Southern Patagonia Ice Field

The Southern Patagonian Ice Field (), located at the Southern Patagonic Andes between Chile and Argentina, is the world's second largest contiguous extrapolar ice field. It is the bigger of two remnant parts of the Patagonian Ice Sheet, which covered all of southern Chile during the last glacial period, locally called the Llanquihue glaciation.

Geography

The Southern Patagonian Ice Field extends from parallels 48° 15′ S to 51° 30′ S for approximately , and has an approximate area of , of which belong to Chile and belong to Argentina.

The ice mass feeds dozens of glaciers in the area, among which are the Upsala (), Viedma () and Perito Moreno () in the Los Glaciares National Park in Argentina, and the Pío XI Glacier or Bruggen Glacier (, the largest in area and longest in the southern hemisphere outside of Antarctica), O'Higgins (), Grey () and Tyndall () in Chile. The glaciers going to the west flow into the fjords of the Patagonian channels of the Pacific Ocean; those going to the East flow into the Patagonian lakes Viedma and Argentino, and eventually, through the rivers ''de la Leona'' and Santa Cruz, to the Atlantic Ocean.

An important part of the ice field is protected under different national parks, such as the Bernardo O'Higgins and Torres del Paine in Chile, and the aforementioned Los Glaciares in Argentina.

There are two known volcanoes under the ice field: Lautaro and Viedma. Due to their inaccessibility they are among the least researched volcanoes in Chile and Argentina.

In 1980, Chile planned Route 8 as a section of the Carretera Austral west of the ice field, which has not been built.

Circo de los Altares is an important hiking place.

History

Exploration

Thorough explorations include the expeditions of Federico Reichert (1913–1914), Alberto de Agostini (1931), and Harold William Tilman and Jorge Quinteros (1955–1956), as well as Eric Shipton (1960–61). The first (North-South) crossing of the field was accomplished in 1998 by Pablo Besser, Mauricio Rojas, José Montt, and Rodrigo Fica. Nevertheless, some areas of the field remain largely unexplored.

From the air, initial exploration was conducted in 1928–29 by Gunther Plüschow after whom a glacier is named. From April 1944 to April 1945, the United States Army Air Forces conducted an aerial survey using the Trimetrogon method at the request of the Chilean government.

Borderline

The boundary between Argentina and Chile in the area was established by the 1881 treaty and delimited in 1898 by the experts of both countries working in the demarcation of the border, and which differences led to the 1902 award, in which they agreed they did not have differences on the part of the border between Fitz Roy and Stokes. The award is established "to perpetuity" by both countries under British tutelage. The map published by the British Crown, as part of the documentation of the 1902 award, illustrates a clear demarcation line (from the Fitz Roy to the Stokes) to the east of the Southern Patagonian Ice Fields, leaving most of the territory in question in the Chilean side.

The 1902 award considered that in that area the high peaks are water dividing and therefore there was no dispute. Both experts, Francisco Pascasio Moreno from Argentina and Diego Barros Arana from Chile, agreed on the border between Mount Fitz Roy