Guallatiri is a stratovolcano in Chile that is 6,060–6,071 m (19,880–19,918 ft) high. It is located southwest of, or possibly within, the Nevados de Quimsachata volcanic group. The summit, surrounded by numerous fumaroles, may be a lava dome or volcanic plug, while the lower flanks of the volcano are covered by lava flows and lava domes. The volcano's eruptions have produced mostly dacite along with andesite and rhyolite. Past glaciation has left moraines on Guallatiri. A large eruption took place approximately 2,600 years ago. Guallatiri has been active since prehistoric times, with the latest known eruption in 1960. Fumarolic and seismic activity is ongoing and has resulted in the deposition of sulfur and other minerals on the volcano. It is covered by an ice cap above 5,500–5,800 m (18,000–19,000 ft) elevation that has retreated and broken up into separate ice bodies. Part of Lauca National Park, Guallatiri is monitored by the Chilean National Geology and Mining Service. (Full article...)