Acamarachi

Acamarachi
Acamarachi
Pili
	Acamarachi viewed from the north
Highest point
Elevation	6,046 m (19,836 ft)
Prominence	1,608 m (5,276 ft)
Parent peak	San Pedro (Chile volcano)
Listing	Ultra
Coordinates	23°18′S 67°37′W / 23.300°S 67.617°W
Geography
	Acamarachi Antofagasta Region, Chile Acamarachi Acamarachi (Chile) Acamarachi Acamarachi (Argentina)
Parent range	Andes
Geology
Mountain type	Stratovolcano
Last eruption	Unknown
Climbing
First ascent	14 March 1939 - Aldo Bonacossa and Remigio Gerard (Italy)

Acamarachi (also known as Pili^[1]) is a 6,046-metre (19,836 ft) high volcano in northern Chile.^[5] In this part of Chile, it is the highest volcano.^[2] Its name means "black moon".^[6] It is a volcano in the Central Volcanic Zone of the Andes, a zone of strong volcanic activity during the last million years. Old volcanoes in the area are well-preserved, due to the dry climate.

Acamarachi itself is a cone-shaped volcano with steep upper flanks and a lava dome on its northern side. While there is no indication of historical activity and the flank lava flows are old, some lava flows around the summit crater and a lava coulee north of Acamarachi on the saddle between Acamarachi and Colachi volcano may be postglacial in age. Acamarachi is formed by andesitic and dacitic rocks.

Acamarachi features an Inca mountain sanctuary on which several figurines have been found. One female figurine is made out of silver, a male one is made out of thorny oyster. Both of these figurines were found with miniature clothing.

Geological context

The volcano is located in the Central Volcanic Zone, an area of volcanism in the Andes. Volcanism in this area is dependent on the subduction in the Peru-Chile Trench. 27 million years ago, in this area of the Andes large rhyolitic eruptions commenced and formed major ignimbrites, dramatically increasing 10 million years ago. At the same time starting in the Miocene, andesitic to dacitic eruptive activity has formed large stratovolcanoes. This activity in the late Pleistocene and Holocene has created the current volcanic arc.^[7]

The climate of the area is hyperarid. Thus, ignimbrites and individual volcanoes keep most of their original appearance. Most of these volcanoes are remote structures that are unlikely to affect significant population, although wind-driven transport of tephra can potentially cause economic and other damage at considerable distance.^[7]

Geology

Acamarachi is a 6,046 metres (19,836 ft) high^[2]^[a]^[b] steep-sided conical volcano, like several other volcanoes in the region. Such a shape is due to the relatively high viscosity of the lavas forming them. In the case of Acamarachi, the upper slopes reach a slope angle of 45°. On the volcano's northern flank there is a large lava dome^[2] while the rest of the edifice is symmetrical.^[14] A 10–15 metres (33–49 ft) deep crater lake lies in the summit crater and may be kept ice-free by magmatic heat.^[15] As of 2021^[update], it is considered the world's highest site of an underwater dive.^[16]

Acamarachi is constructed by andesite and dacite.^[17] Rocks are porphyritic and contain hornblende as well as biotite or pyroxene. Augite, hypersthene and plagioclase are also present, with smaller contents of olivine and quartz.^[14] The composition of Acamarachi's rocks resembles that of Colachi's.^[15]

A study of lava flows at the summit concluded that Acamarachi's last eruption may have occurred during the Holocene.^[5]^[2] There are no young lava flows on the flanks and the summit crater is degraded. Possibly after the ice ages, north of Acamarachi a silicic coulee was erupted on the saddle between Acamarachi and Colachi. This coulee has well preserved flow structures and covers 7 kilometres (4.3 mi). No evidence exists for activity in historical times^[14] and the lack of volcanic damage to archeological sites suggests that it was active during the last millennium. Renewed activity would most likely generate lava flows or lava domes; impact would be limited on the immediate surroundings of the volcano.^[15]

The volcano is part of a northwest-bound alignment along with Rili, Colachi and Yalquis-Putas, which may be linked to faults underground.^[18] However, Colachi and Acamarachi seem to have separate magmatic systems. They are both relatively low over the surrounding terrain which is about 4,800 metres (15,700 ft) high and is formed by raised ignimbrites.^[14]

Acamarachi does not have glaciers or any perennial ice structures. Such lack of glaciation is also observed on other mountains in the neighbourhood such as Aucanquilcha and is probably due to the arid climate.^[19] In the past however the mountain was probably extensively glaciated, with glacier lobes forming at its foot and cirques developing around the summit. Terminal moraines lie in the Quebrada Ojos de Hécar and Quebrada Acamarachi, with several individual moraines between 4,500–5,000 metres (14,800–16,400 ft) elevation.^[20]

Archeology

Acamarachi is known as an Inca mountain sanctuary, among at a minimum 15 other mountain sanctuaries known to have been used by the Inca. Other known sanctuaries are Cerro Colorado, Cerro Lailay, Cerro del Leon, Cerro Mullay, Cerro Toco, Cerro Quimal, Curiquinca, Juriques, Laguna Verde, Licancabur, Linzor, Paniri, Sairecabur, Tatio and Toconce.^[21] On its summit, four different ceremonial platforms are arranged in a cloverleaf conformation.^[22]

