Paleohydrological reconstructions based on sedimentological, geochemical, and isotopic records from a lake transect in the central-southern Altiplano (18°-26°S) indicate abrupt moisture fluctuations during the last 500 years. A change to modern conditions occurred in the late 19th century in all the records, from northern Chile (Lago Chungará, 18°15′S) and the Atacama (Laguna Miscanti, 23°45′S) to the southern tip of the Altiplano (Laguna El Peinado, NW Argentina, 26°30′S). A previous drier period shows different patterns of timing, duration, and intensity. In Chungará, the arid period was shorter and occurred during the late 19th and early 20th centuries, while in Miscanti, it occurred earlier and ended at the beginning of the 20th century. In El Peinado, conditions were wetter during the 17-19th centuries and the arid period occurred prior to the 17th century. Other records from the region show abrupt paleohydrological and paleoclimatic changes synchronous with the termination of the Little Ice Age. Despite local differences and dating uncertainties, the Little Ice Age stands out as a significant though complex climatic event in the Andean Altiplano. The discrepancies between the northern and southern Altiplano records during the last few centuries may reflect contrasting responses to external forcing in two areas with different climatic regimes.
Bibliographical noteFunding Information:
The research work in Laguna Miscanti and Chungará was part of the Swiss National Science Foundation Project ‘Global Change in the Arid Andes’ (SNF-20-36382.92) led by the University of Bern, Switzerland. The Universidad Nacional de Catamarca (Argentina) and the Departamento de Relaciones Internacionales, CSIC (Spain) financially supported the fieldwork in Argentina. The 210 Pb dating was performed by Dan Engstrom, University of Minnesota. Coring equipment and core lab facilities were provided by the Limnological Research Center, University of Minnesota, and short-coring apparatus and sediment extruder by Dirk Verschuren. Caspar Amman provided the rainfall data for the Chungará region. We thank Geoffrey Seltzer and two anonymous reviewers for their comments and criticisms that improved the manuscript. We are deeply grateful to Kerry Kelts (Limnological Research Center, University of Minnesota, USA) who inspired us with trust to go to the Atacama Altiplano in 1993 and to start lake studies in that remote region. He passed away on February 2001 and this paper is dedicated to him.