Timing of the last Deglaciation in the Sierra Nevada of the Mérida Andes, Venezuela
| Autor: | Isandra Angel, Christian Beck, Eduardo Carrillo, Franck Audemard, Julien Carcaillet |
|---|---|
| Rok vydání: | 2013 |
| Předmět: |
010506 paleontology
geography geography.geographical_feature_category 010504 meteorology & atmospheric sciences Oldest Dryas Glacial landform Older Dryas 01 natural sciences Paleontology Arts and Humanities (miscellaneous) Moraine Deglaciation General Earth and Planetary Sciences Glacial period Younger Dryas Geomorphology Holocene Geology 0105 earth and related environmental sciences Earth-Surface Processes |
| Zdroj: | Quaternary Research. 80:482-494 |
| ISSN: | 1096-0287 0033-5894 |
| Popis: | In the tropical Mérida Andes (northwestern Venezuela), glacial landforms were found at altitudes between 2600 and 5000 m, corresponding to 600 km2 of ice cover during the maximum glacial extension. However, the lack of sufficient absolute age data prevents detailed reconstruction of the timing of the last deglaciation. On the northwestern flank of the Mucuñuque Massif, successive moraines and striated eroded basement surfaces were sampled for cosmogenic 10Be investigation. Their compilation with published data allows the establishment of a detailed chronology of the post-LGM glacier history. The oldest moraines (18.1 and 16.8 ka) correspond to the Oldest Dryas. Successive moraine ridges indicate stops in the overall retreat between the LGM and the Younger Dryas. The cold and short Older Dryas stadial has been identified. Results indicate that most of the ice withdrew during the Pleistocene. The dataset supports an intensification of the vertical retreat rate from ~ 25 m/ka during the late Pleistocene to ~ 310 m/ka during the Pleistocene/Holocene. Afterwards, the glacier was confined and located in the higher altitude zones. The altitude difference of the Younger Dryas moraines in the Mucubají, La Victoria and Los Zerpa valleys indicates a strong effect of valley orientation on the altitude of moraine development. |
| Databáze: | OpenAIRE |
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