Reconstrucciones paleolimnológicas desde el Último Máximo Glacial en el sur de Sudamérica: ¿megasistemas en antifase hidrológica?

PIOVANO, E.; ARIZTEGUI, D.; CIOCCALE, M.; CÓRDOBA, F.; ZANOR, G.

Córdoba

Congreso; III Congreso Argentino de Cuaternario y Geomorfología; 2006

Asociación Argentina de Cuaternario y Geomorfología

We reviewed the most significant published limnogeological records throughout a wide geographical range and climate regimes: a) Pampean plains; b) Andean Altiplano and Puna; and c) Northern Andean Patagonia and Extra Andean Southern Patagonia. Southern South America climate archives show a complex pattern of timing and climate variability since the Last Glacial Maximum. There is, however, a noticeable antiphased hydrological balance at both sides of the Arid Diagonal, which extends across Argentina from the Atlantic coast at ca. 40-42° S up to the eastern flank of the Central Andes at 25-27° S. Numerous paleohydrological reconstructions -based on sedimentological, geochemical, and isotope proxies- suggest high lake levels and, hence, wet conditions during cold phases in Patagonia, excepting the LGM, as well as part of the Central Andes. Conversely, warm climate phases in the Pampean plains and in Altiplano were represented by high lake levels. The antiphased cold-wet vs. cold-dry hydrological conditions at different latitudes reveal that increased rainfall triggered by intensified Westerlies in Patagonia and Central Andes are synchronous with dry conditions resulting from a diminished monsoonal activity in the subtropics.Conversely, an intensified monsoonal regime (warm-wet in the Pampas) is correlated with diminished southern westerlies (warm-dry conditions in Patagonia and Puna).