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294:. It has a volume of 26 cubic kilometres (6.2 cu mi) and its flow front is 400 metres (1,300 ft) high. Based on volumetric considerations, the eruption lasted about 100-150 years with an average lava flux rate of 25 cubic metres per second (880 cu ft/s). The volume of Chao is exceptional for a lava dome structure, although the lava flux rate generating it is low in comparison to a
374:. The ridges are drawn out on the western flow margin. The folds in the surface layers may have been caused by the surface stiffening more quickly than the underlying flow due to cooling. The flow surface is blocky, with blocks occasionally displaying flow banding. The lowest Chao I flow covers an area of 52 square kilometres (20 sq mi).
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from a long southbound flow with some lateral spillage. The flow itself is 14 kilometres (8.7 mi) long and its flow front is 400 metres (1,300 ft) high. Its structure is massive and lobate, with lobe diameters expanding downflow from 0.5 to 1.8 kilometres (0.31 to 1.12 mi). The flows are covered by
341:
and blocks. The northern side of the cone rises 100 metres (330 ft) from terrain while the southern side is partially breached. The highest point of the cone lies at 5,169 metres (16,959 ft) altitude. Its morphology suggests that it formed from a lava dome when it collapsed over the vent.
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apron that extends 3 by 4 kilometres (1.9 mi × 2.5 mi) from the flow front. Most of it is buried beneath the flow and only on the eastern side does some material emerge; its volume is estimated at 1 cubic kilometre (0.24 cu mi). This deposit is formed from several layers of
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domes. The formation of a lava flow instead of a lava dome may have been influenced by the formation of a carapace on the flow and the steep slopes the flows initially formed on; the late Chao III flow formed on the very gentle slope left by the previous Chao I and Chao II flows and shows some lava
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The flow proper is subdivided in three subunits, the first two named Chao I and Chao II. Originally subdivided because of their morphology, they most likely represent various pulses of the same eruption. They have a combined volume exceeding 22 cubic kilometres (5.3 cu mi) and are formed
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inclusions contained in the lava are characteristic for magma mixing processes. The eruption forming the flow may have been caused by the injection of andesite in a pre-existent homogenous dacitic magma chamber. The injection did presumably modify the crystallization processes in the magma chamber
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system lies on Cerro del León at 4,500 metres (14,800 ft) altitude. One of these moraines abuts Cerro Chao, indicating that the dome must be older than the moraine and thus older than the last glaciation 11,000 years ago. An active magmatic body may still exist under Cerro Chao and Paniri.
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The Chao III flow has a smaller volume of 2 cubic kilometres (0.48 cu mi) than Chao I and II. It has less ogives than Chao I and II and forms a single lobe, 150 metres (490 ft) high. The flow overlies the pumice cone and parts of the Chao II on its eastern side. A
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performed on rocks from the Chao I stage have indicated an average age of 423,000 ± 100,000 years. However, anomalous chemical compositions of the dated rocks suggest that they may overestimate the true age of the volcanics. Such alteration may be the result of the inclusion of
637:
Mancini, Renzo; Díaz, Daniel; Brasse, Heinrich; Godoy, Benigno; Hernández, María José (26 April 2019). "Conductivity distribution beneath the San Pedro‐Linzor volcanic chain, North Chile, using 3D magnetotelluric modeling".
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de Silva, S. L.; Self, S.; Francis, P. W.; Drake, R. E.; Carlos, Ramirez R. (1994). "Effusive silicic volcanism in the
Central Andes: The Chao dacite and other young lavas of the Altiplano-Puna Volcanic Complex".
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deposits to the south of the system. Most of the pyroclastics were formed during this phase, although some minor deposits formed from the collapse of the forming flow. A thin lapilli layer has been linked to
170:
between two volcanoes and advanced for a maximum length of 14 kilometres (8.7 mi). The eruption that originated the lava flows probably lasted more than one hundred years and occurred before the
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of the erupted lavas and its effusive nature. Conventional lava flows increase in viscosity with increasing crystal content; however Chao lava flows were erupted with similar viscosities and
242:
and La Torta. Cerro Chao lies within a northwest-running belt of volcanoes known as the San Pedro-Linzor volcanic chain, some of them over 6,000 metres (20,000 ft) high, of which
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are accessory minerals. Based on geochemical considerations, the magmas equilibrated at depths of 7–8 kilometres (4.3–5.0 mi) and temperatures of 840 °C (1,540 °F).
728:"Visualization of space competition and plume formation with complex potentials for multiple source flows: Some examples and novel application to Chao lava flow (Chile)"
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inclusions that are more numerous in the Chao III and upper Chao II stages, up to 5% of the volume of some Chao III lavas and vesiculated there. The lava has a
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of the
Altiplano-Puna volcanic complex, or may be the sign of a new injection of magmas in the crust. The significance of these theories is controversial.
370:(up to 30 metres (98 ft) high and with spacing of 50 by 100 metres (160 ft × 330 ft)) and some structures interpreted as fossil
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texture owing to its high crystal content of 45% and displays extensive flow banding. Chao III lavas have lower concentrations of crystals.
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silicic lava flow in the world. The vent location is related to an inferred fault zone emanating from one of the neighbouring volcanoes.
