Chiqllarasu (

Quechua Quechua may refer to: *Quechua people, several indigenous ethnic groups in South America, especially in Peru *Quechuan languages, a Native South American language family spoken primarily in the Andes, derived from a common ancestral language **So ...

, ''chiqlla'' green,

Ancash Quechua Ancash Quechua, or Huaylay (Waylay), is a Quechua variety spoken in the Peruvian department of Ancash by approximately 1,000,000 people. Like Wanka Quechua, it belongs to Quechua I (according to Alfredo Torero). Classification The Ancash Quech ...

''rasu'' snow, ice, mountain with snow, Hispanicized spelling ''Chicllarazo'') Portugueza or PortuguesaThe American Alpine Journal, vol. 20, No. 2, 1976, p. 495: "... I climbed Chicllarazo (16,925 feet, 5167 meters) from here on June 17 via Patahuasi and its west ridge. This is the gray glacier-hung peak seen east from the pass which on modern maps has unnecessarily been called "Nevado Portuguesa ." is a mountain in the

Andes The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S ...

Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = Seal (emblem), National seal , national_motto = "Fi ...

, about high. It is situated in the

Ayacucho Region Ayacucho () is a department and region of Peru, located in the south-central Andes of the country. Its capital is the city of Ayacucho. The region was one of the hardest hit in the 1980s during the guerrilla war waged by Shining Path known as ...

Cangallo Province The Cangallo Province is a province located in the Ayacucho Region of Peru. It is one of the eleven that make up the region. The province has a population of 36,977 inhabitants as of census 2005. The capital of the province is the city of Cang ...

Paras District Paras District is one of six Districts of Peru, districts of the province Cangallo Province, Cangallo in Peru. Geography One of the highest mountains of the district is Chiqllarasu at . Other mountains are listed below: Ethnic groups The pe ...

. Chiqllarasu lies north-east of the mountain

Saywa Q'asa Saywa Q'asa ( Quechua '' saywa'' boundary stone, landmark, ''q'asa'' mountain pass, "landmark mountain pass", Hispanicized spelling ''Sayhuaccasa'') is a mountain in the Andes of Peru, about high. It is situated in the Ayacucho Region, Cangallo ...

, between the villages Patawasi ''(Patahuasi)'' in the northwest and Kichkawasi ''(Quichcahuasi)'' in the southeast. Chiqllarasu lies on the top of the crest of the Western Cordillera. It features a wide

caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcano eruption. When large volumes of magma are erupted over a short time, structural support for the rock above the magma chamber is ...

, known as the Cerro Sagollan caldera. Within the thick deposits

gold Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile met ...

and

silver Silver is a chemical element with the Symbol (chemistry), symbol Ag (from the Latin ', derived from the Proto-Indo-European wikt:Reconstruction:Proto-Indo-European/h₂erǵ-, ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, whi ...

have been found. These are

epithermal Hydrothermal circulation in its most general sense is the circulation of hot water (Ancient Greek ὕδωρ, ''water'',Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented throughout by Sir Henry Stuart Jones. with th ...

deposits with low

sulfide Sulfide (British English also sulphide) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. ''Sulfide'' also refers to chemical compounds lar ...

content. The caldera was formed on a central volcano which erupted

andesite Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predomi ...

and

dacite 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. ...

. This edifice originally reached a diameter of or more, and contained

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 eruptions on ...

s and short

lava flow Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or und ...

s, which are most recognizable on the eastern side of the volcano . The

Rio Apacheta Rio or Río is the Portuguese, Spanish, Italian, and Maltese word for "river". When spoken on its own, the word often means Rio de Janeiro, a major city in Brazil. Rio or Río may also refer to: Geography Brazil * Rio de Janeiro * Rio do Sul, a ...

and the Rio Quichcahuasi drain the edifice . The Atunsulla tuff is formed by many flows of

rhyolite Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained groundmass. The mineral ...

which contain

clast Clastic rocks are composed of fragments, or clasts, of pre-existing minerals and rock. A clast is a fragment of geological detritus,Essentials of Geology, 3rd Ed, Stephen Marshak, p. G-3 chunks, and smaller grains of rock broken off other rocks ...

s and

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 vol ...

. It advanced as much as along the Rio Cachi, reaching the Ayacucho basin. The river has eroded deep into the tuff, which has been removed in many places by

erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distin ...

.. Initially its volume may have been about . This volcano may be underpinned by a large

batholith A batholith () is a large mass of intrusive igneous rock (also called plutonic rock), larger than in area, that forms from cooled magma deep in Earth's crust. Batholiths are almost always made mostly of felsic or intermediate rock types, such ...

.. Samples from the pre-Atunsulla tuff volcano have been dated at 4–3.5 million years ago . The Atunsulla

tuff Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock cont ...

was erupted from Chiqllarasu around 2.4 million years ago . A long break in volcanic activity, during which the edifice was deeply eroded, may have occurred before this eruption. A

resurgent dome In geology, a resurgent dome is a dome formed by swelling or rising of a caldera floor due to movement in the magma chamber beneath it. Unlike a lava dome, a resurgent dome is not formed by the extrusion of highly viscous lava onto the surfac ...

formed 1.9 million years ago.

Hydrothermal Hydrothermal circulation in its most general sense is the circulation of hot water (Ancient Greek ὕδωρ, ''water'',Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented throughout by Sir Henry Stuart Jones. with th ...

activity occurred both before and after the eruption of the Atunsulla tuff, and the mineralization occurred 1.9 million years ago, This volcano is among the youngest in a Central Peru volcanic chain ; hot water indicate that the geothermal system may be still active .

References

* * * * {{DEFAULTSORT:Chiqllarasu Volcanoes of Peru Mountains of Ayacucho Region