Obliquity-paced Pliocene West Antarctic ice sheet oscillations
Thirty years after oxygen isotope records frommicrofossils deposited in ocean sediments confirmed the hypothesis that variations in the Earth’s orbital geometry control the ice ages1, fundamental questions remain over the response of the Antarctic ice sheets to orbital cycles2. Furthermore, an under...
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2009
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ftunivnebraskali:oai:digitalcommons.unl.edu:geosciencefacpub-1186 2023-11-12T04:04:12+01:00 Obliquity-paced Pliocene West Antarctic ice sheet oscillations Naish, T. Powell, R. D. Levy, R. Wilson, G. Scherer, R. Talarico, F. Krissek, L. Niessen, F. Pompilio, M. Wilson, T. J. Carter, L. DeConto, R. Huybers, P. McKay, R. Pollard, D. Ross, J. Winter, D. Barrett, P. Browne, G. Cody, R. Cowan, E. A. Crampton, J. Dunbar, G. Dunbar, N. Florindo, F. Gebhardt, C. Graham, I. Hannah, M. Hansaraj, D. Harwood, David M. Helling, D. Henrys, S. Hinnov, L. Kuhn, G. Kyle, P. La¨ufer, A. Maffioli, P. Magens, D. Mandernack, K. McIntosh, W. Millan, C. Morin, R. Ohneiser, C. Paulsen, T. Persico, D. Raine, I. Reed, J. Riesselman, C. Sagnotti, L. Schmitt, D. Sjunneskog, C. Strong, P. Taviani, M. Vogel, S. Wilch, T. Williams, T. 2009-01-01T08:00:00Z application/pdf https://digitalcommons.unl.edu/geosciencefacpub/185 https://digitalcommons.unl.edu/context/geosciencefacpub/article/1186/viewcontent/Harwood_NATURE_2009_Obliquity_paced_Pliocene.pdf unknown DigitalCommons@University of Nebraska - Lincoln https://digitalcommons.unl.edu/geosciencefacpub/185 https://digitalcommons.unl.edu/context/geosciencefacpub/article/1186/viewcontent/Harwood_NATURE_2009_Obliquity_paced_Pliocene.pdf Papers in the Earth and Atmospheric Sciences Earth Sciences text 2009 ftunivnebraskali 2023-10-30T10:44:33Z Thirty years after oxygen isotope records frommicrofossils deposited in ocean sediments confirmed the hypothesis that variations in the Earth’s orbital geometry control the ice ages1, fundamental questions remain over the response of the Antarctic ice sheets to orbital cycles2. Furthermore, an understanding of the behaviour of the marinebased West Antarctic ice sheet (WAIS) during the ‘warmerthan- present’ early-Pliocene epoch ( ~5–3Myr ago) is needed to better constrain the possible range of ice-sheet behaviour in the context of future global warming3. Here we present a marine glacial record from the upper 600mof the AND-1B sediment core recovered from beneath the northwest part of the Ross ice shelf by the ANDRILL programme and demonstrate well-dated, ~40-kyr cyclic variations in ice-sheet extent linked to cycles in insolation influenced by changes in the Earth’s axial tilt (obliquity) during the Pliocene. Our data provide direct evidence for orbitally induced oscillations in the WAIS, which periodically collapsed, resulting in a switch from grounded ice, or ice shelves, to open waters in the Ross embayment when planetary temperatures were up to ~3 C warmer than today4 and atmospheric CO2 concentration was as high as ~400 p.p.m.v. (refs 5, 6). The evidence is consistent with a new ice-sheet/ice-shelf model7 that simulates fluctuations in Antarctic ice volume of up to +7min equivalent sea level associated with the loss of the WAIS and up to+3min equivalent sea level from the EastAntarctic ice sheet, in response to ocean-inducedmelting paced by obliquity.During interglacial times, diatomaceous sediments indicate high surface-water productivity, minimal summer sea ice and air temperatures above freezing, suggesting an additional influence of surface melt 8 under conditions of elevated CO2. Text Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Ross Ice Shelf Sea ice University of Nebraska-Lincoln: DigitalCommons@UNL Antarctic The Antarctic West Antarctic Ice Sheet Ross Ice Shelf |
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Open Polar |
collection |
University of Nebraska-Lincoln: DigitalCommons@UNL |
op_collection_id |
ftunivnebraskali |
language |
unknown |
topic |
Earth Sciences |
spellingShingle |
Earth Sciences Naish, T. Powell, R. D. Levy, R. Wilson, G. Scherer, R. Talarico, F. Krissek, L. Niessen, F. Pompilio, M. Wilson, T. J. Carter, L. DeConto, R. Huybers, P. McKay, R. Pollard, D. Ross, J. Winter, D. Barrett, P. Browne, G. Cody, R. Cowan, E. A. Crampton, J. Dunbar, G. Dunbar, N. Florindo, F. Gebhardt, C. Graham, I. Hannah, M. Hansaraj, D. Harwood, David M. Helling, D. Henrys, S. Hinnov, L. Kuhn, G. Kyle, P. La¨ufer, A. Maffioli, P. Magens, D. Mandernack, K. McIntosh, W. Millan, C. Morin, R. Ohneiser, C. Paulsen, T. Persico, D. Raine, I. Reed, J. Riesselman, C. Sagnotti, L. Schmitt, D. Sjunneskog, C. Strong, P. Taviani, M. Vogel, S. Wilch, T. Williams, T. Obliquity-paced Pliocene West Antarctic ice sheet oscillations |
