Resumo

RUIZ, Lucas  e  TROMBOTTO LIAUDAT, Darío. Glaciares de escombros fósiles en el cordón Leleque, Noroeste del Chubut: significado paleoclimático y paleográfico. Rev. Asoc. Geol. Argent. [online]. 2012, vol.69, n.3, pp.418-435. ISSN 0004-4822.

Fossil rock glaciers in the Cordón Leleque, Northwestern Chubut: Palaeoclimatic and palaeogeographic significance. The aim of this work was to document the current and past relationships between periglacial and glacial environments in the Andes from northern Patagonia (41° - 43° S). From the analysis and characterization of landforms related to permafrost and mountain glacial environments in combination with the analysis of climatic conditions and the use of present analogs, we provide a paleogeographic and paleoclimatic reconstruction of the Cordon Leleque from the Last Glaciation until present. The Cordón del Plata, a mountain range in the Central Andes presently covered by glaciers and rock glaciers was used as the modern analogue for the environmental conditions in the Cordón Leleque. Paleoclimatic conditions for the Cordón Leleque were derived from the current climate conditions in the Cordón del Plata. We used the relationship between the altitude of the regional equilibrium line of glaciers and the altitude of mountain permafrost limit, derived from the total annual rainfall and mean annual air temperature, to analyze the paleoclimatic evolution in the study area. The landform chronology was used to derive the paleogeographic and paleoclimatic reconstruction of the Cordón Leleque.

Palavras-chave : Mountain permafrost; Altitude of equilibrium line; Mountain permafrost limit; Isotherm 0° C.

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