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= Guallatiri =
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Introduction
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Guallatiri is a volcano in Chile with an elevation of 6060 to. It is
located southwest of the Nevados de Quimsachata volcanic group; some
sources classify Guallatiri as a member. Guallatiri is a stratovolcano
with numerous fumaroles around the summit. The summit may be a lava
dome or volcanic plug, while the lower flanks of the volcano are
covered by lava flows and lava domes. The volcano's eruptions have
produced mostly dacite along with andesite and rhyolite. Past
glaciation has left moraines on Guallatiri.
A large eruption took place approximately 2,600 years ago. Guallatiri
has been active in historical times with a number of eruptions, the
latest in 1960. Fumarolic and seismic activity is ongoing and has
resulted in the deposition of sulfur and other minerals on the
volcano. The volcano is covered by an ice cap above 5500 to that has
shrunk and fragmented during the course of the 20th and 21st
centuries. Guallatiri, along with several other volcanoes, is part of
Lauca National Park and is monitored by the Chilean National Geology
and Mining Service (SERNAGEOMIN).
Name and ascents
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The term Guallatiri is derived from , which means in Aymara,
referring to the birds' frequent occurrence in the area. Other names
are (also an Aymara word), Huallatiri, Huallatire and Guallatire. It
was first climbed in 1926 by the geologist . The volcano is considered
to be easy to ascend (rated F on the French Climb grading by John
Biggar) but toxic gases constitute a hazard in the summit region.
Geography and geomorphology
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The volcano lies in the Putre municipality, Arica y Parinacota Region.
It is located south of Lake Chungará
and 4 km west of Cerro Capurata. The latter is part of the Nevados de
Quimsachata volcano chain which includes Umurata, Acotango and
Capurata; sometimes Guallatiri is considered to be part of the Nevados
de Quimsachata. The older Umurata and Acotango volcanoes are heavily
eroded; Capurata is better preserved. Guallatiri is part of the larger
Western Cordillera, the western boundary of the Altiplano high
plateau.
The small town of Guallatiri is 9.5 km southwest of the volcano and is
the settlement closest to it; the town has a 17th-century church and
a refuge of the National Forest Corporation. Other nearby towns
include Ancuta, Carbonire and Churiguaya. each had a population of
less than 25 people. The provincial capital Putre is 55 km north of
the volcano, and 130 km farther west, on the Pacific coast, is Arica.
Economic activity in the area includes the Tambo Quemado border
crossing, agriculture, animal husbandry, tourism and mountaineering,
including ascents to the summit of Guallatiri. There are no known
archeological sites on the summit of Guallatiri, unlike several other
mountains in the region. Possible reasons are the continuous ice cover
and the constant volcanic activity. The frontier between Bolivia and
Chile runs along the Nevados de Quimsachata northeast of Guallatiri,
not far from the volcano. The volcano is remote and thus poorly known.
The volcano
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Guallatiri is 6060 m or 6071 m high; claims of even higher elevations
appeared in past and some recent publications. It is a composite
volcano or stratovolcano with a symmetric cone surmounted by a lava
dome, lava complex or volcanic plug and a vent just south of it.
Lava domes, lava flows, tephra and volcanic ash make up the mountain.
Guallatiri rises about 1.7 km above the surrounding terrain and covers
an area of about 85 km2; the total volume is about 50 km3. Thick lava
flows emanate in all directions but are primarily noted on the
northern and western flanks. The flows reach thicknesses of 230 m and
lengths of 8 km. The lava flows have a lobate appearance even when
they are heavily eroded, and display levees, ogives, polygonal cracks
and blocky surfaces. Older flows have been eroded into hills.
Block-and-ash flows form fans on the southern and southwestern flanks.
Tephra deposits are mainly located on the eastern and southern side of
Guallatiri. Tuffs and pyroclastic flow deposits occur both in the
summit region and in radial valleys that emanate from Guallatiri,
although some of the deposits southwest of the volcano have been
reinterpreted as being reworked sediments. Apart from volcanic rocks,
glacial deposits cover large parts of the volcano, and there are
traces of mass failures.
On the southern flank, there are two lava domes named Domo Tinto and
Domo Sur; other than these Guallatiri has no lateral vents. Domo Tinto
is 100 m wide and 100 m high while Domo Sur (1.5 km southwest of Domo
Tinto) is 120 m thick and 750 m wide. Domo Tinto has a hummocky
surface and resembles a pancake.
