Chillahuita is a
dacitic
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. ...
lava dome
In volcanology, a lava dome is a circular mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. Around 6% of eruption ...
in 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 eas ...
. It may have formed after the
Pleistocene
The Pleistocene ( , often referred to as the '' Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed ...
,
although
argon-argon dating on
amphibole
Amphibole () is a group of inosilicate minerals, forming prism or needlelike crystals, composed of double chain tetrahedra, linked at the vertices and generally containing ions of iron and/or magnesium in their structures. Its IMA symbol is ...
has indicated an age of 370,000 ±40,000 years.
It has an altitude of about . It formed in a single non-
explosive eruption
In volcanology, an explosive eruption is a volcanic eruption of the most violent type. A notable example is the 1980 eruption of Mount St. Helens. Such eruptions result when sufficient gas has dissolved under pressure within a viscous magma s ...
.
The flow moved northward and eastward from the vent over a terrain with slopes of 3-4°. The flow has a surface area of with a flat circular surface containing flow folds. Steep high flanks limit the flow, which has a total volume of . It is surrounded by a
pumice
Pumice (), called pumicite in its powdered or dust form, is a volcanic rock that consists of highly vesicular rough-textured volcanic glass, which may or may not contain crystals. It is typically light-colored. Scoria is another vesicular v ...
deposit probably from the
San Pedro volcano to the northwest.
The eruption of the Chillahuita dome appears to have been controlled by local
fault systems associated with the
Altiplano-Puna volcanic complex, which also has geochemical similarity with Chillahuita lavas.
See also
*
Cerro Chao
Cerro Chao is a lava flow complex associated with the Cerro del León volcano in the Andes. It is the largest known Quaternary silicic volcano body and part of the most recent phase of activity in the Altiplano–Puna volcanic complex.
Cerro Ch ...
*
Cerro Chascon-Runtu Jarita complex
Cerro Chascon-Runtu Jarita is a complex of lava domes located inside, but probably unrelated to, the Pastos Grandes caldera. It is part of the more recent phase of activity of the Altiplano-Puna volcanic complex.
Accompanied with little explosiv ...
References
External links
*{{cite web, title=Chillahuita, url=http://volcano.oregonstate.edu/oldroot/CVZ/chillahuita/index.html, website=Volcano World, publisher=
Oregon State University
Oregon State University (OSU) is a Public university, public Land-grant university, land-grant, research university in Corvallis, Oregon. OSU offers more than 200 undergraduate-degree programs along with a variety of graduate and doctoral degree ...
, accessdate=19 November 2015
Volcanoes of Antofagasta Region
Pleistocene lava domes