Geological insights from the newly discovered granite of Sif Island between Thwaites and Pine Island glaciers
Abstract Large-scale geological structures have controlled the long-term development of the bed and thus the flow of the West Antarctic Ice Sheet (WAIS). However, complete ice cover has obscured the age and exact positions of faults and geological boundaries beneath Thwaites Glacier and Pine Island...
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Cambridge University Press (CUP)
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Online Access: | http://dx.doi.org/10.1017/s0954102023000287 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102023000287 |
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crcambridgeupr:10.1017/s0954102023000287 2024-10-13T14:01:18+00:00 Geological insights from the newly discovered granite of Sif Island between Thwaites and Pine Island glaciers Marschalek, James W. Thomson, Stuart N. Hillenbrand, Claus-Dieter Vermeesch, Pieter Siddoway, Christine Carter, Andrew Nichols, Keir Rood, Dylan H. Venturelli, Ryan A. Hammond, Samantha J. Wellner, Julia van de Flierdt, Tina Natural Environment Research Council Natural Environment Research Council Natural Environment Research Council Natural Environment Research Council Natural Environment Research Council National Science Foundation National Science Foundation 2024 http://dx.doi.org/10.1017/s0954102023000287 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102023000287 en eng Cambridge University Press (CUP) http://creativecommons.org/licenses/by/4.0/ Antarctic Science volume 36, issue 2, page 51-74 ISSN 0954-1020 1365-2079 journal-article 2024 crcambridgeupr https://doi.org/10.1017/s0954102023000287 2024-09-25T04:03:06Z Abstract Large-scale geological structures have controlled the long-term development of the bed and thus the flow of the West Antarctic Ice Sheet (WAIS). However, complete ice cover has obscured the age and exact positions of faults and geological boundaries beneath Thwaites Glacier and Pine Island Glacier, two major WAIS outlets in the Amundsen Sea sector. Here, we characterize the only rock outcrop between these two glaciers, which was exposed by the retreat of slow-flowing coastal ice in the early 2010s to form the new Sif Island. The island comprises granite, zircon U-Pb dated to ~177–174 Ma and characterized by initial ɛ Nd , 87 Sr/ 86 Sr and ɛ Hf isotope compositions of -2.3, 0.7061 and -1.3, respectively. These characteristics resemble Thurston Island/Antarctic Peninsula crustal block rocks, strongly suggesting that the Sif Island granite belongs to this province and placing the crustal block's boundary with the Marie Byrd Land province under Thwaites Glacier or its eastern shear margin. Low-temperature thermochronological data reveal that the granite underwent rapid cooling following emplacement, rapidly cooled again at ~100–90 Ma and then remained close to the Earth's surface until present. These data help date vertical displacement across the major tectonic structure beneath Pine Island Glacier to the Late Cretaceous. Article in Journal/Newspaper Amundsen Sea Antarc* Antarctic Antarctic Peninsula Antarctic Science Ice Sheet Marie Byrd Land Pine Island Glacier Sif Island Thurston Island Thwaites Glacier Cambridge University Press Amundsen Sea Antarctic Antarctic Peninsula Byrd Marie Byrd Land ENVELOPE(-130.000,-130.000,-78.000,-78.000) Pine Island Glacier ENVELOPE(-101.000,-101.000,-75.000,-75.000) Thurston ENVELOPE(-97.500,-97.500,-71.833,-71.833) Thurston Island ENVELOPE(-99.000,-99.000,-72.167,-72.167) Thwaites Glacier ENVELOPE(-106.750,-106.750,-75.500,-75.500) West Antarctic Ice Sheet Antarctic Science 1 24 |
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Open Polar |
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Cambridge University Press |
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crcambridgeupr |
language |
English |
description |