There are both cold springs and hot springs on Guallatiri, indicating
that groundwater interacts with the magmatic system. One hot spring is
located at Chiriguaya on the northwestern foot of Guallatiri, where
temperatures of 48 C were measured in bubbling pools, and sinter
deposition takes place. Several streams run off the mountain; they
eventually enter Lake Chungará and the Lauca River.
Ice
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Above 5500 m-5800 m elevation the volcano is covered with ice. , an
ice cap on Guallatiri covered an area of 0.796 km2 and had a volume of
0.026 km3. Ice area has been retreating at a rate of 0.07 km2/year
(between 1988 and 2017), leading to the breakup of the ice cap into
several separate ice bodies. According to a 2005 study by Rivera 'et
al.', heat emitted by fumaroles may have contributed to the enhanced
melting of the ice.
Glacial deposits on Guallatiri cover an area of about 80 km2 above
4650 m elevation, with lateral moraines reaching lengths of 2 km and
thicknesses of 15 m. Glaciers reached their maximum extent between
13,500 and 8,900 years ago. This is unlike the global Last Glacial
Maximum (LGM), which peaked between 21,000 and 19,000 years ago. This
is a consequence of the climate in the region, where glacier extent
was more sensitive to increased moisture supply than to decreasing
temperatures; presumably the global LGM was too dry to allow glacier
formation. Some glaciers were still present during the Holocene,
evidenced by Holocene-age Domo Tinto lava dome which bears traces of
glacial erosion and is partially covered by moraines.
Volcanic units are found both overlying and underlying glacial
deposits such as moraines. Older volcanic rocks bear glacial
striations, and volcanic bombs on the lower flanks may have been
transported there by glaciers.
Geology
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Off the western coast of South America, the Nazca Plate subducts
beneath the South American Plate at a rate of about 7 -. The
subduction process is responsible for the volcanism of the Northern
Volcanic Zone, Central Volcanic Zone (CVZ) and Southern Volcanic Zone,
and has also driven the formation of the Altiplano during the last 25
million years.
The CVZ is a 1500 km long chain of volcanoes spanning southern Peru,
northern Chile, western Bolivia and northwestern Argentina. It
contains about 58 active or potentially active volcanoes, 33 of which
are located within Chile. The most active CVZ volcano is Lascar, which
in 1993 produced the largest historical eruption of northern Chile.
Guallatiri rises above Oligocene to Pliocene age volcanic and
sedimentary rocks, which define the Lupica and Lauca Formations. The
Lupica Formation is older and consists mainly of volcanic rocks, while
the Lauca Formation is formed by volcanic and sedimentary rocks that
were deposited within the basin and in part altered by glaciers.
Archean to Precambrian-Paleozoic rocks make up the basement. There is
evidence that the terrain was tectonically active during the
Quaternary.
Composition
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The composition of Guallatiri's rocks ranges from andesite over dacite
to rhyolite, with dacites being predominant. The summit dome is formed
by dacite and most outcrops are trachyandesite and trachydacite. The
rocks define a potassium-rich calc-alkaline suite and contain
amphibole, apatite, biotite, clinopyroxene, olivine and plagioclase
phenocrysts, similar to other volcanoes in the region. A single lava
bomb made out of obsidian has been found. Mafic rock enclaves have
been observed in Domo Tinto rocks, which indicate that mafic magmas
were injected into the magma chamber and mixed with already present
magma. Fractional crystallization and magma mixing processes gave rise
to Guallatiri's magmas.
Fumaroles have deposited minerals such as anhydrite, baryte,
cristobalite, gypsum, quartz, sassolite and sulfur. Less common are
galena, orpiment and pyrite. Sulfur deposits have yellow, orange or
red colours and are sometimes accompanied by arsenic-sulfur compounds
that also contain iodine, mercury, selenium and tellurium. Sulfur
deposits occur on Guallatiri's southern flank; according to the first
Panamerican Congress on Mine Engineering and Geology, in 1942 the
volcano had about 800000 MT of sulfur ore with a grade of about 55%
sulfur. The volcano may be an important cause of arsenic pollution in
the region.
