Quartz grain microtextures illuminate Pliocene periglacial sand fluxes on the Antarctic continental margin
Abstract On high‐latitude continental margins sediment is supplied from land to the deep sea through a variety of processes, including iceberg and sea‐ice rafting, and bottom current transport. The accurate reconstruction of sediment fluxes from these sources through time is important in palaeoclima...
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ftdoajarticles:oai:doaj.org/article:9942766e0495426c82253dde75b90d86 2023-05-15T13:41:06+02:00 Quartz grain microtextures illuminate Pliocene periglacial sand fluxes on the Antarctic continental margin Sandra Passchier Melissa A. Hansen Jessica Rosenberg 2021-09-01T00:00:00Z https://doi.org/10.1002/dep2.157 https://doaj.org/article/9942766e0495426c82253dde75b90d86 EN eng Wiley https://doi.org/10.1002/dep2.157 https://doaj.org/toc/2055-4877 2055-4877 doi:10.1002/dep2.157 https://doaj.org/article/9942766e0495426c82253dde75b90d86 The Depositional Record, Vol 7, Iss 3, Pp 564-581 (2021) Antarctica eolian IRD microtexture Geology QE1-996.5 article 2021 ftdoajarticles https://doi.org/10.1002/dep2.157 2022-12-31T13:18:55Z Abstract On high‐latitude continental margins sediment is supplied from land to the deep sea through a variety of processes, including iceberg and sea‐ice rafting, and bottom current transport. The accurate reconstruction of sediment fluxes from these sources through time is important in palaeoclimate reconstructions. The goal of this study was to assess a shift in the intensity of glacial processes, iceberg and sea‐ice rafting during the Pliocene through an investigation of coarse sediment deposited at the AND‐2A site in the Ross Sea and at International Ocean Discovery Program Site U1359 on the Antarctic continental rise. Terrigenous particle‐size distributions and suites of quartz grain microtextures in the sand fraction of the deep‐sea sediments were compared to those from Antarctic glaciomarine diamictites as a baseline for proximal glacial sediment in its source area. Using images acquired through Scanning Electron Microscopy, and following a quantitative approach, fewer immature and potentially glacially transported grains were found in Pliocene deep‐sea sand fractions than in ice‐contact sediments. Specifically, in the lower Pliocene interval silt and fine sand percentages are elevated, and microtextures in at least half of the sand fraction are inconsistent with a primary glacial origin. Larger numbers of chemically altered and abraded grains in the deep‐sea sand fraction, along with microtextures that are diagnostic of periglacial environments, suggest a role for eolian sediment transport. These results highlight the anomalous nature of high‐latitude sediment fluxes during prolonged periods of ice retreat. Furthermore, the identification of a significant offshore sediment flux during Antarctic deglaciation has implications for estimated nutrient supply to the Southern Ocean and the potential for high‐latitude climate feedbacks under warmer climate states. Article in Journal/Newspaper Antarc* Antarctic Antarctica Iceberg* Ross Sea Sea ice Southern Ocean Directory of Open Access Journals: DOAJ Articles Antarctic Southern Ocean The Antarctic Ross Sea The Depositional Record 7 3 564 581 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Antarctica eolian IRD microtexture Geology QE1-996.5 |
spellingShingle |
Antarctica eolian IRD microtexture Geology QE1-996.5 Sandra Passchier Melissa A. Hansen Jessica Rosenberg Quartz grain microtextures illuminate Pliocene periglacial sand fluxes on the Antarctic continental margin |
topic_facet |
Antarctica eolian IRD microtexture Geology QE1-996.5 |
description |
Abstract On high‐latitude continental margins sediment is supplied from land to the deep sea through a variety of processes, including iceberg and sea‐ice rafting, and bottom current transport. The accurate reconstruction of sediment fluxes from these sources through time is important in palaeoclimate reconstructions. The goal of this study was to assess a shift in the intensity of glacial processes, iceberg and sea‐ice rafting during the Pliocene through an investigation of coarse sediment deposited at the AND‐2A site in the Ross Sea and at International Ocean Discovery Program Site U1359 on the Antarctic continental rise. Terrigenous particle‐size distributions and suites of quartz grain microtextures in the sand fraction of the deep‐sea sediments were compared to those from Antarctic glaciomarine diamictites as a baseline for proximal glacial sediment in its source area. Using images acquired through Scanning Electron Microscopy, and following a quantitative approach, fewer immature and potentially glacially transported grains were found in Pliocene deep‐sea sand fractions than in ice‐contact sediments. Specifically, in the lower Pliocene interval silt and fine sand percentages are elevated, and microtextures in at least half of the sand fraction are inconsistent with a primary glacial origin. Larger numbers of chemically altered and abraded grains in the deep‐sea sand fraction, along with microtextures that are diagnostic of periglacial environments, suggest a role for eolian sediment transport. These results highlight the anomalous nature of high‐latitude sediment fluxes during prolonged periods of ice retreat. Furthermore, the identification of a significant offshore sediment flux during Antarctic deglaciation has implications for estimated nutrient supply to the Southern Ocean and the potential for high‐latitude climate feedbacks under warmer climate states. |
format |
Article in Journal/Newspaper |
author |
Sandra Passchier Melissa A. Hansen Jessica Rosenberg |
author_facet |
Sandra Passchier Melissa A. Hansen Jessica Rosenberg |
author_sort |
Sandra Passchier |
title |
Quartz grain microtextures illuminate Pliocene periglacial sand fluxes on the Antarctic continental margin |
title_short |
Quartz grain microtextures illuminate Pliocene periglacial sand fluxes on the Antarctic continental margin |
title_full |
Quartz grain microtextures illuminate Pliocene periglacial sand fluxes on the Antarctic continental margin |
title_fullStr |
Quartz grain microtextures illuminate Pliocene periglacial sand fluxes on the Antarctic continental margin |
title_full_unstemmed |
Quartz grain microtextures illuminate Pliocene periglacial sand fluxes on the Antarctic continental margin |
title_sort |
quartz grain microtextures illuminate pliocene periglacial sand fluxes on the antarctic continental margin |
publisher |
Wiley |
publishDate |
2021 |
url |
https://doi.org/10.1002/dep2.157 https://doaj.org/article/9942766e0495426c82253dde75b90d86 |
geographic |
Antarctic Southern Ocean The Antarctic Ross Sea |
geographic_facet |
Antarctic Southern Ocean The Antarctic Ross Sea |
genre |
Antarc* Antarctic Antarctica Iceberg* Ross Sea Sea ice Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctica Iceberg* Ross Sea Sea ice Southern Ocean |
op_source |
The Depositional Record, Vol 7, Iss 3, Pp 564-581 (2021) |
op_relation |
https://doi.org/10.1002/dep2.157 https://doaj.org/toc/2055-4877 2055-4877 doi:10.1002/dep2.157 https://doaj.org/article/9942766e0495426c82253dde75b90d86 |
op_doi |
https://doi.org/10.1002/dep2.157 |
container_title |
The Depositional Record |
container_volume |
7 |
container_issue |
3 |
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564 |
op_container_end_page |
581 |
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