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Sci Adv. 2018 Aug 29;4(8):eaar2514. doi: 10.1126/sciadv.aar2514. eCollection 2018 Aug.

Lake Tauca highstand (Heinrich Stadial 1a) driven by a southward shift of the Bolivian High.

Author information

1
Centre de Recherches Pétrographiques et Géochimiques, UMR 7358 CNRS-Université de Lorraine, 54500 Vandœuvre-lès-Nancy, France.
2
Department of Geosciences, University of Oslo, P.O. Box 1047, Blindern, 0316 Oslo, Norway.
3
Laboratoire de Glaciologie, Département Géosciences, Environnement et Société-Institut des Géosciences, Université Libre de Bruxelles, 1050 Brussels, Belgium.
4
Université de Grenoble Alpes, Institut de Recherche pour le Développement (IRD), CNRS, Institut des Géosciences de l'Environnement, F-38000 Grenoble, France.
5
Université Paris 1 Panthéon-Sorbonne, CNRS Laboratoire de Géographie Physique, 92195 Meudon, France.
6
ETH, Geological Institute, Sonneggstrasse 5, 8092 Zurich, Switzerland.

Abstract

Heinrich events are characterized by worldwide climate modifications. Over the Altiplano endorheic basin (high tropical Andes), the second half of Heinrich Stadial 1 (HS1a) was coeval with the highstand of the giant paleolake Tauca. However, the atmospheric mechanisms underlying this wet event are still unknown at the regional to global scale. We use cosmic-ray exposure ages of glacial landforms to reconstruct the spatial variability in the equilibrium line altitude of the HS1a Altiplano glaciers. By combining glacier and lake modeling, we reconstruct a precipitation map for the HS1a period. Our results show that paleoprecipitation mainly increased along the Eastern Cordillera, whereas the southwestern region of the basin remained relatively dry. This pattern indicates a southward expansion of the easterlies, which is interpreted as being a consequence of a southward shift of the Bolivian High. The results provide a new understanding of atmospheric teleconnections during HS1 and of rainfall redistribution in a changing climate.

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