Antarctic marine ice-sheet retreat in the Ross Sea during th

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TitleAntarctic marine ice-sheet retreat in the Ross Sea during the early HoloceneAbstractGeological constraints on the timing of retreat of the Last Glacial Maximum (LGM) Antarctic Ice Sheets provide critical insights into the processes controlling marine-based ice-sheet retreat. The overdeepened, landward-sloping bathymetry of Antarctica's continental shelves is an ideal configuration for marine ice-sheet instability, with the potential for past and future ice-sheet collapse and accelerated sea-level rise. However, the chronology of retreat of the LGM ice sheet in the Ross Sea is largely constrained by imprecise radiocarbon chronology of bulk marine sediments or by coastal records that offer more reliable dating techniques but which may be influenced by local piedmont glaciers derived from East Antarctic outlet glaciers. Consequently, these coastal records may be ambiguous in the broader context of retreat in the central regions of the Ross Sea. Here, we present a sedimentary facies succession and foraminifera-based radiocarbon chronology from within the Ross Sea embayment that indicates glacial retreat and open-marine conditions to the east of Ross Island before 8.6 cal. (calibrated) kyr B.P., at least 1 k.y. earlier than indicated by terrestrial records in McMurdo Sound. Comparing these data to new modeling experiments, we hypothesize that marine-based ice-sheet retreat was triggered by oceanic forcings along most of the Pacific Ocean coastline of Antarctica, but continued Holocene retreat into the inner shelf region of the Ross Sea occurred primarily as a consequence of bathymetric controls on marine ice-sheet instability. Copyright 2015 The Authors.AcknowledgementsSupport was provided by the Royal Society (New Zealand) Rutherford Discovery Fellowship (RDF-13-VUW-003), the New Zealand Ministry of Business, Innovation, and Employment (C05X1001), the Alfred Wegner Institute (PACES II), and the U.S. National Science Foundation Division of Polar Programs (grant PLR-0839108). The field work was supported by the United States Antarctic Program and by Antarctica New Zealand. We thank three anonymous reviewers for their constructive comments that helped improve the paper.

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1st AuthorMcKay, R.AuthorMcKay, R.Golledge, N.Maas, S.Naish, T.Levy, R.Dunbar, G.Kuhn, G.Year2016JournalGeologyVolume44Number1Pages7/10/2017DOI10.1130/G37315.1URLhttps://www.scopus.com/inward/recor.....b7abd8a6fef4d4c60c6b0e420KeywordsBathymetryGlacial geologyGlaciersSea levelSubmarine geology, Accelerated sea-level riseAntarctic ice sheetsContinental shelvesIce-sheet retreatLast Glacial MaximumMarine conditionsModel experimentsSedimentary facies, Ice, geochronologyglacier retreatHoloceneice retreatice sheetLast Glacial Maximumradiocarbon dating, AntarcticaPacific OceanRoss SeaSouthern Ocean, Foraminifera, rank5

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TypeArticleCitationMcKay, R., Golledge, N., Maas, S., Naish, T., Levy, R., Dunbar, G. and Kuhn, G. (2016). Antarctic marine ice-sheet retreat in the Ross Sea during the early Holocene. Geology, 44(1): 7-10