A dynamic early East Antarctic Ice Sheet suggested by ice-covered fjord landscapes
The first Cenozoic ice sheets initiated in Antarctica from theGamburtsev Subglacial Mountains and other highlands as a resultof rapid global cooling 34 million years ago. In the subsequent 20million years, at a time of declining atmospheric carbon dioxideconcentrations and an evolving Antarctic circ...
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ftunivtasecite:oai:ecite.utas.edu.au:75883 2023-05-15T14:02:30+02:00 A dynamic early East Antarctic Ice Sheet suggested by ice-covered fjord landscapes Young, DA Wright, AP Roberts, JL Warner, RC Young, NW Greenbaum, JS Schroeder, DM Holt, JW Sugden, DE Blankenship, DD van Ommen, TD Siegert, MJ 2011 application/pdf https://doi.org/10.1038/nature10114 http://www.ncbi.nlm.nih.gov/pubmed/21637255 http://ecite.utas.edu.au/75883 en eng Nature Publishing Group http://ecite.utas.edu.au/75883/1/2011 - Nature - Young - ICECAP fjords.pdf http://dx.doi.org/10.1038/nature10114 Young, DA and Wright, AP and Roberts, JL and Warner, RC and Young, NW and Greenbaum, JS and Schroeder, DM and Holt, JW and Sugden, DE and Blankenship, DD and van Ommen, TD and Siegert, MJ, A dynamic early East Antarctic Ice Sheet suggested by ice-covered fjord landscapes, Nature, 474, (7349) pp. 72-75. ISSN 0028-0836 (2011) [Refereed Article] http://www.ncbi.nlm.nih.gov/pubmed/21637255 http://ecite.utas.edu.au/75883 Earth Sciences Physical Geography and Environmental Geoscience Glaciology Refereed Article PeerReviewed 2011 ftunivtasecite https://doi.org/10.1038/nature10114 2019-12-13T21:42:25Z The first Cenozoic ice sheets initiated in Antarctica from theGamburtsev Subglacial Mountains and other highlands as a resultof rapid global cooling 34 million years ago. In the subsequent 20million years, at a time of declining atmospheric carbon dioxideconcentrations and an evolving Antarctic circumpolar current,sedimentary sequence interpretation and numerical modellingsuggest that cyclical periods of ice-sheet expansion to the continentalmargin, followed by retreat to the subglacial highlands, occurred upto thirty times. These fluctuations were paced by orbital changes andwere a major influence on global sea levels. Ice-sheet models showthat the nature of such oscillations is critically dependent on thepattern and extent of Antarctic topographic lowlands. Here we showthat the basal topography of the Aurora Subglacial Basin of EastAntarctica, at present overlain by 24.5km of ice, is characterizedby a series of well-defined topographic channels within a mountainblock landscape. The identification of this fjord landscape, based onnew data from ice-penetrating radar, provides an improved understandingof the topography of the Aurora Subglacial Basin and itssurroundings, and reveals a complex surface sculpted by a successionof ice-sheet configurations substantially different from todays. Atdifferent stages during its fluctuations, the edge of the EastAntarcticIce Sheet lay pinned along the margins of the Aurora SubglacialBasin, the upland boundaries of which are currently above sea leveland the deepest parts of which are more than 1km below sea level.Although the timing of the channel incision remains uncertain, ourresults suggest that the fjord landscape was carved by at least two iceflowregimes of different scales and directions, each of which wouldhave over-deepened existing topographic depressions, reversingvalley floor slopes. Article in Journal/Newspaper Antarc* Antarctic Antarctica Ice Sheet eCite UTAS (University of Tasmania) Antarctic East Antarctic Ice Sheet Nature 474 7349 72 75 |
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Open Polar |
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eCite UTAS (University of Tasmania) |
op_collection_id |
ftunivtasecite |
language |
English |
topic |
Earth Sciences Physical Geography and Environmental Geoscience Glaciology |
spellingShingle |
Earth Sciences Physical Geography and Environmental Geoscience Glaciology Young, DA Wright, AP Roberts, JL Warner, RC Young, NW Greenbaum, JS Schroeder, DM Holt, JW Sugden, DE Blankenship, DD van Ommen, TD Siegert, MJ A dynamic early East Antarctic Ice Sheet suggested by ice-covered fjord landscapes |
