Antarctic glacial history from numerical models and continental margin sediments


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phuybrechts [ at ] awi-bremerhaven.de

Abstract

The climate record of glacially-transported sediments in prograded wedges around the Antarctic outer continental shelf, and theirderivatives in continental rise drifts, may be combined to produce an Antarctic glacial history, using numerical models of ice sheetresponse to temperature and sea-level change. Examination of published models suggest several preliminary conclusions about ice sheethistory. The ice sheet's present high sensitivity to sea-level change at short (orbital) periods was developed gradually as its size increased,replacing a declining sensitivity to temperature. Models suggest that the ice sheet grew abruptly to 40% (or possibly more) of its presentsize at the Eocene-Oligocene boundary, mainly as a result of its own temperature sensitivity. A large but more gradual mid-Miocenechange was externally driven, probably by development of the Antarctic Circumpolar Current (ACC) and Polar Front, provided that a fewmillion years' delay can be explained. The Oligocene ice sheet varied considerably in size and areal extent, but the late Miocene ice sheetwas more stable, though significantly warmer than today's. This difference probably relates to the confining effect of the Antarcticcontinental margin. Present-day numerical models of ice sheet development are sufficient to guide current sampling plans, but sea-iceformation, polar wander, basal topography and ice streaming can be identified as factors meriting additional modelling effort in the future.



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ISI/Scopus peer-reviewed
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Eprint ID
3665
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Barker, P. F. , Barrett, P. J. , Cooper, A. K. and Huybrechts, P. (1999): Antarctic glacial history from numerical models and continental margin sediments , Palaeogeography, Palaeoclimatology, Palaeoecology, 150 , pp. 247-267 .


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