Milky Blue Glacier Lakes in Patagonia by Chile-Argentina Border49.5S 72.6W
Glacial lakes appearing bright blue in color can be observed in Patagonia by the Andes Mountains and the border between Chile (west) and Argentina (east). The lakes are, from top to bottom, Lake O’Higgins/San Martín (the former name is used in Chile, the latter in Argentina), Viedma Lake and Argentino Lake.
Lake O’Higgins / San Martín is located between the Aysén Region and the Santa Cruz Province. It has a surface area of 1,058 km², an elevation of 250 metres above mean sea level, and a shoreline length of 525 km. Viewed from above, the lake consists of a series of finger-shaped flooded valleys, of which 554 km² are in Chile and 459 km² in Argentina, although sources differ on the precise split, presumably reflecting water level variability. The lake is the deepest in the Americas with a maximum depth of 836 metres near O’Higgins Glacier, and its characteristic milky light-blue color comes from rock flour suspended in its waters.
Viedma Lake, approximately 50 miles (80 kilometers) long, is a major elongated trough lake formed from melting glacial ice. Lake Viedma is fed primarily by the Viedma Glacier at its the western end. The Viedma Glacier measures 3 miles (5 kilometers) wide at its terminus at Lake Viedma. The brown landscape is a result of ice scouring, which left virtually no vegetation on the steep-walled valleys. Water from lake Viedma flows into Lake Argentino through the La Leona River.
Lago Argentino is the biggest freshwater lake in Argentina, with a surface area of 1466 km2 (maximum width: 20 mi). It has an average depth of 150 m, and a maximum depth of 500 m. The lake lies within the Los Glaciares National Park, in a landscape with numerous glaciers and is fed by the glacial meltwater of several rivers, the water from Lake Viedma brought by the La Leona River, and many mountain streams. Its drainage basin amounts to more than 17000 km2.