Obliquity-paced Pliocene West Antarctic ice sheet oscillations
Thirty years after oxygen isotope records from microfossils 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...
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ftharvardudash:oai:dash.harvard.edu:1/32095402 2023-05-15T13:51:19+02:00 Obliquity-paced Pliocene West Antarctic ice sheet oscillations Naish, T Huybers, Peter John 2009 application/pdf http://nrs.harvard.edu/urn-3:HUL.InstRepos:32095402 https://doi.org/10.1038/nature07867 en_US eng Nature Publishing Group doi:10.1038/nature07867 Nature Quick submit: 2016-01-29T17:21:07-05:00 Naish, T., Peter Huybers, et al. 2009. Obliquity-paced Pliocene West Antarctic ice sheet oscillations. Nature 458: 322-328. 0028-0836 http://nrs.harvard.edu/urn-3:HUL.InstRepos:32095402 Nash et al Journal Article 2009 ftharvardudash https://doi.org/10.1038/nature07867 2022-04-05T11:47:02Z Thirty years after oxygen isotope records from microfossils 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 marine-based West Antarctic ice sheet (WAIS) during the 'warmer-than-present' early-Pliocene epoch (approx5–3 Myr 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 600 m of the AND-1B sediment core recovered from beneath the northwest part of the Ross ice shelf by the ANDRILL programme and demonstrate well-dated, approx40-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 approx3 °C warmer than today4 and atmospheric CO2 concentration was as high as approx400 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 +7 m in equivalent sea level associated with the loss of the WAIS and up to +3 m in equivalent sea level from the East Antarctic ice sheet, in response to ocean-induced melting 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 melt8 under conditions of elevated CO2. Earth and Planetary Sciences Version of Record Article in Journal/Newspaper Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Ross Ice Shelf Sea ice Harvard University: DASH - Digital Access to Scholarship at Harvard Antarctic East Antarctic Ice Sheet Ross Ice Shelf The Antarctic West Antarctic Ice Sheet Nature 458 7236 322 328 |
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Harvard University: DASH - Digital Access to Scholarship at Harvard |
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English |
description |
Thirty years after oxygen isotope records from microfossils 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 marine-based West Antarctic ice sheet (WAIS) during the 'warmer-than-present' early-Pliocene epoch (approx5–3 Myr 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 600 m of the AND-1B sediment core recovered from beneath the northwest part of the Ross ice shelf by the ANDRILL programme and demonstrate well-dated, approx40-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 approx3 °C warmer than today4 and atmospheric CO2 concentration was as high as approx400 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 +7 m in equivalent sea level associated with the loss of the WAIS and up to +3 m in equivalent sea level from the East Antarctic ice sheet, in response to ocean-induced melting 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 melt8 under conditions of elevated CO2. Earth and Planetary Sciences Version of Record |
format |
Article in Journal/Newspaper |
author |
Naish, T Huybers, Peter John |
spellingShingle |
Naish, T Huybers, Peter John Obliquity-paced Pliocene West Antarctic ice sheet oscillations |
author_facet |
Naish, T Huybers, Peter John |
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 |
Nature Publishing Group |
publishDate |
2009 |
url |
http://nrs.harvard.edu/urn-3:HUL.InstRepos:32095402 https://doi.org/10.1038/nature07867 |
geographic |
Antarctic East Antarctic Ice Sheet Ross Ice Shelf The Antarctic West Antarctic Ice Sheet |
geographic_facet |
Antarctic East Antarctic Ice Sheet Ross Ice Shelf The Antarctic West Antarctic Ice Sheet |
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_relation |
doi:10.1038/nature07867 Nature Quick submit: 2016-01-29T17:21:07-05:00 Naish, T., Peter Huybers, et al. 2009. Obliquity-paced Pliocene West Antarctic ice sheet oscillations. Nature 458: 322-328. 0028-0836 http://nrs.harvard.edu/urn-3:HUL.InstRepos:32095402 |
op_rights |
Nash et al |
op_doi |
https://doi.org/10.1038/nature07867 |
container_title |
Nature |
container_volume |
458 |
container_issue |
7236 |
container_start_page |
322 |
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328 |
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1766255133551755264 |