caldera
A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcano eruption. When large volumes of magma are erupted over a short time, structural support for the rock above the magma chamber is ...
in the
Andes
The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S ...
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 ...
which was discovered in 1975.
It has a diameter of and formed during the
Pliocene
The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58K-Ar date of 3.6 ± 0.1 million years ago. It has erupted
dacite
Dacite () is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite ...
and rhyolite. The caldera and the associated stratovolcano of the same name are an important source of obsidian, which forms several large lava flows. This obsidian is known as the ''Laguna Blanca obsidian'' or ''
Zapaleri
Zapaleri is a volcano whose summit is the tripoint of the borders of Argentina, Bolivia and Chile. A number of railways are in the area. It is part of Potosí Department (Bolivia), Jujuy Province (Argentina), and Antofagasta Region (Chile). The ...