The last deglaciation of Peru and Bolivia
The tropical Andes of Peru and Bolivia are important for preserving geomorphic evidence of multiple glaciations, allowing for refinements of chronology to aid in understanding climate dynamics at a key location between hemispheres. This review focuses on the deglaciation from Late-Pleistocene maximu...
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Universidad de La Rioja
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ftdoajarticles:oai:doaj.org/article:8730a2e5e89742748fb58ede06ffdd38 2023-05-15T14:02:10+02:00 The last deglaciation of Peru and Bolivia B. Mark N. Stansell G. Zeballos 2017-09-01T00:00:00Z https://doi.org/10.18172/cig.3265 https://doaj.org/article/8730a2e5e89742748fb58ede06ffdd38 EN ES eng spa Universidad de La Rioja https://publicaciones.unirioja.es/ojs/index.php/cig/article/view/3265 https://doaj.org/toc/0211-6820 https://doaj.org/toc/1697-9540 0211-6820 1697-9540 doi:10.18172/cig.3265 https://doaj.org/article/8730a2e5e89742748fb58ede06ffdd38 Cuadernos de Investigación Geográfica, Vol 43, Iss 2, Pp 591-628 (2017) tropical andes last glacial maximum terrestrial cosmogenic nuclides paleoglaciers deglaciation Geography (General) G1-922 article 2017 ftdoajarticles https://doi.org/10.18172/cig.3265 2022-12-31T15:12:01Z The tropical Andes of Peru and Bolivia are important for preserving geomorphic evidence of multiple glaciations, allowing for refinements of chronology to aid in understanding climate dynamics at a key location between hemispheres. This review focuses on the deglaciation from Late-Pleistocene maximum positions near the global Last Glacial Maximum (LGM). We synthesize the results of the most recent published glacial geologic studies from 12 mountain ranges or regions within Peru and Bolivia where glacial moraines and drift are dated with terrestrial cosmogenic nuclides (TCN), as well as maximum and minimum limiting ages based on radiocarbon in proximal sediments. Special consideration is given to document paleoglacier valley localities with topographic information given the strong vertical mass balance sensitivity of tropical glaciers. Specific valley localities show variable and heterogeneous sequences ages and extensions of paleoglaciers, but conform to a generally cogent regional sequence revealed by more continuous lake sedimentary records. There are clear distributions of stratigraphically older and younger moraine ages that we group and discuss chronologically. The timing of the local LGM based on average TCN ages of moraine groups is 25.1 ka, but there are large uncertainties (up to 7 ka) making the relative timing with the global LGM elusive. There are a significant number of post-LGM moraines that date to 18.9 (± 0.5) ka. During the Oldest Dryas (18.0 to 14.6 ka), moraine boulders date to 16.1 (± 1.1) ka, suggesting that glaciers either experienced stillstands or readvances during this interval. The Antarctic Cold Reversal (ACR; 14.6 to 12.6 ka) is another phase of stillstanding or readvancing glaciers with moraine groups dating to 13.7 (± 0.8) ka, followed by retreating ice margins through most of the Younger Dryas (YD; 12.9 to 11.8 ka). During the early Holocene, groups of moraines in multiple valleys date to 11.0 (± 0.4) ka, marking a period when glaciers either readvanced or paused from the overall ... Article in Journal/Newspaper Antarc* Antarctic Directory of Open Access Journals: DOAJ Articles Antarctic The Antarctic Cuadernos de Investigación Geográfica 43 2 591 |
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English Spanish |
topic |
tropical andes last glacial maximum terrestrial cosmogenic nuclides paleoglaciers deglaciation Geography (General) G1-922 |
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tropical andes last glacial maximum terrestrial cosmogenic nuclides paleoglaciers deglaciation Geography (General) G1-922 B. Mark N. Stansell G. Zeballos The last deglaciation of Peru and Bolivia |
topic_facet |
tropical andes last glacial maximum terrestrial cosmogenic nuclides paleoglaciers deglaciation Geography (General) G1-922 |
description |
The tropical Andes of Peru and Bolivia are important for preserving geomorphic evidence of multiple glaciations, allowing for refinements of chronology to aid in understanding climate dynamics at a key location between hemispheres. This review focuses on the deglaciation from Late-Pleistocene maximum positions near the global Last Glacial Maximum (LGM). We synthesize the results of the most recent published glacial geologic studies from 12 mountain ranges or regions within Peru and Bolivia where glacial moraines and drift are dated with terrestrial cosmogenic nuclides (TCN), as well as maximum and minimum limiting ages based on radiocarbon in proximal sediments. Special consideration is given to document paleoglacier valley localities with topographic information given the strong vertical mass balance sensitivity of tropical glaciers. Specific valley localities show variable and heterogeneous sequences ages and extensions of paleoglaciers, but conform to a generally cogent regional sequence revealed by more continuous lake sedimentary records. There are clear distributions of stratigraphically older and younger moraine ages that we group and discuss chronologically. The timing of the local LGM based on average TCN ages of moraine groups is 25.1 ka, but there are large uncertainties (up to 7 ka) making the relative timing with the global LGM elusive. There are a significant number of post-LGM moraines that date to 18.9 (± 0.5) ka. During the Oldest Dryas (18.0 to 14.6 ka), moraine boulders date to 16.1 (± 1.1) ka, suggesting that glaciers either experienced stillstands or readvances during this interval. The Antarctic Cold Reversal (ACR; 14.6 to 12.6 ka) is another phase of stillstanding or readvancing glaciers with moraine groups dating to 13.7 (± 0.8) ka, followed by retreating ice margins through most of the Younger Dryas (YD; 12.9 to 11.8 ka). During the early Holocene, groups of moraines in multiple valleys date to 11.0 (± 0.4) ka, marking a period when glaciers either readvanced or paused from the overall ... |
format |
Article in Journal/Newspaper |
author |
B. Mark N. Stansell G. Zeballos |
author_facet |
B. Mark N. Stansell G. Zeballos |
author_sort |
B. Mark |
title |
The last deglaciation of Peru and Bolivia |
title_short |
The last deglaciation of Peru and Bolivia |
title_full |
The last deglaciation of Peru and Bolivia |
title_fullStr |
The last deglaciation of Peru and Bolivia |
title_full_unstemmed |
The last deglaciation of Peru and Bolivia |
title_sort |
last deglaciation of peru and bolivia |
publisher |
Universidad de La Rioja |
publishDate |
2017 |
url |
https://doi.org/10.18172/cig.3265 https://doaj.org/article/8730a2e5e89742748fb58ede06ffdd38 |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
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Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
Cuadernos de Investigación Geográfica, Vol 43, Iss 2, Pp 591-628 (2017) |
op_relation |
https://publicaciones.unirioja.es/ojs/index.php/cig/article/view/3265 https://doaj.org/toc/0211-6820 https://doaj.org/toc/1697-9540 0211-6820 1697-9540 doi:10.18172/cig.3265 https://doaj.org/article/8730a2e5e89742748fb58ede06ffdd38 |
op_doi |
https://doi.org/10.18172/cig.3265 |
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Cuadernos de Investigación Geográfica |
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43 |
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2 |
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