Exposure dating of Late Glacial and pre-LGM moraines in the Cordon de Doña Rosa, Northern/Central Chile (~31° S)
Despite the important role of the Central Andes (15–30° S) for climate reconstruction, knowledge about the Quaternary glaciation is very limited due to the scarcity of organic material for radiocarbon dating. We applied 10Be surface exposure dating (SED) on 22 boulders from moraines in the Cordon de...
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ftethz:oai:www.research-collection.ethz.ch:20.500.11850/554198 2023-05-15T13:41:37+02:00 Exposure dating of Late Glacial and pre-LGM moraines in the Cordon de Doña Rosa, Northern/Central Chile (~31° S) Zech, Roland Kull, Christoph Kubik, Peter W. Veit, Heinz 2007-01-15 application/application/pdf https://hdl.handle.net/20.500.11850/554198 https://doi.org/10.3929/ethz-b-000554198 en eng Copernicus info:eu-repo/semantics/altIdentifier/doi/10.5194/cp-3-1-2007 http://hdl.handle.net/20.500.11850/554198 doi:10.3929/ethz-b-000554198 info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by-nc-sa/2.5/ Creative Commons Attribution-NonCommercial-ShareAlike 2.5 Generic CC-BY-NC-SA Climate of the Past, 3 (1) info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 2007 ftethz https://doi.org/20.500.11850/554198 https://doi.org/10.3929/ethz-b-000554198 https://doi.org/10.5194/cp-3-1-2007 2023-02-13T01:05:03Z Despite the important role of the Central Andes (15–30° S) for climate reconstruction, knowledge about the Quaternary glaciation is very limited due to the scarcity of organic material for radiocarbon dating. We applied 10Be surface exposure dating (SED) on 22 boulders from moraines in the Cordon de Doña Rosa, Northern/Central Chile (~31° S). The results show that several glacial advances in the southern Central Andes occurred during the Late Glacial between ~14.7±1.5 and 11.6±1.2 ka. A much more extensive glaciation is dated to ~32±3 ka, predating the temperature minimum of the global LGM (Last Glacial Maximum: ~20 ka). Reviewing these results in the paleoclimatic context, we conclude that the Late Glacial advances were most likely caused by an intensification of the tropical circulation and a corresponding increase in summer precipitation. High-latitude temperatures minima, e.g. the Younger Dryas (YD) and the Antarctic Cold Reversal (ACR) may have triggered individual advances, but current systematic exposure age uncertainties limit precise correlations. The absence of LGM moraines indicates that moisture advection was too limited to allow significant glacial advances at ~20 ka. The tropical circulation was less intensive despite the maximum in austral summer insolation. Winter precipitation was apparently also insufficient, although pollen and marine studies indicate a northward shift of the westerlies at that time. The dominant pre-LGM glacial advances in Northern/Central Chile at ~32 ka required lower temperatures and increased precipitation than today. We conclude that the westerlies were more intense and/or shifted equatorward, possibly due to increased snow and ice cover at higher southern latitudes coinciding with a minimum of insolation. ISSN:1814-9324 ISSN:1814-9332 Article in Journal/Newspaper Antarc* Antarctic ETH Zürich Research Collection Antarctic The Antarctic Austral |
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Open Polar |
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ETH Zürich Research Collection |
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ftethz |
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English |
description |
Despite the important role of the Central Andes (15–30° S) for climate reconstruction, knowledge about the Quaternary glaciation is very limited due to the scarcity of organic material for radiocarbon dating. We applied 10Be surface exposure dating (SED) on 22 boulders from moraines in the Cordon de Doña Rosa, Northern/Central Chile (~31° S). The results show that several glacial advances in the southern Central Andes occurred during the Late Glacial between ~14.7±1.5 and 11.6±1.2 ka. A much more extensive glaciation is dated to ~32±3 ka, predating the temperature minimum of the global LGM (Last Glacial Maximum: ~20 ka). Reviewing these results in the paleoclimatic context, we conclude that the Late Glacial advances were most likely caused by an intensification of the tropical circulation and a corresponding increase in summer precipitation. High-latitude temperatures minima, e.g. the Younger Dryas (YD) and the Antarctic Cold Reversal (ACR) may have triggered individual advances, but current systematic exposure age uncertainties limit precise correlations. The absence of LGM moraines indicates that moisture advection was too limited to allow significant glacial advances at ~20 ka. The tropical circulation was less intensive despite the maximum in austral summer insolation. Winter precipitation was apparently also insufficient, although pollen and marine studies indicate a northward shift of the westerlies at that time. The dominant pre-LGM glacial advances in Northern/Central Chile at ~32 ka required lower temperatures and increased precipitation than today. We conclude that the westerlies were more intense and/or shifted equatorward, possibly due to increased snow and ice cover at higher southern latitudes coinciding with a minimum of insolation. ISSN:1814-9324 ISSN:1814-9332 |
format |
Article in Journal/Newspaper |
author |
Zech, Roland Kull, Christoph Kubik, Peter W. Veit, Heinz |
spellingShingle |
Zech, Roland Kull, Christoph Kubik, Peter W. Veit, Heinz Exposure dating of Late Glacial and pre-LGM moraines in the Cordon de Doña Rosa, Northern/Central Chile (~31° S) |
author_facet |
Zech, Roland Kull, Christoph Kubik, Peter W. Veit, Heinz |
author_sort |
Zech, Roland |
title |
Exposure dating of Late Glacial and pre-LGM moraines in the Cordon de Doña Rosa, Northern/Central Chile (~31° S) |
title_short |
Exposure dating of Late Glacial and pre-LGM moraines in the Cordon de Doña Rosa, Northern/Central Chile (~31° S) |
title_full |
Exposure dating of Late Glacial and pre-LGM moraines in the Cordon de Doña Rosa, Northern/Central Chile (~31° S) |
title_fullStr |
Exposure dating of Late Glacial and pre-LGM moraines in the Cordon de Doña Rosa, Northern/Central Chile (~31° S) |
title_full_unstemmed |
Exposure dating of Late Glacial and pre-LGM moraines in the Cordon de Doña Rosa, Northern/Central Chile (~31° S) |
title_sort |
exposure dating of late glacial and pre-lgm moraines in the cordon de doña rosa, northern/central chile (~31° s) |
publisher |
Copernicus |
publishDate |
2007 |
url |
https://hdl.handle.net/20.500.11850/554198 https://doi.org/10.3929/ethz-b-000554198 |
geographic |
Antarctic The Antarctic Austral |
geographic_facet |
Antarctic The Antarctic Austral |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
Climate of the Past, 3 (1) |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.5194/cp-3-1-2007 http://hdl.handle.net/20.500.11850/554198 doi:10.3929/ethz-b-000554198 |
op_rights |
info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by-nc-sa/2.5/ Creative Commons Attribution-NonCommercial-ShareAlike 2.5 Generic |
op_rightsnorm |
CC-BY-NC-SA |
op_doi |
https://doi.org/20.500.11850/554198 https://doi.org/10.3929/ethz-b-000554198 https://doi.org/10.5194/cp-3-1-2007 |
_version_ |
1766153043704807424 |