Abstract Large-scale geological structures have controlled the long-term development of the bed and thus the flow of the West Antarctic Ice Sheet (WAIS). However, complete ice cover has obscured the age and exact positions of faults and geological boundaries beneath Thwaites Glacier and Pine Island Glacier, two major WAIS outlets in the Amundsen Sea sector. Here, we characterize the only rock outcrop between these two glaciers, which was exposed by the retreat of slow-flowing coastal ice in the early 2010s to form the new Sif Island. The island comprises granite, zircon U-Pb dated to ~177–174 Ma and characterized by initial ɛ Nd , 87 Sr/ 86 Sr and ɛ Hf isotope compositions of -2.3, 0.7061 and -1.3, respectively. These characteristics resemble Thurston Island/Antarctic Peninsula crustal block rocks, strongly suggesting that the Sif Island granite belongs to this province and placing the crustal block's boundary with the Marie Byrd Land province under Thwaites Glacier or its eastern shear margin. Low-temperature thermochronological data reveal that the granite underwent rapid cooling following emplacement, rapidly cooled again at ~100–90 Ma and then remained close to the Earth's surface until present. These data help date vertical displacement across the major tectonic structure beneath Pine Island Glacier to the Late Cretaceous. |
author2 |
Natural Environment Research Council Natural Environment Research Council Natural Environment Research Council Natural Environment Research Council Natural Environment Research Council National Science Foundation National Science Foundation |
format |
Article in Journal/Newspaper |
author |
Marschalek, James W. Thomson, Stuart N. Hillenbrand, Claus-Dieter Vermeesch, Pieter Siddoway, Christine Carter, Andrew Nichols, Keir Rood, Dylan H. Venturelli, Ryan A. Hammond, Samantha J. Wellner, Julia van de Flierdt, Tina |
spellingShingle |
Marschalek, James W. Thomson, Stuart N. Hillenbrand, Claus-Dieter Vermeesch, Pieter Siddoway, Christine Carter, Andrew Nichols, Keir Rood, Dylan H. Venturelli, Ryan A. Hammond, Samantha J. Wellner, Julia van de Flierdt, Tina Geological insights from the newly discovered granite of Sif Island between Thwaites and Pine Island glaciers |
author_facet |
Marschalek, James W. Thomson, Stuart N. Hillenbrand, Claus-Dieter Vermeesch, Pieter Siddoway, Christine Carter, Andrew Nichols, Keir Rood, Dylan H. Venturelli, Ryan A. Hammond, Samantha J. Wellner, Julia van de Flierdt, Tina |
author_sort |
Marschalek, James W. |
title |
Geological insights from the newly discovered granite of Sif Island between Thwaites and Pine Island glaciers |
title_short |
Geological insights from the newly discovered granite of Sif Island between Thwaites and Pine Island glaciers |
title_full |
Geological insights from the newly discovered granite of Sif Island between Thwaites and Pine Island glaciers |
title_fullStr |
Geological insights from the newly discovered granite of Sif Island between Thwaites and Pine Island glaciers |
title_full_unstemmed |
Geological insights from the newly discovered granite of Sif Island between Thwaites and Pine Island glaciers |
title_sort |
geological insights from the newly discovered granite of sif island between thwaites and pine island glaciers |
publisher |
Cambridge University Press (CUP) |
publishDate |
2024 |
url |
http://dx.doi.org/10.1017/s0954102023000287 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102023000287 |
long_lat |
ENVELOPE(-130.000,-130.000,-78.000,-78.000) ENVELOPE(-101.000,-101.000,-75.000,-75.000) ENVELOPE(-97.500,-97.500,-71.833,-71.833) ENVELOPE(-99.000,-99.000,-72.167,-72.167) ENVELOPE(-106.750,-106.750,-75.500,-75.500) |
geographic |
Amundsen Sea Antarctic Antarctic Peninsula Byrd Marie Byrd Land Pine Island Glacier Thurston Thurston Island Thwaites Glacier West Antarctic Ice Sheet |
geographic_facet |
Amundsen Sea Antarctic Antarctic Peninsula Byrd Marie Byrd Land Pine Island Glacier Thurston Thurston Island Thwaites Glacier West Antarctic Ice Sheet |
genre |
Amundsen Sea Antarc* Antarctic Antarctic Peninsula Antarctic Science Ice Sheet Marie Byrd Land Pine Island Glacier Sif Island Thurston Island Thwaites Glacier |
genre_facet |
Amundsen Sea Antarc* Antarctic Antarctic Peninsula Antarctic Science Ice Sheet Marie Byrd Land Pine Island Glacier Sif Island Thurston Island Thwaites Glacier |
op_source |
Antarctic Science volume 36, issue 2, page 51-74 ISSN 0954-1020 1365-2079 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1017/s0954102023000287 |
container_title |
Antarctic Science |
container_start_page |
1 |
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24 |
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1812809521465131008 |