The Salta Puna

According to Wikipedia, the Puna de Atacama is an arid high plateau in the Andes with an average elevation of about 4,500 metres and an area of roughly 180,000 square kilometres. About 85 percent of it lies in northwestern Argentina, spread across the provinces of Salta, Jujuy and western Catamarca, and about 15 percent lies in northern Chile.

The Argentine and Chilean portions were not always divided as they are today. Before the War of the Pacific (1879 to 1883) the region belonged to Bolivia, and in 1898 Bolivia ceded it to Argentina in an exchange involving the recognition of Tarija as Bolivian. Chile objected, and the border was set in 1899 after the Puna de Atacama dispute, with Argentina receiving around 85 percent of the contested area.

Within Salta Province, the western highlands are described as a cool, semi-arid to arid zone with strong swings between day and night temperatures. Wikipedia gives daytime highs of roughly 14 to 21 degrees Celsius, with nights ranging from about 6 degrees in midsummer to well below freezing in midwinter. Rain falls mainly in summer and annual totals are low, which is why the plateau is dotted with salt flats rather than rivers.

Landmarks associated with the Argentine Puna include the Cono de Arita, a dramatic cone-shaped formation in Salta Province, and a string of high volcanoes such as Socompa, which straddles the Argentina-Chile border. The Salinas Grandes, a vast white salt flat shared between Jujuy and Salta at an average of about 3,450 metres above sea level, covers roughly 212 square kilometres according to Wikipedia. Lithium brine lies beneath its crust, and local Indigenous community leaders have objected to proposed lithium projects, arguing that their rights to use and control the land have been violated.

The Tren a las Nubes, or Train to the Clouds, is a heritage tourist railway on the Salta to Antofagasta line that climbs into the Puna toward San Antonio de los Cobres at about 3,775 metres. Wikipedia describes a line with 29 bridges, 21 tunnels, 13 viaducts, two spirals and two zigzags, though an Argentine press account counts 32 steel bridges, so bridge figures vary, reaching the curved La Polvorilla viaduct at about 4,220 metres. Planning for the railway began in the late nineteenth century, construction officially started in 1921, and the full line opened in 1948. Because operations have changed over the years, it is best to confirm current arrangements with the operator.

The wider region also has deep human history. Before the Spanish conquest the Atacama people lived on the Puna, and the Children of Llullaillaco, three frozen Inca mummies found on the Llullaillaco volcano, are now held in the Museum of High Altitude Archaeology in Salta city rather than on the plateau itself.

The Salta Puna is a place of long distances, thin air and sudden changes of scenery, so visits are usually planned as full days or longer and with attention to altitude. Dress for strong sun, wind and cold nights even in the warmer months. A private guided visit with a driver suits terrain where distances are large and viewpoints are far apart.