Northeastern Patagonian Glacier Advances (43°S) Reflect Northward Migration of the Southern Westerlies Towards the End of the Last Glaciation
The last glacial termination was a key event during Earth’s Quaternary history that was associated with rapid, high-magnitude environmental and climatic change. Identifying its trigger mechanisms is critical for understanding Earth’s modern climate system over millennial timescales. It has been prop...
Published in: | Frontiers in Earth Science |
---|---|
Main Authors: | , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Frontiers Media S.A.
2021
|
Subjects: | |
Online Access: | https://doi.org/10.3389/feart.2021.751987 https://doaj.org/article/3c4104214cfe4bdeaffaccb95d63ca0a |
id |
ftdoajarticles:oai:doaj.org/article:3c4104214cfe4bdeaffaccb95d63ca0a |
---|---|
record_format |
openpolar |
spelling |
ftdoajarticles:oai:doaj.org/article:3c4104214cfe4bdeaffaccb95d63ca0a 2023-05-15T16:41:27+02:00 Northeastern Patagonian Glacier Advances (43°S) Reflect Northward Migration of the Southern Westerlies Towards the End of the Last Glaciation Tancrède P. M. Leger Andrew S. Hein Daniel Goldberg Irene Schimmelpfennig Maximillian S. Van Wyk de Vries Robert G. Bingham ASTER Team Georges Aumaitre 2021-11-01T00:00:00Z https://doi.org/10.3389/feart.2021.751987 https://doaj.org/article/3c4104214cfe4bdeaffaccb95d63ca0a EN eng Frontiers Media S.A. https://www.frontiersin.org/articles/10.3389/feart.2021.751987/full https://doaj.org/toc/2296-6463 2296-6463 doi:10.3389/feart.2021.751987 https://doaj.org/article/3c4104214cfe4bdeaffaccb95d63ca0a Frontiers in Earth Science, Vol 9 (2021) Patagonia glaciers and climate last glacial termination cosmogenic nuclide surface exposure dating glacier modelling southern westerly winds Science Q article 2021 ftdoajarticles https://doi.org/10.3389/feart.2021.751987 2022-12-31T09:16:11Z The last glacial termination was a key event during Earth’s Quaternary history that was associated with rapid, high-magnitude environmental and climatic change. Identifying its trigger mechanisms is critical for understanding Earth’s modern climate system over millennial timescales. It has been proposed that latitudinal shifts of the Southern Hemisphere Westerly Wind belt and the coupled Subtropical Front are important components of the changes leading to global deglaciation, making them essential to investigate and reconstruct empirically. The Patagonian Andes are part of the only continental landmass that fully intersects the Southern Westerly Winds, and thus present an opportunity to study their former latitudinal migrations through time and to constrain southern mid-latitude palaeo-climates. Here we use a combination of geomorphological mapping, terrestrial cosmogenic nuclide exposure dating and glacial numerical modelling to reconstruct the late-Last Glacial Maximum (LGM) behaviour and surface mass balance of two mountain glaciers of northeastern Patagonia (43°S, 71°W), the El Loro and Río Comisario palaeo-glaciers. In both valleys, we find geomorphological evidence of glacier advances that occurred after the retreat of the main ice-sheet outlet glacier from its LGM margins. We date the outermost moraine in the El Loro valley to 18.0 ± 1.15 ka. Moreover, a series of moraine-matching simulations were run for both glaciers using a spatially-distributed ice-flow model coupled with a positive degree-day surface mass balance parameterisation. Following a correction for cumulative local surface uplift resulting from glacial isostatic adjustment since ∼18 ka, which we estimate to be ∼130 m, the glacier model suggests that regional mean annual temperatures were between 1.9 and 2.8°C lower than present at around 18.0 ± 1.15 ka, while precipitation was between ∼50 and ∼380% higher than today. Our findings support the proposed equatorward migration of the precipitation-bearing Southern Westerly Wind belt towards the ... Article in Journal/Newspaper Ice Sheet Directory of Open Access Journals: DOAJ Articles Patagonia Frontiers in Earth Science 9 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Patagonia glaciers and climate last glacial termination cosmogenic nuclide surface exposure dating glacier modelling southern westerly winds Science Q |
spellingShingle |
Patagonia glaciers and climate last glacial termination cosmogenic nuclide surface exposure dating glacier modelling southern westerly winds Science Q Tancrède P. M. Leger Andrew S. Hein Daniel Goldberg Irene Schimmelpfennig Maximillian S. Van Wyk de Vries Robert G. Bingham ASTER Team Georges Aumaitre Northeastern Patagonian Glacier Advances (43°S) Reflect Northward Migration of the Southern Westerlies Towards the End of the Last Glaciation |
