Английская Википедия:Cordón del Azufre

Материал из Онлайн справочника
Перейти к навигацииПерейти к поиску

Шаблон:Short description Шаблон:Infobox mountain

Cordón del Azufre is an inactive complex volcano located in the Central Andes, at the border of Argentina and Chile. It consists of three stages of volcanic cones and associated lava flows, and its activity is a consequence of the subduction of the Nazca Plate underneath the South American Plate. North of it are the dormant volcano Lastarria and the actively uplifting Lazufre region.

Geoography and geology

The volcano, which is sometimes conflated with Lastarria,Шаблон:Sfn lies at the border between Argentina and ChileШаблон:Sfn and contains a series of lava flows and volcanic craters and lava flows,Шаблон:Sfn covering a surface area of Шаблон:Convert.Шаблон:Sfn Four craters are aligned in a north–south direction on a Шаблон:Convert ridge,Шаблон:SfnШаблон:Sfn which could reflect a north-south trending lineament.Шаблон:Sfn Numerous monogenetic volcanoes and stratovolcanoes developed on it and buried most of its central crater under lava flows. A pile of lava flows covers an area of Шаблон:Convert on the eastern side.Шаблон:Sfn The eastern component is formed by lava flows and craters in Argentina, and the youngest part la Moyra volcano in the western component generated a lava flow that advanced Шаблон:Convert westwardsШаблон:SfnШаблон:Sfn and another that ran Шаблон:Convert to the east.Шаблон:Sfn To the north lie the Plio-Pleistocene Atalaya volcano, followed by the Quaternary Azufre Oriental and Lastarria volcanoes,Шаблон:Sfn to the south the Plio-Pleistocene Chuta, the Quaternary Cerro Bayo Complex and the Los Colorados caldera.Шаблон:Sfn The area is uninhabitedШаблон:Sfn and remote,Шаблон:Sfn the climate arid, windy and with high temperature variations.Шаблон:Sfn

Cordón del Azufre is located Шаблон:Convert east of the Chile Trench, where the subduction takes place.Шаблон:Sfn At this latitude, the volcanic arc intersects a probably deep-seated structural area named the Archibarca corridor.Шаблон:Sfn Around Cordón del Azufre is a more local-scale raised region, as has been observed for some other CVZ volcanoes.Шаблон:Sfn The landscape is largely devoid of through-going drainages, as the extreme dryness and the frequent blockages by lava flows prevent its development.Шаблон:Sfn

Regional context and composition

Off the western coast of South America, the Nazca Plate subducts beneath the South American Plate. This subduction is responsible for volcanism in the Andean Volcanic Belt, including the Northern Volcanic Zone, the Central Volcanic Zone (CVZ), the Southern Volcanic Zone and the Austral Volcanic Zone.Шаблон:Sfn The CVZ extends over Peru, Bolivia, Chile and Argentina.Шаблон:Sfn Volcanic manifestations in the Central Andes include the numerous calderas and associated ignimbrites that form the Altiplano-Puna volcanic complex,Шаблон:Sfn such as La Pacana and Galán. There are about forty Quaternary volcanoes around Cordón del Azufre,Шаблон:Sfn which formed on top of Tertiary volcanic rocks.Шаблон:Sfn The region has grown to a high elevation since the Eocene.Шаблон:Sfn Basement rocks are Paleozoic volcanic and sedimentary rocks,Шаблон:Sfn and the large Pedernales-Arizaro thrust fault runs close to Cordón del Azufre.Шаблон:Sfn

Volcanic rocks include andesite and daciteШаблон:Sfn with a porphyritic appearance and hornblendeШаблон:Sfn and plagioclase inclusions.Шаблон:Sfn The rocks formed through interactions of ascending basaltic andesite with crustal material.Шаблон:Sfn The volcano is noted for its sulfur deposits,Шаблон:Sfn and the source of sulfur in Salar de Gorbea.Шаблон:Sfn

Eruption history

Volcanic rocks at Cordón del Azufre are less than one million years old.Шаблон:Sfn Activity has moved over time from the north-south craters to the eastern lava flows and vents and eventually to La Moyra.Шаблон:Sfn Lava flows of the eastern component have been dated to be 600,000 years old.Шаблон:Sfn No activity, including fumarolic activity, has been recorded at Cordón del Azufre,Шаблон:Sfn but the appearance (dark and pristine) and radiometric age (0.3 ± 0.3 mya K-Ar on the most recent flowШаблон:Sfn) of the lava flows suggest a recent ageШаблон:SfnШаблон:Sfn with Holocene activity.Шаблон:Sfn Pyroclastic deposits are linked to the youngest cone may date to a historical eruption. Renewed activity would likely consist of lava flows and pyroclastic deposits and, in light of the total lack of important roads and habitation, potential future eruptions are no threat.Шаблон:Sfn It is considered the 21st most dangerous volcano out of 38 in Argentina.Шаблон:Sfn

Шаблон:Main Beginning in 1996-1998,Шаблон:Sfn an ellipticШаблон:Sfn area of Шаблон:Convert has been uplifting.Шаблон:Sfn The centre of the uplifting area is between the volcanoes Lastarria and Cordón del Azufre, and has been named "Lazufre" after the acronym,Шаблон:Sfn but Cerro Bayo Gorbea is sometimes included in it.Шаблон:Sfn Lastarria, Cordón del Azufre and Cerro Bayo Gorbea form linear fissures that emanate from the centre of the Lazufre uplift,Шаблон:Sfn which is surrounded by a ring of Quaternary volcanoes and may be a developing caldera.Шаблон:Sfn The start of the uplift may be related to the occurrence of several tectonic earthquakes in the 1990s, such as the 1995 Antofagasta earthquake. They could have perturbed the magma chambers or opened up fractures.Шаблон:Sfn Magma influx has been stable Шаблон:As of.Шаблон:Sfn

This deformation system is among the largest on Earth,Шаблон:Sfn comparable with the size of calderas such as Long Valley and Yellowstone.Шаблон:Sfn There are several Pleistocene volcanoes around the uplift region, which may be supplied from the sill.Шаблон:Sfn Magnetotelluric data show a zone with high electrical conductivity that rises from the mantle into the crust, and may be the magma supply to Lazufre.Шаблон:Sfn Research published in 2016 indicated that the uplift has been ongoing since at least 400,000 years, based on the deformation of lava flows and volcanoes erupted within this time period. Depending on the highly uncertain estimates for the volume of the magma chamber, a modest overpressure may be sufficient to cause the roof of the chamber to fail and an eruption to start.Шаблон:Sfn

See also

References

Шаблон:Reflist

Sources

Шаблон:Refbegin

Шаблон:Refend

Шаблон:Andean volcanoes

Партнерские ресурсы
Криптовалюты
Магазины
Хостинг
Разное

Источник — http://wikihandbk.com/ruwiki/index.php?title=Английская_Википедия:Cordón_del_Azufre&oldid=14069746