Puna de Atacama: Atacama Plateau

The Puna de Atacama, or Atacama Plateau, is an arid high plateau in the Andes Mountains of northwestern Argentina (85%) and adjacent regions of Chile (15%).

This cold desolate Andean tableland is about 320 km (200 mi) long from north to south and 240 km (150 mi) wide from east to west. It has an average elevation of 3,300 - 4,000 m (11,000 - 13,000 ft).

The Puna de Atacama can be defined as the southernmost portion of the Andean Altiplano (or Puna) and is separated from the Atacama Desert in the west by the Cordillera Domeyko.

The Atacama Plateau region extends into Argentina's Salta, Jujuy and western Catamarca provinces. In Chile, it is included in Antofagasta and northeastern Atacama regions.

Temperatures average only 8.5 - 9.5 °C (47 - 49 °F), and most of the plateau region is dominated by a scanty growth of low shrub.

The peaks of the Cordillera Oriental alternate with dry, sandy, clay-filled basins containing salt pans (or salt flats) called salinas in Argentina, of which the largest are the Antofalla, Hombre Muerto, Arizaro, Incahuasi and Salinas Grandes. In Chile, the largest is the Atacama Salt Flat.

Streams dissect the eastern plateau into deep, narrow river valleys and broader valleys known as quebradas.

The region initially belonged to Bolivia but was ceded to Argentina in a territorial exchange. Chile, which had annexed the Litoral Province from Bolivia, declared the exchange illegal. The border was defined in 1899 after settling the Puna de Atacama dispute.

Since 1948, a railroad has linked the plateau from Salta, Argentina, in the west with the mining towns of the Atacama Desert in Chile to the east.

Today, the Puna de Atacama is sparsely populated with indigenous and mestizo communities dependent on the valleys for corn (maize) and wheat.