stratovolcano
A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and per ...
in the
Antofagasta Region
The Antofagasta Region ( es, Región de Antofagasta, ) is one of Chile's sixteen first-order administrative divisions. The second-largest region of Chile in area, it comprises three provinces, Antofagasta, El Loa and Tocopilla. It is bordered t ...
of northern
Chile
Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...
. It was built on a basement of
ignimbrite
Ignimbrite is a type of volcanic rock, consisting of hardened tuff. Ignimbrites form from the deposits of pyroclastic flows, which are a hot suspension of particles and gases flowing rapidly from a volcano, driven by being denser than the surrou ...
s. A 7 km² silicic lava flow lies on the saddle between the volcano and
Acamarachi
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Acamarachi (also known as ''Pili'') is a high volcano in northern Chile. In this part of Chile, it is the highest volcano. Its name means "black moon". It is a volcano in the Central Volcanic Zone of the Andes, a zone of strong volcani ...
.
Colachi is part of a chain of stratovolcanoes stretching along the eastern side of the
Salar de Atacama
Salar de Atacama is the largest salt flat in Chile. It is located south of San Pedro de Atacama, is surrounded by mountains, and has no drainage outlets. In the east it is enclosed by the main chain of the Andes, while to the west lies a secondar ...
, the most active of which being
Lascar
A lascar was a sailor or militiaman from the Indian subcontinent, Southeast Asia, the Arab world, British Somaliland, or other land east of the Cape of Good Hope, who was employed on European ships from the 16th century until the middle of the 2 ...