Cordón de Puntas Negras
| Cordón de Puntas Negras | |
|---|---|
Cordón de Puntas Negras seen from Laguna Miscanti with Cerro Miscanti in the foreground (left).
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| Highest point | |
| Elevation | 5,852 m (19,199 ft) |
| Coordinates | 23°44′34″S 67°32′03″W / 23.74278°S 67.53417°WCoordinates: 23°44′34″S 67°32′03″W / 23.74278°S 67.53417°W |
| Geography | |
| Location | Chile |
| Parent range | Andes |
| Geology | |
| Mountain type | Stratovolcanoes |
| Last eruption | Unknown |
Cordón de Puntas Negras is a 500 km2 (193 sq mi) volcanic chain located east of the Salar de Atacama in Chile's II Region.
Cordón de Puntas Negras is constructed along the major Calama–Olacapato–El Toro fault and is 70 kilometres (43 mi) long. The volcanic chain intersects with the Cordón Chalviri volcanic chain. Both chains cover a surface area of 500 square kilometres (190 sq mi) and contain cones, vents, lava domes, lava flows and maars, including a lava dome and silicic flow with a surface area of 13 square kilometres (5.0 sq mi). Puntas Negras specifically covers an area of 400 square kilometres (150 sq mi), which runs from the Chiliques volcano on the north to volcán Puntas Negras (5,852 m (19,199 ft)) almost to the SE. The Puntas Negras Volcano forms the common endpoint of two chains of volcanoes in a V-shaped configuration. The southern leg of the V is called "Cordón Chalviri" whose other extreme is the Cerro Tuyajto, SW of Puntas Negras and at the same distance SE of the Miñiques volcano. Several small volcanic centres and lava flows are found here, including Aguas Calientes, Cerros Cenizas, Chinchilla and Laguna Escondida which have well preserved craters. The volcanic chain is associated with a topographic anomaly in the region, a property that other volcanoes in the area also have.
Rocks in the chain are andesite, basaltic andesite and dacite. Magmas from this volcanic chain have a calc-alkaline composition formed by partial melting of a mantle wedge, with research indicating a decrease in SiO2 concentration over time.
The basement beneath the chain is composed from Ordovician marine sediments that were later deformed by the Acadian orogeny. The 35 by 70 kilometres (22 mi × 43 mi) La Pacana caldera is buried beneath Puntas Negras. Both the 3.2 ± 0.3 Patao ignimbrite and the 2.4 ± 0.4 mya Pampa Chamaca or Tuyajto ignimbrite from La Pacana may have been erupted from beneath Puntas Negras.
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