Exposure dating of Late Glacial and pre-LGM moraines in the Cordon de Doña Rosa, Northern/Central Chile (?31° S)
International audience 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 10 Be surface exposure dating (SED) on 22 boulders from m...
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ftccsdartic:oai:HAL:hal-00298151v1 2024-02-04T09:55:25+01:00 Exposure dating of Late Glacial and pre-LGM moraines in the Cordon de Doña Rosa, Northern/Central Chile (?31° S) Zech, R. Kull, C. Kubik, P. W. Veit, H. Institute of Geography Bern Universität Bern / University of Bern (UNIBE) PAGES International Project Office Paul Scherrer Institute c/o Institute of Particle Physics 2006-09-25 https://hal.science/hal-00298151 https://hal.science/hal-00298151/document https://hal.science/hal-00298151/file/cpd-2-847-2006.pdf en eng HAL CCSD European Geosciences Union (EGU) hal-00298151 https://hal.science/hal-00298151 https://hal.science/hal-00298151/document https://hal.science/hal-00298151/file/cpd-2-847-2006.pdf info:eu-repo/semantics/OpenAccess ISSN: 1814-9340 EISSN: 1814-9359 Climate of the Past Discussions https://hal.science/hal-00298151 Climate of the Past Discussions, 2006, 2 (5), pp.847-878 [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment [SDU.STU]Sciences of the Universe [physics]/Earth Sciences info:eu-repo/semantics/article Journal articles 2006 ftccsdartic 2024-01-06T23:35:38Z International audience 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 10 Be 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 BP. A much more extensive glaciation is dated to ~32±3 ka BP, predating the temperature minimum of the global LGM (Last Glacial Maximum: ~20 ka BP). Reviewing these results in the paleoclimatic context, we note that the Late Glacial advances coincide with (i) lower temperatures during the Younger Dryas (YD) and the Antarctic Cold Reversal (ACR), (ii) the intensification of the tropical circulation and a corresponding increase in summer precipitation and (iii) a minimum in austral summer insolation favouring reduced ablation. The absence of LGM moraines indicates that moisture advection was too limited to allow significant glacial advances at ~20 ka BP. The tropical circulation was much 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 BP required lower temperatures and increased precipitation than today. They coincide with (i) a minimum of southern high-latitude insolation suggesting an equatorward shift of the westerlies due to increased snow and ice cover, (ii) a maximum winter insolation resulting in ocean-continental temperature and pressure gradients favouring moisture advection, (iii) minimum summer insolation suggesting lower temperatures and reduced ablation and (iv) low high-latitude temperatures corroborating that they affect subtropical and tropical temperatures. ... Article in Journal/Newspaper Antarc* Antarctic Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Antarctic Austral The Antarctic |
institution |
Open Polar |
collection |
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
op_collection_id |
ftccsdartic |
language |
English |
topic |
[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
spellingShingle |
[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment [SDU.STU]Sciences of the Universe [physics]/Earth Sciences Zech, R. Kull, C. Kubik, P. W. Veit, H. Exposure dating of Late Glacial and pre-LGM moraines in the Cordon de Doña Rosa, Northern/Central Chile (?31° S) |
topic_facet |
[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
International audience 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 10 Be 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 BP. A much more extensive glaciation is dated to ~32±3 ka BP, predating the temperature minimum of the global LGM (Last Glacial Maximum: ~20 ka BP). Reviewing these results in the paleoclimatic context, we note that the Late Glacial advances coincide with (i) lower temperatures during the Younger Dryas (YD) and the Antarctic Cold Reversal (ACR), (ii) the intensification of the tropical circulation and a corresponding increase in summer precipitation and (iii) a minimum in austral summer insolation favouring reduced ablation. The absence of LGM moraines indicates that moisture advection was too limited to allow significant glacial advances at ~20 ka BP. The tropical circulation was much 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 BP required lower temperatures and increased precipitation than today. They coincide with (i) a minimum of southern high-latitude insolation suggesting an equatorward shift of the westerlies due to increased snow and ice cover, (ii) a maximum winter insolation resulting in ocean-continental temperature and pressure gradients favouring moisture advection, (iii) minimum summer insolation suggesting lower temperatures and reduced ablation and (iv) low high-latitude temperatures corroborating that they affect subtropical and tropical temperatures. ... |
author2 |
Institute of Geography Bern Universität Bern / University of Bern (UNIBE) PAGES International Project Office Paul Scherrer Institute c/o Institute of Particle Physics |
format |
Article in Journal/Newspaper |
author |
Zech, R. Kull, C. Kubik, P. W. Veit, H. |
author_facet |
Zech, R. Kull, C. Kubik, P. W. Veit, H. |
author_sort |
Zech, R. |
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 |
HAL CCSD |
publishDate |
2006 |
url |
https://hal.science/hal-00298151 https://hal.science/hal-00298151/document https://hal.science/hal-00298151/file/cpd-2-847-2006.pdf |
geographic |
Antarctic Austral The Antarctic |
geographic_facet |
Antarctic Austral The Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
ISSN: 1814-9340 EISSN: 1814-9359 Climate of the Past Discussions https://hal.science/hal-00298151 Climate of the Past Discussions, 2006, 2 (5), pp.847-878 |
op_relation |
hal-00298151 https://hal.science/hal-00298151 https://hal.science/hal-00298151/document https://hal.science/hal-00298151/file/cpd-2-847-2006.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1789959399708557312 |