Changing Southern Ocean palaeocirculation and effects on global climate
Southern Ocean palaeocirculation is clearly related to the formation of a continental ice sheet on Antarctica and the opening of gateways between Antarctica and the Australian and South American continents. Palaeoenvironmental proxy records from Southern Ocean sediment cores suggest ice growth on An...
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crcambridgeupr:10.1017/s0954102004002202 2024-06-23T07:46:14+00:00 Changing Southern Ocean palaeocirculation and effects on global climate MACKENSEN, ANDREAS 2004 http://dx.doi.org/10.1017/s0954102004002202 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102004002202 en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Antarctic Science volume 16, issue 4, page 369-386 ISSN 0954-1020 1365-2079 journal-article 2004 crcambridgeupr https://doi.org/10.1017/s0954102004002202 2024-06-12T04:02:19Z Southern Ocean palaeocirculation is clearly related to the formation of a continental ice sheet on Antarctica and the opening of gateways between Antarctica and the Australian and South American continents. Palaeoenvironmental proxy records from Southern Ocean sediment cores suggest ice growth on Antarctica beginning by at least 40 million years (Ma) ago, and the opening of Tasmania–Antarctic and Drake Passages to deep-water flow around 34 and 31 ± 2 Ma, respectively. So, the Eocene/Oligocene transition appears to mark the initiation of the Antarctic Circumpolar Current and thus the onset of thermal isolation of Antarctica with a first major ice volume growth on East Antarctic. There is no evidence for a significant cooling of the deep ocean associated with this rapid (< 350 000 years) continental ice build-up. After a long phase with frequent ice sheets growing and decaying, in the middle Miocene at about 14 Ma, a re-establishment of an ice sheet on East Antarctica and the Pacific margin of West Antarctica was associated with an increased southern bottom water formation, and a slight cooling of the deep ocean, but with no permanent drop in atmospheric p CO 2 . During the late Pleistocene on orbital time scales a temporal correlation between changes in atmospheric p CO 2 and proxy records of deep ocean temperatures, continental ice volume, sea ice extension, and deep-water nutrient contents is documented. I discuss hypotheses that call for a dominant control of glacial to interglacial atmospheric p CO 2 variations by Southern Ocean circulation dynamics. Millennial to centennial climate variability is a global feature, but there is contrasting evidence from various palaeoclimate archives that indicate both interhemispheric synchrony and asynchrony. The role of the Southern Ocean, however, in triggering or modulating climate variability on these time scales only recently received some attention and is not yet adequately investigated. Article in Journal/Newspaper Antarc* Antarctic Antarctic Science Antarctica East Antarctica Ice Sheet Sea ice Southern Ocean West Antarctica Cambridge University Press Antarctic Southern Ocean The Antarctic East Antarctica West Antarctica Pacific Antarctic Science 16 4 369 386 |
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Cambridge University Press |
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crcambridgeupr |
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English |
description |
Southern Ocean palaeocirculation is clearly related to the formation of a continental ice sheet on Antarctica and the opening of gateways between Antarctica and the Australian and South American continents. Palaeoenvironmental proxy records from Southern Ocean sediment cores suggest ice growth on Antarctica beginning by at least 40 million years (Ma) ago, and the opening of Tasmania–Antarctic and Drake Passages to deep-water flow around 34 and 31 ± 2 Ma, respectively. So, the Eocene/Oligocene transition appears to mark the initiation of the Antarctic Circumpolar Current and thus the onset of thermal isolation of Antarctica with a first major ice volume growth on East Antarctic. There is no evidence for a significant cooling of the deep ocean associated with this rapid (< 350 000 years) continental ice build-up. After a long phase with frequent ice sheets growing and decaying, in the middle Miocene at about 14 Ma, a re-establishment of an ice sheet on East Antarctica and the Pacific margin of West Antarctica was associated with an increased southern bottom water formation, and a slight cooling of the deep ocean, but with no permanent drop in atmospheric p CO 2 . During the late Pleistocene on orbital time scales a temporal correlation between changes in atmospheric p CO 2 and proxy records of deep ocean temperatures, continental ice volume, sea ice extension, and deep-water nutrient contents is documented. I discuss hypotheses that call for a dominant control of glacial to interglacial atmospheric p CO 2 variations by Southern Ocean circulation dynamics. Millennial to centennial climate variability is a global feature, but there is contrasting evidence from various palaeoclimate archives that indicate both interhemispheric synchrony and asynchrony. The role of the Southern Ocean, however, in triggering or modulating climate variability on these time scales only recently received some attention and is not yet adequately investigated. |
format |
Article in Journal/Newspaper |
author |
MACKENSEN, ANDREAS |
spellingShingle |
MACKENSEN, ANDREAS Changing Southern Ocean palaeocirculation and effects on global climate |
author_facet |
MACKENSEN, ANDREAS |
author_sort |
MACKENSEN, ANDREAS |
title |
Changing Southern Ocean palaeocirculation and effects on global climate |
title_short |
Changing Southern Ocean palaeocirculation and effects on global climate |
title_full |
Changing Southern Ocean palaeocirculation and effects on global climate |
title_fullStr |
Changing Southern Ocean palaeocirculation and effects on global climate |
title_full_unstemmed |
Changing Southern Ocean palaeocirculation and effects on global climate |
title_sort |
changing southern ocean palaeocirculation and effects on global climate |
publisher |
Cambridge University Press (CUP) |
publishDate |
2004 |
url |
http://dx.doi.org/10.1017/s0954102004002202 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102004002202 |
geographic |
Antarctic Southern Ocean The Antarctic East Antarctica West Antarctica Pacific |
geographic_facet |
Antarctic Southern Ocean The Antarctic East Antarctica West Antarctica Pacific |
genre |
Antarc* Antarctic Antarctic Science Antarctica East Antarctica Ice Sheet Sea ice Southern Ocean West Antarctica |
genre_facet |
Antarc* Antarctic Antarctic Science Antarctica East Antarctica Ice Sheet Sea ice Southern Ocean West Antarctica |
op_source |
Antarctic Science volume 16, issue 4, page 369-386 ISSN 0954-1020 1365-2079 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1017/s0954102004002202 |
container_title |
Antarctic Science |
container_volume |
16 |
container_issue |
4 |
container_start_page |
369 |
op_container_end_page |
386 |
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1802644705008156672 |