Llullaillaco

Llullaillaco
Llullaillaco from the east
Highest point
Elevation	6,739 m (22,110 ft)
Prominence	2,344 m (7,690 ft)
Listing	Ultra
Coordinates	24°43′00″S 68°32′00″W / 24.71667°S 68.53333°W / -24.71667; -68.53333[1]
Geography
Llullaillaco Location in Chile (on border with Argentina)
Location	Chile and Argentina
Parent range	Andes, Puna de Atacama
Geology
Age of rock	Pleistocene
Mountain type	Stratovolcano
Last eruption	May 1877[2]
Climbing
First ascent	1950, but previous climbs by Inca

Llullaillaco (Spanish pronunciation: [ʎuʎajˈʎako]) is a dormant stratovolcano on the border between Argentina (Salta Province) and Chile (Antofagasta Region). It lies in the Puna de Atacama, a region of tall volcanic peaks on a high plateau close to the Atacama Desert, one of the driest places in the world. Its maximum elevation is most commonly given as 6723 m, making it the second- or third-highest volcano in the world. Despite its height, it is not clear whether the volcano has any glaciers or merely patches of perennial snow and ice. Between 3700 m and 5000 m elevation there is a sparse plant cover, while at lower altitudes the climate is too dry for plants to grow. A species of mouse on Llullaillaco is the highest-living known vertebrate species.

The volcano formed during the Pleistocene in two stages, named Llullaillaco I and Llullaillaco II. The oldest rocks are about 1.5 million years old. About 150,000 years ago, the volcano's southeastern flank collapsed, generating a debris avalanche that reached as far as 25 km from the summit. During the last stage, three conspicuous lava flows were emplaced on the summit. The youngest dated rocks are 930 ± 140 years old, but there are reports of activity from the 19th century.

The mountain's first recorded climb was in 1950, but traces of earlier climbs and a number of archaeological sites were found on the mountain and at its feet; Llullaillaco marks the highest archaeological site in the world. In 1999, the mummified remains of three children, known as the Children of Llullaillaco, were found at its summit. They are presumed to have been human sacrifices.