Antarctic-like temperature variations in the Tropical Andes recorded by glaciers and lakes during the last deglaciation - CNRS - Centre national de la recherche scientifique Accéder directement au contenu
Article Dans Une Revue Quaternary Science Reviews Année : 2020

Antarctic-like temperature variations in the Tropical Andes recorded by glaciers and lakes during the last deglaciation

Résumé

The respective impacts of Northern and Southern Hemispheric climatic changes on the Tropics during the last deglaciation remain poorly understood. In the High Tropical Andes, the Antarctic Cold Reversal (ACR, 14.3-12.9 ka BP) is better represented among morainic records than the Younger Dryas (12.9-11.7 ka BP). However, in the Altiplano basin (Bolivia), two cold periods of the Northern Hemisphere (Heinrich Stadial 1a, 16.5-14.5 ka BP, and the Younger Dryas) are synchronous with (i) major advances or standstills of paleoglaciers and (ii) the highstands of giant paleolakes Tauca and Coipasa. Here, we present new cosmic ray exposure (CRE) ages from glacial landforms of the Bolivian Andes that formed during the last deglaciation (Termination 1). We reconstruct the equilibrium line altitudes (ELA) associated with each moraine and use them in an inverse algorithm combining paleoglaciers and paleolake budgets to derive temperature and precipitation during the last deglaciation. Our temperature reconstruction (ΔT relative to present day) yields a consistent regional trend of progressive warming from ΔT = −5 to −2.5°C during 17-14.5 ka BP, followed by a return to colder conditions around −4°C during the ACR (14.5-12.9 ka BP). The Coipasa highstand (12.9-11.8 ka BP) is coeval with another warming trend followed by ΔT stabilization at the onset of the Holocene (ca. 10 ka BP), around −3°C. Our results suggest that, during the last deglaciation (20-10 ka BP) atmospheric temperatures in the Tropical Andes mimicked Antarctic variability, whereas precipitation over the Altiplano was driven by changes in the Northern Hemisphere.
Fichier principal
Vignette du fichier
Altiplano_postRev84_noColor.pdf (4.62 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)

Dates et versions

hal-03029770 , version 1 (02-12-2020)

Licence

Paternité - Pas d'utilisation commerciale - Pas de modification

Identifiants

Citer

L. C P Martin, P.-H Blard, J Lavé, Vincent Jomelli, J. Charreau, et al.. Antarctic-like temperature variations in the Tropical Andes recorded by glaciers and lakes during the last deglaciation. Quaternary Science Reviews, 2020, 247, pp.106542. ⟨10.1016/j.quascirev.2020.106542⟩. ⟨hal-03029770⟩
184 Consultations
184 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More