Lakes and Glaciers from Fuegian Andes. Morphology, Distribution and Origin

Abstract

The intense glacial activity produced in the Fuegian Andes during the Quaternary period generated numerous erosive glacial landforms with abundant depressions, many of which presently are occupied by glaciers and freshwater lakes. A characterization of these glaciers and lakes is presented based on their geomorphological distribution, morphology and origin. The glaciers in the argentinian sector of the Fuegian Andes occupy cirques placed between 880 and 1380 m a.s.l. and are less than 1 km2 in area. The lakes are distributed in cirques, glacial valleys, transfluence glacial surfaces (cols), interdrumlin areas, and on slopes and areas of scouring. Lakes are located between 17 and 1057 m a.s.l. and most of them have an area of less than 0.1 km2. The origin of lakes located in lower elevations goes back to glacial retreat after the Last Glacial Maximum. The lakes in hanging valleys would have developed after 11,700 yr cal. BP, when the glaciers retreated from moraines corresponding to the Younger Dryas. Cirque lakes would have been the last to develop. The presence of Little Ice Age moraines allows us to assign a relative age to some of these lakes. At present, new lakes continue to develop and appear in cirques as the glaciers retreat. These glaciers and lakes of the Fuegian Andes constitute geological resources of tourist and scientific interest, and serve as freshwater reservoirs, lending importance to their preservation and study.