Abrupt warming events recorded in Greenland ice cores known as Dansgaard-Oeschger (DO) interstadials are linked to changes in tropical circulation during the last glacial cycle. Corresponding variations in South American summer monsoon (SASM) strength are documented, most commonly, in isotopic records from speleothems, but less is known about how these changes affected precipitation and Andean glacier mass balance. Here we present a sediment record spanning the last ~50 ka from Lake Junín (Peru) in the tropical Andes that has sufficient chronologic precision to document abrupt climatic events on a centennial-millennial time scale. DO events involved the near-complete disappearance of glaciers below 4700 masl in the eastern Andean cordillera and major reductions in the level of Peru’s second largest lake. Our results reveal the magnitude of the hydroclimatic disruptions in the highest reaches of the Amazon Basin that were caused by a weakening of the SASM during abrupt arctic warming. Accentuated warming in the Arctic could lead to significant reductions in the precipitation-evaporation balance of the southern tropical Andes with deleterious effects on this densely populated region of South America.
Bibliographical noteFunding Information:
We recognize the late G.O. Seltzer for his seminal work on the Junín Plain. We are grateful to Lake Junín Drilling Project members for their contributions to fieldwork and data collection, the International Continental Drilling Program (ICDP) for financial and logistical support, and DOSECC Exploration Services and Geotec Peru for drilling expertise. We thank LacCore for access to facilities, core curation, XRF analyses, and data management. This research was supported by grant 02–2012 from the ICDP and awards EAR-1404113 (Abbott), EAR-1402076 (Rodbell), EAR-1400903 (Stoner), EAR-1404414 (McGee), and EAR-1402054 (Bush) from the U.S. National Science Foundation Paleo Perspectives on Climate Change Program.
© 2020, The Author(s).
Copyright 2020 Elsevier B.V., All rights reserved.
PubMed: MeSH publication types
- Journal Article
- Research Support, U.S. Gov't, Non-P.H.S.
- Research Support, Non-U.S. Gov't