topic_facet |
Earth Sciences Physical Geography and Environmental Geoscience Glaciology |
description |
The first Cenozoic ice sheets initiated in Antarctica from theGamburtsev Subglacial Mountains and other highlands as a resultof rapid global cooling 34 million years ago. In the subsequent 20million years, at a time of declining atmospheric carbon dioxideconcentrations and an evolving Antarctic circumpolar current,sedimentary sequence interpretation and numerical modellingsuggest that cyclical periods of ice-sheet expansion to the continentalmargin, followed by retreat to the subglacial highlands, occurred upto thirty times. These fluctuations were paced by orbital changes andwere a major influence on global sea levels. Ice-sheet models showthat the nature of such oscillations is critically dependent on thepattern and extent of Antarctic topographic lowlands. Here we showthat the basal topography of the Aurora Subglacial Basin of EastAntarctica, at present overlain by 24.5km of ice, is characterizedby a series of well-defined topographic channels within a mountainblock landscape. The identification of this fjord landscape, based onnew data from ice-penetrating radar, provides an improved understandingof the topography of the Aurora Subglacial Basin and itssurroundings, and reveals a complex surface sculpted by a successionof ice-sheet configurations substantially different from todays. Atdifferent stages during its fluctuations, the edge of the EastAntarcticIce Sheet lay pinned along the margins of the Aurora SubglacialBasin, the upland boundaries of which are currently above sea leveland the deepest parts of which are more than 1km below sea level.Although the timing of the channel incision remains uncertain, ourresults suggest that the fjord landscape was carved by at least two iceflowregimes of different scales and directions, each of which wouldhave over-deepened existing topographic depressions, reversingvalley floor slopes. |
format |
Article in Journal/Newspaper |
author |
Young, DA Wright, AP Roberts, JL Warner, RC Young, NW Greenbaum, JS Schroeder, DM Holt, JW Sugden, DE Blankenship, DD van Ommen, TD Siegert, MJ |
author_facet |
Young, DA Wright, AP Roberts, JL Warner, RC Young, NW Greenbaum, JS Schroeder, DM Holt, JW Sugden, DE Blankenship, DD van Ommen, TD Siegert, MJ |
author_sort |
Young, DA |
title |
A dynamic early East Antarctic Ice Sheet suggested by ice-covered fjord landscapes |
title_short |
A dynamic early East Antarctic Ice Sheet suggested by ice-covered fjord landscapes |
title_full |
A dynamic early East Antarctic Ice Sheet suggested by ice-covered fjord landscapes |
title_fullStr |
A dynamic early East Antarctic Ice Sheet suggested by ice-covered fjord landscapes |
title_full_unstemmed |
A dynamic early East Antarctic Ice Sheet suggested by ice-covered fjord landscapes |
title_sort |
dynamic early east antarctic ice sheet suggested by ice-covered fjord landscapes |
publisher |
Nature Publishing Group |
publishDate |
2011 |
url |
https://doi.org/10.1038/nature10114 http://www.ncbi.nlm.nih.gov/pubmed/21637255 http://ecite.utas.edu.au/75883 |
geographic |
Antarctic East Antarctic Ice Sheet |
geographic_facet |
Antarctic East Antarctic Ice Sheet |
genre |
Antarc* Antarctic Antarctica Ice Sheet |
genre_facet |
Antarc* Antarctic Antarctica Ice Sheet |
op_relation |
http://ecite.utas.edu.au/75883/1/2011 - Nature - Young - ICECAP fjords.pdf http://dx.doi.org/10.1038/nature10114 Young, DA and Wright, AP and Roberts, JL and Warner, RC and Young, NW and Greenbaum, JS and Schroeder, DM and Holt, JW and Sugden, DE and Blankenship, DD and van Ommen, TD and Siegert, MJ, A dynamic early East Antarctic Ice Sheet suggested by ice-covered fjord landscapes, Nature, 474, (7349) pp. 72-75. ISSN 0028-0836 (2011) [Refereed Article] http://www.ncbi.nlm.nih.gov/pubmed/21637255 http://ecite.utas.edu.au/75883 |
op_doi |
https://doi.org/10.1038/nature10114 |
container_title |
Nature |
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474 |
container_issue |
7349 |
container_start_page |
72 |
op_container_end_page |
75 |
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1766272783585640448 |