Palynological signal of the Younger Dryas in the tropical Venezuelan Andes
The occurrence, or not, of the Younger Dryas cold reversal in the tropical Andes remains a controversial topic. This study reports a clear signal for this event in the Venezuelan Andes, employing high-resolution palynological analysis of a well-dated sediment core from Laguna de Los Anteojos, situat...
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ftopenunivgb:oai:oro.open.ac.uk:35713 2023-06-11T04:12:22+02:00 Palynological signal of the Younger Dryas in the tropical Venezuelan Andes Rull, Valentí Stansell, Nathan D. Montoya, Encarni Bezada, Maximiliano Abbott, Mark B. 2010 https://oro.open.ac.uk/35713/ https://doi.org/10.1016/j.quascirev.2010.07.012 unknown Rull, Valentí; Stansell, Nathan D.; Montoya, Encarni <http://oro.open.ac.uk/view/person/em8243.html>; Bezada, Maximiliano and Abbott, Mark B. (2010). Palynological signal of the Younger Dryas in the tropical Venezuelan Andes. Quaternary Science Reviews, 29(23-24) pp. 3045–3056. Journal Item None PeerReviewed 2010 ftopenunivgb https://doi.org/10.1016/j.quascirev.2010.07.012 2023-05-28T05:49:24Z The occurrence, or not, of the Younger Dryas cold reversal in the tropical Andes remains a controversial topic. This study reports a clear signal for this event in the Venezuelan Andes, employing high-resolution palynological analysis of a well-dated sediment core from Laguna de Los Anteojos, situated around 3900 m elevation, within grass páramo vegetation. The lake is surrounded by some Polylepis forests which are close to their upper distribution limit. The section of the core discussed here is 150-cm long and dated between about 14.68 and 9.35 cal kyr BP, using a polynomial age-depth model based on six AMS radiocarbon dates. Between 12.86 and 11.65 cal kyr BP, an abrupt shift occurred in the pollen assemblage, manifested by a decline of Podocarpus, Polylepis and Huperzia, combined with an increase in Poaceae and Asteraceae. The aquatic pteridophyte Isoëtes also decreased and disappeard, and the algae remains show their minimum values. Pollen assemblages from the Younger Dryas interval show maximum dissimilarity values compared with today’s pollen assemblage, and are more similar to modern analogs from superpáramo vegetation, growing at elevations 400–500 m higher. A lowering of vegetation zones of this magnitude corresponds to a temperature decline of between 2.5 and 3.8 °C. During this colder interval lake levels may have been lower, suggesting a decrease in available moisture. The vegetation shift documented in Anteojos record between 12.86 and 11.65 cal kyr BP is comparable to the El Abra Stadial in the Colombian Andes but it differs in magnitude. The Anteojos shift is better dated and coincides with the Younger Dryas chron as recorded in the Cariaco Basin sea surface temperature reconstructions and records of continental runoff, as well as in the oxygen isotope measurements from the Greenland ice cores. When compared to other proxies of quasi-immediate response to climate, the time lag for the response of vegetation to climate is found to be negligible at a centennial scale. The Polylepis pollen curve is ... Article in Journal/Newspaper Greenland Greenland ice cores The Open University: Open Research Online (ORO) Greenland Quaternary Science Reviews 29 23-24 3045 3056 |
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Open Polar |
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The Open University: Open Research Online (ORO) |
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ftopenunivgb |
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unknown |
description |
The occurrence, or not, of the Younger Dryas cold reversal in the tropical Andes remains a controversial topic. This study reports a clear signal for this event in the Venezuelan Andes, employing high-resolution palynological analysis of a well-dated sediment core from Laguna de Los Anteojos, situated around 3900 m elevation, within grass páramo vegetation. The lake is surrounded by some Polylepis forests which are close to their upper distribution limit. The section of the core discussed here is 150-cm long and dated between about 14.68 and 9.35 cal kyr BP, using a polynomial age-depth model based on six AMS radiocarbon dates. Between 12.86 and 11.65 cal kyr BP, an abrupt shift occurred in the pollen assemblage, manifested by a decline of Podocarpus, Polylepis and Huperzia, combined with an increase in Poaceae and Asteraceae. The aquatic pteridophyte Isoëtes also decreased and disappeard, and the algae remains show their minimum values. Pollen assemblages from the Younger Dryas interval show maximum dissimilarity values compared with today’s pollen assemblage, and are more similar to modern analogs from superpáramo vegetation, growing at elevations 400–500 m higher. A lowering of vegetation zones of this magnitude corresponds to a temperature decline of between 2.5 and 3.8 °C. During this colder interval lake levels may have been lower, suggesting a decrease in available moisture. The vegetation shift documented in Anteojos record between 12.86 and 11.65 cal kyr BP is comparable to the El Abra Stadial in the Colombian Andes but it differs in magnitude. The Anteojos shift is better dated and coincides with the Younger Dryas chron as recorded in the Cariaco Basin sea surface temperature reconstructions and records of continental runoff, as well as in the oxygen isotope measurements from the Greenland ice cores. When compared to other proxies of quasi-immediate response to climate, the time lag for the response of vegetation to climate is found to be negligible at a centennial scale. The Polylepis pollen curve is ... |
format |
Article in Journal/Newspaper |
author |
Rull, Valentí Stansell, Nathan D. Montoya, Encarni Bezada, Maximiliano Abbott, Mark B. |
spellingShingle |
Rull, Valentí Stansell, Nathan D. Montoya, Encarni Bezada, Maximiliano Abbott, Mark B. Palynological signal of the Younger Dryas in the tropical Venezuelan Andes |
author_facet |
Rull, Valentí Stansell, Nathan D. Montoya, Encarni Bezada, Maximiliano Abbott, Mark B. |
author_sort |
Rull, Valentí |
title |
Palynological signal of the Younger Dryas in the tropical Venezuelan Andes |
title_short |
Palynological signal of the Younger Dryas in the tropical Venezuelan Andes |
title_full |
Palynological signal of the Younger Dryas in the tropical Venezuelan Andes |
title_fullStr |
Palynological signal of the Younger Dryas in the tropical Venezuelan Andes |
title_full_unstemmed |
Palynological signal of the Younger Dryas in the tropical Venezuelan Andes |
title_sort |
palynological signal of the younger dryas in the tropical venezuelan andes |
publishDate |
2010 |
url |
https://oro.open.ac.uk/35713/ https://doi.org/10.1016/j.quascirev.2010.07.012 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Greenland ice cores |
genre_facet |
Greenland Greenland ice cores |
op_relation |
Rull, Valentí; Stansell, Nathan D.; Montoya, Encarni <http://oro.open.ac.uk/view/person/em8243.html>; Bezada, Maximiliano and Abbott, Mark B. (2010). Palynological signal of the Younger Dryas in the tropical Venezuelan Andes. Quaternary Science Reviews, 29(23-24) pp. 3045–3056. |
op_doi |
https://doi.org/10.1016/j.quascirev.2010.07.012 |
container_title |
Quaternary Science Reviews |
container_volume |
29 |
container_issue |
23-24 |
container_start_page |
3045 |
op_container_end_page |
3056 |
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1768388142652456960 |