The complex hydrological signature of the Little Ice Age from the Puna to the Pampa reconstructed from lake records
by
Cecilia Laprida
Facultad de Ciencias Exactas y Naturales Universidad de Buenos Aires Intendente Güiraldes, Argentina
Coauthors: Blas Valero Garcés (Instituto Pirenaico de Ecología – CSIC, Spain), Norma Ratto (Universidad de Buenos Aires y Nacional de Catamarca, Argentina), Maria Julia Orgeira (FCEN, Universidad de Buenos Aires, Argentina), Ana Navas (Estación Experimental de Aula Dei-CSIC, Spain), Larry Edwards (University of Minnesota, USA), Emi Ito (LRC, University of Minnesota, Minneapolis, MN, USA), Antonio Delgado Huertas (Estación Experimental del Zaidin – CSIC, Spain), Ana Moreno (Instituto Pirenaico de Ecología – CSIC, Spain)

Water availability is one of the main factors controlling human activities in the arid and semiarid regions of South America. Paleohydrological reconstructions based on sedimentological, geochemical and biological records from lakes in the central–southern Altiplano and in the Argentinean Pampa indicate significant lake level fluctuations during recent centuries. A change to modern conditions occurred in the late 19th century in all the records, from northern Chile (Lago Chungará) and the Atacama (Laguna Miscanti) to the southern Puna (Laguna El Peinado) and the Pampa in the Buenos Aires province (Laguna Chascomús, L. del Monte, L. de los Padres, and L. Brava). 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. The increase in the frequency of extreme events may have played a role in the settlement and abandonment of archaeological sites in the Andean foothills as Batungasta (NW Argentina).

Lake and historical records correlate well in the Pampas, showing intense droughts during some intervals in the late 19th century and a general increase in lake levels during the 20th century. Despite regional differences and dating uncertainties, that must be further investigated, the Little Ice Age stands out as a significant and complex climatic event in the Andean Altiplano and the Pampas with profound hydrological consequences. The evidence for synchronous changes in both regions with different climatic regimes underlines large-scale climatic teleconnections. The structure of these recent paleohydrological changes may serve as analogs for past and future crises with more catastrophic consequences.

Date received: November 19, 2004