In January 2003, shallow firn cores were recovered from Glaciar Esmeralda on Cerro del Plomo (33°14′ S, 70°13′ W; 5300ma.s.l.), central Chile, and from Glaciar La Ollada on Cerro Mercedario (31°58′ S, 70°07’W; 6070ma.s.l.), Argentina, in order to find a suitable archive for paleoclimate reconstruction in a region strongly influenced by the El Niño–Southern Oscillation. In the area between 28° S and 35° S, the amount of winter precipitation is significantly correlated to the Southern Oscillation Index, with higher values during El Niño years. Glaciochemical analysis indicates that the paleo-record at Glaciar La Ollada is well preserved, whereas at Glaciar Esmeralda the record is strongly influenced by meltwater formation and percolation. A preliminary dating of the Mercedario core by annual-layer counting results in a time-span of 17 years (1986–2002), yielding an average annual net accumulation of 0.45mw.e.

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