topic_facet |
Earth Sciences |
description |
Thirty years after oxygen isotope records frommicrofossils deposited in ocean sediments confirmed the hypothesis that variations in the Earth’s orbital geometry control the ice ages1, fundamental questions remain over the response of the Antarctic ice sheets to orbital cycles2. Furthermore, an understanding of the behaviour of the marinebased West Antarctic ice sheet (WAIS) during the ‘warmerthan- present’ early-Pliocene epoch ( ~5–3Myr ago) is needed to better constrain the possible range of ice-sheet behaviour in the context of future global warming3. Here we present a marine glacial record from the upper 600mof the AND-1B sediment core recovered from beneath the northwest part of the Ross ice shelf by the ANDRILL programme and demonstrate well-dated, ~40-kyr cyclic variations in ice-sheet extent linked to cycles in insolation influenced by changes in the Earth’s axial tilt (obliquity) during the Pliocene. Our data provide direct evidence for orbitally induced oscillations in the WAIS, which periodically collapsed, resulting in a switch from grounded ice, or ice shelves, to open waters in the Ross embayment when planetary temperatures were up to ~3 C warmer than today4 and atmospheric CO2 concentration was as high as ~400 p.p.m.v. (refs 5, 6). The evidence is consistent with a new ice-sheet/ice-shelf model7 that simulates fluctuations in Antarctic ice volume of up to +7min equivalent sea level associated with the loss of the WAIS and up to+3min equivalent sea level from the EastAntarctic ice sheet, in response to ocean-inducedmelting paced by obliquity.During interglacial times, diatomaceous sediments indicate high surface-water productivity, minimal summer sea ice and air temperatures above freezing, suggesting an additional influence of surface melt 8 under conditions of elevated CO2. |
format |
Text |
author |
Naish, T. Powell, R. D. Levy, R. Wilson, G. Scherer, R. Talarico, F. Krissek, L. Niessen, F. Pompilio, M. Wilson, T. J. Carter, L. DeConto, R. Huybers, P. McKay, R. Pollard, D. Ross, J. Winter, D. Barrett, P. Browne, G. Cody, R. Cowan, E. A. Crampton, J. Dunbar, G. Dunbar, N. Florindo, F. Gebhardt, C. Graham, I. Hannah, M. Hansaraj, D. Harwood, David M. Helling, D. Henrys, S. Hinnov, L. Kuhn, G. Kyle, P. La¨ufer, A. Maffioli, P. Magens, D. Mandernack, K. McIntosh, W. Millan, C. Morin, R. Ohneiser, C. Paulsen, T. Persico, D. Raine, I. Reed, J. Riesselman, C. Sagnotti, L. Schmitt, D. Sjunneskog, C. Strong, P. Taviani, M. Vogel, S. Wilch, T. Williams, T. |
author_facet |
Naish, T. Powell, R. D. Levy, R. Wilson, G. Scherer, R. Talarico, F. Krissek, L. Niessen, F. Pompilio, M. Wilson, T. J. Carter, L. DeConto, R. Huybers, P. McKay, R. Pollard, D. Ross, J. Winter, D. Barrett, P. Browne, G. Cody, R. Cowan, E. A. Crampton, J. Dunbar, G. Dunbar, N. Florindo, F. Gebhardt, C. Graham, I. Hannah, M. Hansaraj, D. Harwood, David M. Helling, D. Henrys, S. Hinnov, L. Kuhn, G. Kyle, P. La¨ufer, A. Maffioli, P. Magens, D. Mandernack, K. McIntosh, W. Millan, C. Morin, R. Ohneiser, C. Paulsen, T. Persico, D. Raine, I. Reed, J. Riesselman, C. Sagnotti, L. Schmitt, D. Sjunneskog, C. Strong, P. Taviani, M. Vogel, S. Wilch, T. Williams, T. |
author_sort |
Naish, T. |
title |
Obliquity-paced Pliocene West Antarctic ice sheet oscillations |
title_short |
Obliquity-paced Pliocene West Antarctic ice sheet oscillations |
title_full |
Obliquity-paced Pliocene West Antarctic ice sheet oscillations |
title_fullStr |
Obliquity-paced Pliocene West Antarctic ice sheet oscillations |
title_full_unstemmed |
Obliquity-paced Pliocene West Antarctic ice sheet oscillations |
title_sort |
obliquity-paced pliocene west antarctic ice sheet oscillations |
publisher |
DigitalCommons@University of Nebraska - Lincoln |
publishDate |
2009 |
url |
https://digitalcommons.unl.edu/geosciencefacpub/185 https://digitalcommons.unl.edu/context/geosciencefacpub/article/1186/viewcontent/Harwood_NATURE_2009_Obliquity_paced_Pliocene.pdf |
geographic |
Antarctic The Antarctic West Antarctic Ice Sheet Ross Ice Shelf |
geographic_facet |
Antarctic The Antarctic West Antarctic Ice Sheet Ross Ice Shelf |
genre |
Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Ross Ice Shelf Sea ice |
genre_facet |
Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Ross Ice Shelf Sea ice |
op_source |
Papers in the Earth and Atmospheric Sciences |
op_relation |
https://digitalcommons.unl.edu/geosciencefacpub/185 https://digitalcommons.unl.edu/context/geosciencefacpub/article/1186/viewcontent/Harwood_NATURE_2009_Obliquity_paced_Pliocene.pdf |
_version_ |
1782341031647248384 |