Flora, fauna and climate
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The volcano is inside the Lauca National Park and the wetlands () in
the area of Guallatiri have regional importance. Vegetation there
include 'Arenaria rivularis', 'Calandrinia compacta', 'Deyeuxia
curvula', 'Distichlis humilis', 'Lobelia oligophylla' and 'Oxychloe
andina'. Animal species include birds such as the Andean flamingo,
Andean gull, Andean goose, buff-winged cinclodes, Chilean flamingo,
condor, giant coot, James's flamingo, mountain parakeet, Puna ibis,
Puna tinamou and torrent duck. Among the mammals are the alpaca,
Altiplano chinchilla mouse, Andean swamp rat, lesser grison, llama,
mountain degu, Osgood's leaf-eared mouse, short-tailed chinchilla and
vicuña. Woodlands formed by the tree 'Polylepis tarapacana' occur on
Guallatiri; this tree forms the world's highest woodlands. The upper
parts of the mountain are covered with rocks and pioneer vegetation to
about 5500 m elevation.
The region has a tundra climate. Most precipitation falls during the
summer months, amounting to about 236 mm per year, averaged between
1997 and 2017. Moisture mainly originates in the Atlantic Ocean and
the Amazon, especially during cold events of the El Niño-Southern
Oscillation when moisture supply increases. Tree ring chronologies
from 'Polylepis tarapacana' trees growing at Guallatiri have been used
for climate reconstructions.
Eruptive history
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Volcanic activity at Guallatiri commenced either about 710,000 or
262,000-130,000 years ago and the volcano subsequently grew during the
Pleistocene and Holocene. Total magma supply at Guallatiri amounts to
0.19 -, less than at Parinacota but greater than at Lascar.
Jorquera et al. in 2019 described a two-stage growth of the volcano.
Initially, the "Guallatiri I" stage grew in the form of andesitic and
dacitic lava flows as well as heavily eroded pyroclastic deposits,
which crop out around the volcano. Then the dacitic "Guallatiri II"
developed in close proximity to the central vent; unlike the
"Guallatiri I" units it has not been eroded by glaciation and flows
still display flow structures. The central sector of the volcano is
mainly of Holocene age while the peripheral parts date to the
Pleistocene. In 2021, Sepúlveda et al. envisaged six separate stages,
rocks from the first four crop out mainly at the periphery of the
volcano and the last two in its central sector. All these units were
erupted by the central vent of Guallatiri. Some lava flows are well
preserved, while others have been glaciated.
Large eruptions similar to the 1993 eruption of Lascar may have
occurred at Guallatiri. The largest Holocene event at the volcano was
a Plinian or sub-Plinian eruption that deposited tephra and pumice
southwest of the volcano, reaching thicknesses of 1.3 m at 12 km
distance, approximately 2,600 years ago. Non-explosive eruptions also
took place, such as the Domo Tinto eruption 5,000 ± 3,000 years ago.
The eruption emplaced lobes of lava over a flat surface.
Pyroclastic flow deposits extend 10 km from Guallatiri. Radiocarbon
dating has yielded ages ranging between 6,255 ± 41 and 140 ± 30 years
Before Present. These flows are unrelated to the lava domes, which
show no evidence of collapses that could have formed pyroclastic
flows. Lahar deposits are found on the southern flanks of the volcano
and do not exceed 2 m thickness. They form when volcanic material
interacts with water, produced either by the melting of ice or through
intense rainfall. Traces of Holocene-age lahars from Guallatiri have
been found in river valleys.
Historical and seismic activity
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Guallatiri is the second-most active volcano (after Lascar) in
northern Chile. Since the 19th century, numerous small explosive
eruptions have produced thin tephra layers. The eruption history of
Guallatiri is little known and historical eruptions are poorly
documented. Eruptions with a volcanic explosivity index of 2 took
place in 1825 ± 25, 1913, July 1959, and December 1960. A further
uncertain eruption took place in 1908 and additional poorly documented
eruptions are reported from 1862, 1864, 1870, 1902, 1904, and 1987.
Radiocarbon dating has yielded evidence of at least one eruption
during the past 200 years.
Increased steam emission was observed in December 1985 and initially
attributed to Acotango volcano, before it was linked to Guallatiri; it
may have been an eruption of the latter. In May 2015, the Chilean
National Geology and Mining Service (SERNAGEOMIN) raised the volcano
alert level when seismic activity increased and a 200 m high plume
appeared over the volcano, only to lower it again in July when
activity decreased.
