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Address : 1Victoria University of Wellington, New Zealand; 2British Antarctic Survey, United Kingdom;3Northern Illinois University, United States
Celebration date : 28 Sunday September 2008
Author name : Naish, Tim1; Wolff, Eric2; Carter, Lionel1; McKay, Robert1; Powell, Ross3

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  • Article title : Antarctic climate evolution during the Quaternary (last 2.6 Ma) from continental margin, Southern Ocean and ice core records
    Article type : Paleontology and Stratigraphy
    Location : International Geological Congress,oslo 2008

    Fulltext :

    Here we present a picture of Antarctica’s Quaternary climate evolution, constructed from the upper the 600m of the ANDRILL Program’s McMurdo Ice Shelf sediment core - AND-1B, and discussed within the context of other Antarctic margin and southern ocean drillcore (ODP), and continental ice core records (Vostok, EPICA). The records show the long term evolution of the West Antarctic Ice Sheet (WAIS) from a small, dynamic, terrestrially-based feature during the Early Pliocene (5-3-Myr), through to its present large, cold and more persistent state (2.5-0-Myr). Well-dated, cyclic variations in the sediment cores link the volume of the Antarctic ice sheets, sea-ice extent, Antarctic bottom water production, and ocean circulation to orbital-scale climate cycles. We discuss evidence of a significant change in thermal regime in the Late Pliocene, coincident with a global cooling step in oxygen isotope records and onset of major northern hemisphere glaciations. At this time Antarctic ice sheets attained their present cold polar state; ephemeral terrestrially-based ice margins were replaced by marine termini and the development of ice shelves (e.g. Ross Ice Shelf). Interhemispheric coupling of polar ice sheets, controlled by northern hemisphere (NH) glacio-eustasy, accounts for much of the variability in Antarctic ice volume since 2.5-Myr. A further expansion of the WAIS concomitant with increased in NH ice volume occurred across the Mid-Pleistocene Climate Transition (MPT; 1-0.8-Myr), after which open-marine conditions have not occurred in the Ross Embayment.