51:
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Cerro Chao formed over the course of three eruptions preceded by a pyroclastic stage. Three large lobate lava flows erupted in the
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eruptions occurred. In the present day, volcanism is of andesitic composition forming volcanic cones. Activity is controlled by
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The magmas that gave rise to Cerro Chao may either be the remnants of a previous magma body that gave rise to the neighbouring
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An overlapping pair of pyroclastic cones sits on top of the Chao flow and form its eruption vent. The cone has a
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Cerro Chao, also named Cerros de Chao, Chao lava or Chao volcano, is located in the volcanic front of the
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debris from the other flows. This flow has a surface area of 13 square kilometres (5.0 sq mi).
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formed above its vent and underwent several collapses, generating collapse scars. The flow is covered by
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234:. Neighbouring volcanoes with similar characteristics to Cerro Chao include Cerro Chanca/Pabellon,
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362:. Explosive activity continued during the extrusion of the Chao flow, growing the pumice cone.
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Guest, J. E.; Sánchez R, J. (September 1969). "A large dacitic lava flow in northern chile".
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has historical activity. Cerro Chao is the largest such silicic lava flow known.
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204:. The Central Volcanic Zone is one of the three volcanic belts in the Andes.
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silicic volcano body and part of the most recent phase of activity in the
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The eruption of Cerro Chao occurred in several phases. In a first phase,
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separated by erosion surfaces; at least one layer may be derived from
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and the volatiles in the magma to the point of forcing an eruption.
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volume of 0.5 cubic kilometres (0.12 cu mi) of
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16:Lava flow complex of Andes volcano Cerro del León
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249:The eruption is intriguing both in terms of the
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306:. This low flux rate is insufficient to cause
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732:Journal of Geophysical Research: Solid Earth
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640:Journal of Geophysical Research: Solid Earth
692:Earth environments past, present and future
402:composition, with some non-vesicular small
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695:. Hoboken, N. J.: Wiley. p. 369.
310:formation. Cerro Chao is the largest
689:Huddart, David; Stott, Tim (2013).
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482:Cerro Chascon-Runtu Jarita complex
236:Cerro Chascon–Runtu Jarita complex
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546:Journal of Geophysical Research
477:Altiplano–Puna volcanic complex
209:Altiplano–Puna volcanic complex
207:The region is dominated by the
161:Altiplano–Puna volcanic complex
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726:Weijermars, R. (March 2014).
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317:The flow is underpinned by a
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147:complex associated with the
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134:423,000 - 11,000 years ago.
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155:. It is the largest known
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33:The lava domes from space
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798:Global Volcanism Program
803:Smithsonian Institution
778:Oregon State University
774:volcano.oregonstate.edu
593:Bulletin Volcanologique
841:Pre-Holocene volcanism
831:Pleistocene lava domes
447:Potassium–argon dating
262:dome characteristics.
335:dense rock equivalent
184:Central Volcanic Zone
752:10.1002/2013JB010608
660:10.1029/2018jb016114
414:in the lava contain
398:The Chao flow is of
190:, between the older
744:2014JGRB..119.2397W
652:2019JGRB..124.4386M
605:1969BVol...33..778G
559:1994JGR....9917805D
353:activity generated
211:, where during the
63: /
826:Volcanoes of Chile
613:10.1007/BF02596749
487:List of lava domes
451:argon–argon dating
39:Highest point
702:978-1-118-68812-0
567:10.1029/94JB00652
360:San Pedro volcano
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114:Location in Chile
67:22.117°S 68.150°W
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793:"Cerro del Leon"
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424:plagioclase
412:Phenocrysts
319:pyroclastic
240:Chillahuita
225:fault zones
217:Pleistocene
130:Age of rock
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45:Coordinates
820:Categories
808:2021-06-29
498:References
456:xenocrysts
420:hornblende
384:weathering
312:Quaternary
221:ignimbrite
157:Quaternary
141:Cerro Chao
108:Cerro Chao
22:Cerro Chao
676:149491204
668:2169-9313
621:128832446
408:porphyric
404:andesitic
394:Petrology
386:-derived
380:lava dome
372:fumaroles
351:Vulcanian
330:volcano.
286:Structure
251:viscosity
244:San Pedro
199:andesitic
145:lava flow
83:Geography
471:See also
296:basaltic
280:calderas
272:andesite
238:, Cerro
172:Holocene
740:Bibcode
648:Bibcode
601:Bibcode
555:Bibcode
432:Apatite
416:biotite
400:dacitic
388:aeolian
347:Plinian
339:lapilli
324:pumices
308:caldera
304:Iceland
266:Origins
259:silicic
232:caldera
213:Miocene
186:of the
178:Geology
124:Geology
58:68°09′W
55:22°07′S
770:"Chao"
699:
674:
666:
619:
492:Paniri
436:zircon
428:quartz
368:ogives
328:Paniri
292:coulee
192:Paniri
672:S2CID
617:S2CID
188:Andes
153:Andes
143:is a
785:2015
710:2015
697:ISBN
664:ISSN
449:and
434:and
426:and
300:Laki
270:The
194:and
748:doi
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656:doi
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609:doi
563:doi
458:or
302:in
257:as
168:col
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460:K
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Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
