Flow re-organization of the East Antarctic ice sheet across glacial cycles
Constraining the stability of the East Antarctic Ice Sheet (EAIS) over glacial-interglacial timescales is important to both understand its sea level contributions in the past and predict its future contributions in a warming world. Constraining how fast the EAIS can deliver ice to the ocean is as im...
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ftunivtexas:oai:repositories.lib.utexas.edu:2152/62592 2023-05-15T14:02:55+02:00 Flow re-organization of the East Antarctic ice sheet across glacial cycles Cavitte, Marie Genevieve P. Blankenship, Donald D Ghattas, Omar Quinn, Terrence M Sen, Mrinal K Siegert, Martin J Young, Duncan A 2017-08 application/pdf http://hdl.handle.net/2152/62592 https://doi.org/10.15781/T2ZK5633S en eng doi:10.15781/T2ZK5633S http://hdl.handle.net/2152/62592 Glaciology Ice-penetrating radar Isochrones Modeling South Pole Dome C Oldest Ice Thesis text 2017 ftunivtexas https://doi.org/10.15781/T2ZK5633S 2020-12-23T22:22:32Z Constraining the stability of the East Antarctic Ice Sheet (EAIS) over glacial-interglacial timescales is important to both understand its sea level contributions in the past and predict its future contributions in a warming world. Constraining how fast the EAIS can deliver ice to the ocean is as important as how much. Total volume fluctuations can be inferred through the use of nunatak exposure ages and ice core dating as well as through ice sheet modeling reconstructions of the Antarctic Ice Sheet as a whole. However, the EAIS’s ice volume fluctuations over long timescales such as 100-kyr glacial cycles and short spatial scales such as single ice flow catchment are less well known. I establish a method for dating internal reflections from ice-penetrating radar data between the Vostok and Dome C ice core sites, and determine the associated uncertainties in depth and age. I constrain the stability of two catchments of the EAIS through the use of internal stratigraphy from ice-penetrating radar, dated using correlated ice cores, combined with 1D ice flow models to reconstruct past accumulation rates. Here, I show that the ice catchment at the South Pole was highly active during the last glacial maximum while the ice dome/divide at Dome C was fairly stable during the entire last glacial cycle. Enhanced flow reaching South Pole implies the EAIS’s interior is much more susceptible to changes than previously thought. The absence of flow re-organization at Dome C for the last glacial maximum in contrast to South Pole shows that flow re-organization can vary from catchment to catchment. In addition, the stability of the Dome C region for the last 128 kyrs is highly promising for the retrieval of 1.5 million-year-old ice. 1D inversions of the deep radar isochrones interpreted above the subglacial relief of the Little Dome C (LDC) surface dome, ~30 km south of Dome C, predict several 1.5 million-year-old ice drilling sites. However, the complicated basal radar internal stratigraphy above the LDC and the presence of subglacial lakes complicate the task of choosing an ice core drill site. The EAIS-wide internal stratigraphy from the extensive modern ice-penetrating radar data now available over the EAIS have improved our understanding of its configuration and stability on multiple scales and timescales, and provide a foundation for understanding East Antarctica’s future role in global sea level change. Geological Sciences Thesis Antarc* Antarctic ice core Ice Sheet South pole South pole The University of Texas at Austin: Texas ScholarWorks Antarctic The Antarctic East Antarctic Ice Sheet South Pole |
institution |
Open Polar |
collection |
The University of Texas at Austin: Texas ScholarWorks |
op_collection_id |
ftunivtexas |
language |
English |
topic |
Glaciology Ice-penetrating radar Isochrones Modeling South Pole Dome C Oldest Ice |
spellingShingle |
Glaciology Ice-penetrating radar Isochrones Modeling South Pole Dome C Oldest Ice Cavitte, Marie Genevieve P. Flow re-organization of the East Antarctic ice sheet across glacial cycles |
topic_facet |
Glaciology Ice-penetrating radar Isochrones Modeling South Pole Dome C Oldest Ice |
description |
Constraining the stability of the East Antarctic Ice Sheet (EAIS) over glacial-interglacial timescales is important to both understand its sea level contributions in the past and predict its future contributions in a warming world. Constraining how fast the EAIS can deliver ice to the ocean is as important as how much. Total volume fluctuations can be inferred through the use of nunatak exposure ages and ice core dating as well as through ice sheet modeling reconstructions of the Antarctic Ice Sheet as a whole. However, the EAIS’s ice volume fluctuations over long timescales such as 100-kyr glacial cycles and short spatial scales such as single ice flow catchment are less well known. I establish a method for dating internal reflections from ice-penetrating radar data between the Vostok and Dome C ice core sites, and determine the associated uncertainties in depth and age. I constrain the stability of two catchments of the EAIS through the use of internal stratigraphy from ice-penetrating radar, dated using correlated ice cores, combined with 1D ice flow models to reconstruct past accumulation rates. Here, I show that the ice catchment at the South Pole was highly active during the last glacial maximum while the ice dome/divide at Dome C was fairly stable during the entire last glacial cycle. Enhanced flow reaching South Pole implies the EAIS’s interior is much more susceptible to changes than previously thought. The absence of flow re-organization at Dome C for the last glacial maximum in contrast to South Pole shows that flow re-organization can vary from catchment to catchment. In addition, the stability of the Dome C region for the last 128 kyrs is highly promising for the retrieval of 1.5 million-year-old ice. 1D inversions of the deep radar isochrones interpreted above the subglacial relief of the Little Dome C (LDC) surface dome, ~30 km south of Dome C, predict several 1.5 million-year-old ice drilling sites. However, the complicated basal radar internal stratigraphy above the LDC and the presence of subglacial lakes complicate the task of choosing an ice core drill site. The EAIS-wide internal stratigraphy from the extensive modern ice-penetrating radar data now available over the EAIS have improved our understanding of its configuration and stability on multiple scales and timescales, and provide a foundation for understanding East Antarctica’s future role in global sea level change. Geological Sciences |
author2 |
Blankenship, Donald D Ghattas, Omar Quinn, Terrence M Sen, Mrinal K Siegert, Martin J Young, Duncan A |
format |
Thesis |
author |
Cavitte, Marie Genevieve P. |
author_facet |
Cavitte, Marie Genevieve P. |
author_sort |
Cavitte, Marie Genevieve P. |
title |
Flow re-organization of the East Antarctic ice sheet across glacial cycles |
title_short |
Flow re-organization of the East Antarctic ice sheet across glacial cycles |
title_full |
Flow re-organization of the East Antarctic ice sheet across glacial cycles |
title_fullStr |
Flow re-organization of the East Antarctic ice sheet across glacial cycles |
title_full_unstemmed |
Flow re-organization of the East Antarctic ice sheet across glacial cycles |
title_sort |
flow re-organization of the east antarctic ice sheet across glacial cycles |
publishDate |
2017 |
url |
http://hdl.handle.net/2152/62592 https://doi.org/10.15781/T2ZK5633S |
geographic |
Antarctic The Antarctic East Antarctic Ice Sheet South Pole |
geographic_facet |
Antarctic The Antarctic East Antarctic Ice Sheet South Pole |
genre |
Antarc* Antarctic ice core Ice Sheet South pole South pole |
genre_facet |
Antarc* Antarctic ice core Ice Sheet South pole South pole |
op_relation |
doi:10.15781/T2ZK5633S http://hdl.handle.net/2152/62592 |
op_doi |
https://doi.org/10.15781/T2ZK5633S |
_version_ |
1766273356647104512 |