East Antarctic Ice Sheet variability in the central Transantarctic Mountains since the mid Miocene
<p>The response of the East Antarctic Ice Sheet to warmer-than-present climate conditions has direct implications for projections of future sea level, ocean circulation, and global radiative forcing. Nonetheless, it remains uncertain whether the ice sheet is likely to undergo net loss due to a...
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Copernicus Publications
2025-01-01
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| Series: | Climate of the Past |
| Online Access: | https://cp.copernicus.org/articles/21/145/2025/cp-21-145-2025.pdf |
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| author | G. R. M. Bromley G. R. M. Bromley G. Balco G. Balco M. S. Jackson A. Balter-Kennedy A. Balter-Kennedy H. Thomas |
| author_facet | G. R. M. Bromley G. R. M. Bromley G. Balco G. Balco M. S. Jackson A. Balter-Kennedy A. Balter-Kennedy H. Thomas |
| author_sort | G. R. M. Bromley |
| collection | DOAJ |
| description | <p>The response of the East Antarctic Ice Sheet to warmer-than-present climate conditions has direct implications for projections of future sea level, ocean circulation, and global radiative forcing. Nonetheless, it remains uncertain whether the ice sheet is likely to undergo net loss due to amplified melting coupled with dynamic instabilities or whether such losses will be balanced, or even offset, by enhanced accumulation under a higher-precipitation regime. The glacial depositional record from the central Transantarctic Mountains (TAM) provides a robust geologic means to reconstruct the past behaviour of the East Antarctic Ice Sheet, including during periods thought to have been warmer than today, such as the mid-Pliocene Warm Period (<span class="inline-formula">∼3.3</span>–3.0 Ma). This study describes a new surface-exposure-dated moraine record from Otway Massif in the central TAM spanning the last <span class="inline-formula">∼9</span> Myr and synthesises these data in the context of previously published moraine chronologies constrained with cosmogenic nuclides. The resulting record, although fragmentary, represents the majority of direct and unambiguous terrestrial evidence for the existence and size of the East Antarctic Ice Sheet during the last 14 Myr, and it thus provides new insight into the long-term relationship between the ice sheet and global climate. At face value, the existing TAM moraine record does not exhibit a clear signature of the mid-Pliocene Warm Period, thus precluding a definitive verdict on the East Antarctic Ice Sheet's response to this event. In contrast, an apparent hiatus in moraine deposition both at Otway Massif and the neighbouring Roberts Massif suggests that the ice sheet surface in the central TAM was potentially lower than present during the late Miocene and earliest Pliocene.</p> |
| format | Article |
| id | doaj-art-472fa4b4c39746189c7c6d09e800a0af |
| institution | Kabale University |
| issn | 1814-9324 1814-9332 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Climate of the Past |
| spelling | doaj-art-472fa4b4c39746189c7c6d09e800a0af2025-01-21T07:46:14ZengCopernicus PublicationsClimate of the Past1814-93241814-93322025-01-012114516010.5194/cp-21-145-2025East Antarctic Ice Sheet variability in the central Transantarctic Mountains since the mid MioceneG. R. M. Bromley0G. R. M. Bromley1G. Balco2G. Balco3M. S. Jackson4A. Balter-Kennedy5A. Balter-Kennedy6H. Thomas7Geography, University of Galway, Galway, H91 TK33, IrelandClimate Change Institute, University of Maine, Orono, Maine 04469, USABerkeley Geochronology Center, Berkeley, California 94709, USALawrence Livermore National Laboratory, Livermore, California 94550, USAGeography, Trinity College Dublin, Dublin, D02 PN40, IrelandClimate Change Institute, University of Maine, Orono, Maine 04469, USASchool of Earth and Climate Sciences, University of Maine, Orono, Maine 04469, USASchool of Earth and Climate Sciences, University of Maine, Orono, Maine 04469, USA<p>The response of the East Antarctic Ice Sheet to warmer-than-present climate conditions has direct implications for projections of future sea level, ocean circulation, and global radiative forcing. Nonetheless, it remains uncertain whether the ice sheet is likely to undergo net loss due to amplified melting coupled with dynamic instabilities or whether such losses will be balanced, or even offset, by enhanced accumulation under a higher-precipitation regime. The glacial depositional record from the central Transantarctic Mountains (TAM) provides a robust geologic means to reconstruct the past behaviour of the East Antarctic Ice Sheet, including during periods thought to have been warmer than today, such as the mid-Pliocene Warm Period (<span class="inline-formula">∼3.3</span>–3.0 Ma). This study describes a new surface-exposure-dated moraine record from Otway Massif in the central TAM spanning the last <span class="inline-formula">∼9</span> Myr and synthesises these data in the context of previously published moraine chronologies constrained with cosmogenic nuclides. The resulting record, although fragmentary, represents the majority of direct and unambiguous terrestrial evidence for the existence and size of the East Antarctic Ice Sheet during the last 14 Myr, and it thus provides new insight into the long-term relationship between the ice sheet and global climate. At face value, the existing TAM moraine record does not exhibit a clear signature of the mid-Pliocene Warm Period, thus precluding a definitive verdict on the East Antarctic Ice Sheet's response to this event. In contrast, an apparent hiatus in moraine deposition both at Otway Massif and the neighbouring Roberts Massif suggests that the ice sheet surface in the central TAM was potentially lower than present during the late Miocene and earliest Pliocene.</p>https://cp.copernicus.org/articles/21/145/2025/cp-21-145-2025.pdf |
| spellingShingle | G. R. M. Bromley G. R. M. Bromley G. Balco G. Balco M. S. Jackson A. Balter-Kennedy A. Balter-Kennedy H. Thomas East Antarctic Ice Sheet variability in the central Transantarctic Mountains since the mid Miocene Climate of the Past |
| title | East Antarctic Ice Sheet variability in the central Transantarctic Mountains since the mid Miocene |
| title_full | East Antarctic Ice Sheet variability in the central Transantarctic Mountains since the mid Miocene |
| title_fullStr | East Antarctic Ice Sheet variability in the central Transantarctic Mountains since the mid Miocene |
| title_full_unstemmed | East Antarctic Ice Sheet variability in the central Transantarctic Mountains since the mid Miocene |
| title_short | East Antarctic Ice Sheet variability in the central Transantarctic Mountains since the mid Miocene |
| title_sort | east antarctic ice sheet variability in the central transantarctic mountains since the mid miocene |
| url | https://cp.copernicus.org/articles/21/145/2025/cp-21-145-2025.pdf |
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