Oceanic and atmospheric forcing of early Holocene ice shelf retreat,George VI Ice Shelf,Antarctica Peninsula |
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| Institution: | 1. Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964, USA;2. Laboratoire des Sciences du Climat et de l''Environnement, L''Orme des Merisiers, CEA Saclay, 91 191 Gif sur Yvette, France;3. UMR 8148, GEOPS, Université Paris Sud, CNRS, 91405 Orsay Cedex, France;1. Centre for Geographical Studies - IGOT, Universidade de Lisboa, Lisbon, Portugal;2. Departmento de Matemática Aplicada, Universidad Politécnica de Madrid, Madrid, Spain;3. Department of Geography, Masaryk University, Brno, Czech Republic;4. Instituto Dom Luiz (IDL), Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal;5. Environmental Management Center, Mykolas Romeris University, Vilnius, Lithuania;6. Department of Geography, University of Oviedo, Oviedo, Spain;1. British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, UK;2. Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, P.O. Box 120161, D-27515 Bremerhaven, Germany;3. College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4RJ, UK;4. Institute for Geophysics and Geology, University of Leipzig, Talstrasse 35, D-04103 Leipzig, Germany;5. NERC Radiocarbon Facility (Environment), East Kilbride, UK;6. Department of Geosciences, University of Bremen, P.O. Box 330440, D-28334 Bremen, Germany |
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| Abstract: | We use lake sediment records from an epishelf lake on Alexander Island to provide a detailed picture of the Holocene history of George VI Ice Shelf (GVI-IS). Core analyses included; micropaleontology (diatoms/foraminifera), stable isotope (δ18O, δ13C), geochemistry (total organic carbon (TOC), total nitrogen (TN), C/N ratios) and grain-size analyses. These data provide robust evidence for one period of past ice shelf absence during the early Holocene. The timing of this period has been constrained by 10 AMS 14C dates performed on mono-specific foraminifera samples. These dates suggest that GVI-IS was absent between c 9600 cal yr BP and c 7730 cal yr BP. This early Holocene collapse immediately followed a period of maximum Holocene warmth that is recorded in some Antarctic ice cores and coincides with an influx of warmer ocean water onto the western Antarctic Peninsula (AP) shelf at c 9000 cal yr BP. The absence of a currently extant ice shelf during this time interval suggests that early Holocene ocean-atmosphere variability in the AP was greater than that measured in recent decades. |
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