Antofalla is a Miocene-Pliocene volcano in Argentina's Catamarca Province. It is part of the volcanic segment of the Andes in Argentina, and it is considered to be part of the Central Volcanic Zone, one of the volcanic zones of the Andes. Antofalla forms a group of volcanoes that are aligned on and behind the main volcanic arc. Antofalla itself is a remote volcano.
Antofalla and other Andean volcanoes form because the Nazca Plate is subducting beneath the South American Plate. Antofalla volcano is located in a region with a "basins and ranges" topography, where during the Miocene ranges were uplifted and basins formed through tectonic movement. It sits on a basement formed by Eocene-Miocene sedimentary units over a much older crystalline basement.
Antofalla is formed by a principal volcano, the high Antofalla volcano proper, and a surrounding complex of smaller volcanic systems that are formed by lava flows and pyroclastic material. The whole complex was active between 10.89–1.59 million years ago; whether activity occurred in historical time is unclear.
Name
The mountain is first attested in a map of 1900 as Antofaya, although an earlier map in 1632 uses the name Antiofac for the whole region. The name may be derived from , , , which means "metal" (especially "copper") in the indigenous language Quechua. Pedro Armengol Valenzuela hypothesized that the second part of the name is , "collect"; thus the name Antofalla would mean "collection of copper". Another theory is that Antofalla is derived from the Diaguita language.
Geography and structure
Antofalla lies in the Antofagasta de la Sierra department of the northern Catamarca Province, in northwestern Argentina. The towns of Antofalla, Puesto Cuevas, Botijuela and Potrero Grande are east, southeast, south and southwest of the volcano, respectively. Gravel roads run along the northern, northeastern and east-southeast-southern sides of the volcanic complex, but the volcano is difficult to access. Precolumbian constructions, including a platform on the summit of Antofalla, have been found.
Antofalla is part of the Central Volcanic Zone of the Andes, which runs along the border between Argentina and Chile and whose main expression occurs in the Western Cordillera. The volcanoes of the Central Volcanic Zone lie at high altitudes, and the volcanic zone spans the countries of Argentina, Bolivia, Chile and Peru. Present-day activity in the Central Volcanic Zone occurs at Lascar and Lastarria, and about 44 centres have been active in the Holocene. Aside from stratovolcanoes, calderas with large ignimbrites are also part of the Central Volcanic Zone; the Altiplano–Puna volcanic complex is a complex of such large calderas.
Antofalla is a cluster of stratovolcanoes, with the high Antofalla volcano at its centre. An altar with a stone pyramid lies on its summit, and the mountains Llullaillaco, Pajonales and Pular can be seen from the top of the mountain.
A number of other centres developed around the main Antofalla volcano, forming a wide volcanic area; counterclockwise from the north these are: high Cerro Onas high Cerro Patos (with the neighbouring high Cerro Ojo de Antofalla) or high Cerro Lila or high Cerro Cajeros or high Cerro de la Aguada, also known as Cerro Botijuelas Cerro Bajo-Cerro Onas high Conito de Antofalla. These volcanic centres overlap with each other, are all much smaller than the main Antofalla volcano and have experienced little erosion. All these volcanoes are formed by lava domes, lava flows and pyroclastic units. Ignimbrites are also found and one of these forms Cerro Onas, while a more recent one occurs in the Quebrada de las Cuevas area. Between Cerro de la Aguada and Cerro Cajeros lies the Cerro la Botijuela obsidian dome. On the western and southwestern side of the complex, some cinder cones can be found, and fissure vents linked to faults cut through the volcanic complex. Finally, a sector collapse deposit and collapse amphitheatre can be observed at Quebrada de las Minas and Quebrada el Volcán. A large scale topographic anomaly surrounds the entire volcanic complex, and seismic tomography has shown the presence of low-velocity anomalies linked to the volcanic group.