topic_facet |
Patagonia glaciers and climate last glacial termination cosmogenic nuclide surface exposure dating glacier modelling southern westerly winds Science Q |
description |
The last glacial termination was a key event during Earth’s Quaternary history that was associated with rapid, high-magnitude environmental and climatic change. Identifying its trigger mechanisms is critical for understanding Earth’s modern climate system over millennial timescales. It has been proposed that latitudinal shifts of the Southern Hemisphere Westerly Wind belt and the coupled Subtropical Front are important components of the changes leading to global deglaciation, making them essential to investigate and reconstruct empirically. The Patagonian Andes are part of the only continental landmass that fully intersects the Southern Westerly Winds, and thus present an opportunity to study their former latitudinal migrations through time and to constrain southern mid-latitude palaeo-climates. Here we use a combination of geomorphological mapping, terrestrial cosmogenic nuclide exposure dating and glacial numerical modelling to reconstruct the late-Last Glacial Maximum (LGM) behaviour and surface mass balance of two mountain glaciers of northeastern Patagonia (43°S, 71°W), the El Loro and Río Comisario palaeo-glaciers. In both valleys, we find geomorphological evidence of glacier advances that occurred after the retreat of the main ice-sheet outlet glacier from its LGM margins. We date the outermost moraine in the El Loro valley to 18.0 ± 1.15 ka. Moreover, a series of moraine-matching simulations were run for both glaciers using a spatially-distributed ice-flow model coupled with a positive degree-day surface mass balance parameterisation. Following a correction for cumulative local surface uplift resulting from glacial isostatic adjustment since ∼18 ka, which we estimate to be ∼130 m, the glacier model suggests that regional mean annual temperatures were between 1.9 and 2.8°C lower than present at around 18.0 ± 1.15 ka, while precipitation was between ∼50 and ∼380% higher than today. Our findings support the proposed equatorward migration of the precipitation-bearing Southern Westerly Wind belt towards the ... |
format |
Article in Journal/Newspaper |
author |
Tancrède P. M. Leger Andrew S. Hein Daniel Goldberg Irene Schimmelpfennig Maximillian S. Van Wyk de Vries Robert G. Bingham ASTER Team Georges Aumaitre |
author_facet |
Tancrède P. M. Leger Andrew S. Hein Daniel Goldberg Irene Schimmelpfennig Maximillian S. Van Wyk de Vries Robert G. Bingham ASTER Team Georges Aumaitre |
author_sort |
Tancrède P. M. Leger |
title |
Northeastern Patagonian Glacier Advances (43°S) Reflect Northward Migration of the Southern Westerlies Towards the End of the Last Glaciation |
title_short |
Northeastern Patagonian Glacier Advances (43°S) Reflect Northward Migration of the Southern Westerlies Towards the End of the Last Glaciation |
title_full |
Northeastern Patagonian Glacier Advances (43°S) Reflect Northward Migration of the Southern Westerlies Towards the End of the Last Glaciation |
title_fullStr |
Northeastern Patagonian Glacier Advances (43°S) Reflect Northward Migration of the Southern Westerlies Towards the End of the Last Glaciation |
title_full_unstemmed |
Northeastern Patagonian Glacier Advances (43°S) Reflect Northward Migration of the Southern Westerlies Towards the End of the Last Glaciation |
title_sort |
northeastern patagonian glacier advances (43°s) reflect northward migration of the southern westerlies towards the end of the last glaciation |
publisher |
Frontiers Media S.A. |
publishDate |
2021 |
url |
https://doi.org/10.3389/feart.2021.751987 https://doaj.org/article/3c4104214cfe4bdeaffaccb95d63ca0a |
geographic |
Patagonia |
geographic_facet |
Patagonia |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_source |
Frontiers in Earth Science, Vol 9 (2021) |
op_relation |
https://www.frontiersin.org/articles/10.3389/feart.2021.751987/full https://doaj.org/toc/2296-6463 2296-6463 doi:10.3389/feart.2021.751987 https://doaj.org/article/3c4104214cfe4bdeaffaccb95d63ca0a |
op_doi |
https://doi.org/10.3389/feart.2021.751987 |
container_title |
Frontiers in Earth Science |
container_volume |
9 |
_version_ |
1766031881833283584 |