Retreat of the East Antarctic ice sheet during the last glac

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TitleRetreat of the East Antarctic ice sheet during the last glacial terminationAbstractThe retreat of the East Antarctic ice sheet at the end of the last glacial period has been attributed to both sea-level rise and warming of the ocean at the margin of the ice sheet, but it has been challenging to test these hypotheses. Given the lack of constraints on the timing of retreat, it has been difficult to evaluate whether the East Antarctic ice sheet contributed to meltwater pulse 1a, an abrupt sea-level rise of approximately 20 m that occurred about 14,700 years ago. Here we use terrestrial exposure ages and marine sedimentological analyses to show that ice retreat in Mac. Robertson Land, East Antarctica, initiated about 14,000 years ago, became widespread about 12,000 years ago, and was completed by about 7,000 years ago. We use two models of different complexities to assess the forcing of the retreat. Our simulations suggest that, although the initial stage of retreat may have been forced by sea-level rise, the majority of the ice loss resulted from ocean warming at the onset of the Holocene epoch. In light of our age model we conclude that the East Antarctic ice sheet is unlikely to have been the source of meltwater pulse 1a, and, on the basis of our simulations, suggest that Antarctic ice sheets made an insignificant contribution to eustatic sea-level rise at this time. Copyright 2011 Macmillan Publishers Limited. All rights reserved.AcknowledgementsThe New Zealand team acknowledges financial support from VUW Foundation grants ARCCIM, ARCMORG and New Zealand FRST ANDRILL and ANZICE grants CO5X1001 and VICX0704. The US team thanks the scientific staff, Captain J. Borkowski and his ECO crew, and the Raytheon Polar Services staff who participated on cruise NBP0101. The marine work was supported by National Science Foundation grants OPP-9909367 to A.L., OPP-9909837 to R.D. and NSF-OPP grant 0732467 to E.D. The Australian team thanks the Australian Antarctic Division (AAS1071, 1332), Australian Institute of Nuclear Science and Engineering (03/048), Australian Research Council (DP0556728) and Macquarie University for logistic and financial support. We also thank staff at the Antarctic Marine Geology Research Facility at Florida State University, and T. Fanning, J. Pickard and T. Labrum for field assistance. K. Fleming provided modelled eustatic sea-level data. R. Peltier and R. Drummond provided both eustatic and relative sea-level data for the Mac. Robertson Land coast. B. Hall calibrated and interpreted 14 C ages from Taylor Valley.

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1st AuthorMackintosh, A.AuthorMackintosh, A.Golledge, N.Domack, E.Dunbar, R.Leventer, A.White, D.Pollard, D.Deconto, R.Fink, D.Zwartz, D.Gore, D.Lavoie, C.Year2011JournalNature GeoscienceVolume4Number3Pages195-202DOI10.1038/ngeo1061URLhttps://www.scopus.com/inward/recor.....39f3c8bb2190c1b44425e79b6Keywordsglacier retreatHolocenehypothesis testingice sheetLast Glacialmarine sedimentmeltwatersea level changesedimentologywarming, AntarcticaEast Antarctica, rank3

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TypeArticleCitationMackintosh, A., Golledge, N., Domack, E., Dunbar, R., Leventer, A., White, D., Pollard, D., Deconto, R., Fink, D., Zwartz, D., Gore, D. and Lavoie, C. (2011). Retreat of the East Antarctic ice sheet during the last glacial termination. Nature Geoscience, 4(3): 195-202IdentifierMackintosh2011Relevancerank3