review the climatological and geomorphological settings that separate the 62 glaciological history of the islands within this classification scheme. 63 2 64 1. Introduction 65 66 Reconstructing the Antarctic Ice Sheet through its Last Glacial Maximum (LGM) and post LGM 67 deglacial history is important for a number of reasons. Firstly, ice sheet modellers require field data 68 against which to constrain and test their models of ice sheet change. The recent development of a 69 practical approach to modelling grounding line dynamics (Schoof, 2007) has led to a new generation 70 of models (e.g. Pollard and DeConto, 2009) that require field constraints. Secondly, the most recent 71 millennia and centuries of ice sheet history provide data on the ‘trajectory’ of the ice sheet, which are 72 valuable for the initialisation of models. Thirdly, the use of recent satellite gravity measurements (e.g. 73 GRACE), and other geodetic data such as GPS, for ice sheet mass balance estimates requires an 74 understanding of glacial–isostatic adjustment (GIA). In the case of GRACE the satellite-pair cannot 75 distinguish between recent changes in the mass balance of the ice sheet, and those from the transfer of 76 mass in the mantle resulting from past ice sheet melting. This means that robust ice sheet 77 reconstructions are required to generate GIA corrections and it is these corrections that are regarded as 78 the greatest limiting factors for ice mass measurements from satellite gravity (King et al., 2012). It has 79 even been suggested that some mass estimates may be in error by as much as 100% (Chen et al., 80 2006). 81 82 Several decades of study have produced an impressive body of work on Antarctic Ice Sheet history. 83 There have been a number of attempts to synthesise the data but many of these have just focussed on 84 the LGM. A notable reconstruction has been that produced by Ivins and James (2005) which 85 attempted to provide time-slices of the ice sheet from the LGM to the present-day to use as the basis 86 of their GIA modelling. This ‘model’, termed IJ05, has been widely adopted by the satellite gravity 87 and GPS communities as the ice sheet reconstruction with which to underpin their GIA assessments. 88 The model, although a benchmark at the time, is now becoming a little out-of-date, with the 89 proliferation of data since the early 2000s, and is not fully comprehensive of the glacial geological 90 data available. 91 92 As a result, the Antarctic Climate Evolution (ACE) and subsequent Past Antarctic Ice Sheet Dynamics 93 (PAIS) programmes of the Scientific Committee for Antarctic Research (SCAR) proposed a co- 94 ordinated effort by the glacial geology community to develop a synthesis of Antarctic Ice Sheet 95 history. This paper covers the maritime and sub-Antarctic sector. Other sectors of the Antarctic Ice 96 Sheet, including the maritime Antarctic islands west of the Antarctic Peninsula, are described 97 elsewhere in this Special Issue. 98 99 Although the combined volume of the maritime and sub-Antarctic LGM glaciers has had a very 100 limited effect on global sea level, understanding past extent and timing of past glaciations in the sub- 3 101 Antarctic is important for a number of reasons. First, the maritime and sub-Antarctic glaciers have 102 been amongst the earliest ice masses to respond to recent rapid regional warming (e.g. Gordon et al., 103 2008; Cook et al., 2010) and therefore provide a sensitive indicator of interactions between Southern 104 Hemisphere climate and ice sheet stability. This interaction can, in turn, be used to provide boundary 105 conditions for various physical parameters in glaciological models, including those associated with 106 abrupt climate change and the terminal phases of ice sheet decay.