Shallow earthquakes and sporadic seismic swarms have been recorded at
Guallatiri; one such swarm was induced by the 2001 Peru earthquake.
Satellite imaging has not shown any evidence of ongoing deformation of
the volcanic structure.
Fumarolic activity
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Guallatiri features fumaroles and solfataras, and mud pools have also
been reported. There are two main areas, one on the western flank 50 m
below the summit and another on the south-southwestern flank.
Fumaroles form alignments, and a 400 m long fracture lies in the
southern area. Some sources also identify a third area on the upper
western flank. The vents of individual fumaroles sometimes form 6 m
wide and 3 m high cones, and there are small explosion craters
reaching widths of 5 m in the summit region. Pahoehoe-like flows up to
15 m long have been formed by liquid sulfur. Other minerals deposited
by the fumaroles are sulfates such as baryte and sulfides, including
cinnabar, antimony sulfides and arsenic sulfides.
The temperatures of the fumaroles range between 83.2 -. Guallatiri
produces gases consisting of carbon dioxide and water vapour, with
hydrogen chloride, hydrogen fluoride, hydrogen sulfide, methane and
sulfur dioxide as additional components. They appear to originate from
a hydrothermal system where intense rock-gas interaction takes place.
The water originates in part from the magma and in part from
precipitation. Different degrees of interaction with precipitation
water may explain why the south-southwestern flank fumarole gases have
a different composition than these released in the summit region. The
fumarolic activity has produced intense hydrothermal alteration of
Guallatiri's rocks east-northeast of the summit and at a lower
elevation northwest of it.
Fumarole plume
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Fumarole clouds, derived mainly from the summit fumarole, are visible
for more than 125 mi and from infrared satellite images. The fumarole
cloud influences the perception of volcanic activity by the local
population.
Puffing behaviour was noted in 1996 and emissions every half-hour in
November 1987, which gave rise to yellow-white plumes up to 1 km high.
Jet-like noises are heard from the fumaroles. According to a report by
mountaineers in 1966, fire emanated from the fumarole vents.
Hazards and monitoring
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Future eruptions may consist of the emission of lava domes or lava
flows, preceded by explosive activity that could impact the
settlements of Ancuta and Guallatiri on the southern and western
flanks. Large explosive eruptions could deposit pyroclastics over
hundreds of kilometres, with the direction depending on the wind at
the time of the eruption. Lahars would mainly impact the western and
southwestern sectors of the volcano, as the snow cover is concentrated
there. Lava flows would also primarily impact this sector of the
volcano. Pyroclastic flows may impact areas within 12 km of
Guallatiri, including the settlements Ancuta and Guallatiri. Apart
from Ancuta and Guallatiri in Chile, the volcano may threaten towns in
Bolivia and ash clouds from Guallatiri could impact airports in the
wider region as far as Paraguay. The vulnerability of the local
population reflects both widespread poverty and marginalization, and
the low population density. Significant eruptions are expected to
reoccur on century timescales.
Guallatiri is in the second category in the Chilean scale of dangerous
volcanoes and is the 30th most dangerous in the country. In 2013, the
Southern Andean Volcano Observatory began to monitor Guallatiri by
video, measurements of seismic activity and deformations of the
volcanic structure. Volcano hazard maps have been published.
Mythology and religious importance
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Guallatiri was considered to be an or , a protective mountain spirit.
The mountain was and still is worshipped by local inhabitants, and the
church in the town of Guallatiri is constructed so that it points to
the volcano. In the past, the Aymara community of Guallatire used to
celebrate rituals at the foothills of the volcano every January 1.
They regarded Guallatiri, which they called Qapurata, to be a family
consisting of a wife (the eastern María Qapurata), a husband (the
western Pedro Qapurata) and a daughter (the middle Elena Qapurata).
In the oral tradition of Chipaya, cold winds called blow from the
Pacific Ocean to the Altiplano and towards Guallatiri. The volcano
there is linked with Hell. The Chipaya believed that the waters of the
Lauca River originate on Guallatiri and come directly from hell.
See also
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* List of volcanoes in Bolivia
* List of volcanoes in Chile
License
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All content on Gopherpedia comes from Wikipedia, and is licensed under CC-BY-SA
License URL:
http://creativecommons.org/licenses/by-sa/3.0/
Original Article:
http://en.wikipedia.org/wiki/Guallatiri