Inca figurines representing individuals of various sexes have been found on Acamarachi.^[22] The figurines found at Acamarachi may represent mid-level imperial officials, considering the simple tunics they wore.^[22]^[23] One figurine made out of Spondylus shell wore miniature clothing made out of camelid wool, the clothing having an imperial design with multicoloured decorations.^[24] The tunic itself is yellow.^[25] The textiles found on Acamarachi belong to a style known as "Catarpe", which is associated with Inca presence.^[26] Such clothing seems to be miniaturized versions of Inca clothing.^[27] This figurine has no plaque, unlike some other Inca figurines.^[28] A feather and a shawl are other accessories that have been found on the figurine.^[29] The function of such figurines is unknown, several theories have been proposed, such as representing deities.^[30] Another figurine representing a woman was also found there in 1971, in red miniature clothing with decorations too, as well as a red feather.^[22] This figure is made out of silver.^[31] Such dressed figurines have been found on other Andean summits, such as Aconcagua, Cerro El Plomo, Cerro Mercedario, Cerro Las Tortolas, Cerro Gallan, Copiapo and Pichu Pichu.^[32] Acamarachi's figurines are now exposed in the R. P. Gustavo Le Paige Archaeological Museum of San Pedro de Atacama.^[27]

The region in which Acamarachi is located was a southern part of the Inca Empire.^[23] A major Inca road passed by the town of Toconao, not far from Acamarachi.^[33]

Notes

^ Other data from digital elevation models: SRTM yields 6,024 metres (19,764 ft),^[8] ASTER 5,971 metres (19,590 ft),^[9] SRTM filled with ASTER6,024 metres (19,764 ft),^[9] ALOS 5,971 metres (19,590 ft)^[10] and TanDEM-X 6,050 metres (19,850 ft).^[11]
^ The height of the nearest key col is 4,438 metres (14,560 ft),^[12] leading to a topographic prominence of 1,608 metres (5,276 ft) with a topographical dominance of 26.6%. Its parent peak is San Pedro and the Topographic isolation is 175.3 kilometres (108.9 mi).^[13]

References

^ ^a ^b "Acamarachi". Global Volcanism Program. Smithsonian Institution., Synonyms & Subfeatures
^ ^a ^b ^c ^d ^e ^f ^g "Acamarachi". Global Volcanism Program. Smithsonian Institution.
^ Pietro Meciani. Le Ande.
^ Evelio Echevarría (1963). "AAJ". AAJ.
^ ^a ^b Lee Siebert; Tom Simkin; Paul Kimberly (9 February 2011). Volcanoes of the World: Third Edition. University of California Press. p. 188. ISBN 978-0-520-94793-1.
^ Roberto Lehnert Santander (2000). Mitos y creencias del mundo atacameño (in Spanish). Universidad de Antofagasta, Instituto de Investigaciones Antropológicas. p. 150. ISBN 9789567143498.
^ ^a ^b Teresa Moreno (Ph. D.); Wes Gibbons (2007). The Geology of Chile. Geological Society of London. p. 150. ISBN 978-1-86239-220-5.
^ USGS, EROS Archive. "USGS EROS Archive - Digital Elevation - SRTM Coverage Maps". Retrieved 12 April 2020.
^ ^a ^b "ASTER GDEM Project". ssl.jspacesystems.or.jp. Retrieved 14 April 2020.
^ "ALOS GDEM Project". Retrieved 14 April 2020.
^ TanDEM-X, TerraSAR-X. "Copernicus Space Component Data Access". Archived from the original on 12 April 2020. Retrieved 12 April 2020.
^ "Andean Mountains - All above 5000m". Andes Specialists. Retrieved 12 April 2020.
^ "Pili / Acamarachi". Andes Specialists. Retrieved 12 April 2020.
^ ^a ^b ^c ^d "Colachi & Acamarachi". volcano.oregonstate.edu. Oregon State University. Retrieved 4 August 2016.
^ ^a ^b ^c Amigo, Álvaro R.; Bertin, Daniel U.; Orozco, Gabriel L. (2012). Peligros volcánicos de la Zona Norte de Chile (PDF) (Report). Carta geológica de Chile: Serie Geología Ambiental (in Spanish). Vol. 17. SERVICIO NACIONAL DE GEOLOGÍA Y MINERÍA. p. 17. ISSN 0717-7305. Archived from the original (PDF) on June 29, 2021. Retrieved 20 August 2021.
^ Robins, Marc; Murphy-Lavoie, Heather M. (2022). "Diving At Altitude". StatPearls. StatPearls Publishing. PMID 29630202.
^ Chalmers Moyes Clapperton (1993). Quaternary Geology and Geomorphology of South America. Elsevier. p. 126. ISBN 978-0-444-88247-9.
^ Zeil, Werner (December 1964). "Die Verbreitung des jungen Vulkanismus in der Hochkordillere Nordchiles". Geologische Rundschau (in German). 53 (2): 750. Bibcode:1964GeoRu..53..731Z. doi:10.1007/BF02054561. S2CID 128979648.
^ Kull, Christoph; Grosjean, Martin (1 December 2000). "Late Pleistocene climate conditions in the north Chilean Andes drawn from a climate–glacier model". Journal of Glaciology. 46 (155): 627. Bibcode:2000JGlac..46..622K. doi:10.3189/172756500781832611.
^ Jenny, Bettina; Kammer, Klaus (1996). Climate Change in den trockenen Anden (in German). Verlag des Geographischen Institutes der Universität Bern. p. 59. ISBN 3906151034.
^ Besom 2013, pp. 11–12
^ ^a ^b ^c ^d Le Paige, Gustavo (1978). "Vestigios arqueológicos incaicos en las cumbres de la zona atacameña" (PDF). Estudios Atacameños (in Spanish) (6): 40. Archived from the original (PDF) on 13 August 2016. Retrieved 4 August 2016.
^ ^a ^b Besom 2013, p. 193
^ Besom 2013, p. 134
^ Dransart 1995, p. 9
^ Agüero 2000, p. 10
^ ^a ^b Agüero 2000, p. 21
^ Besom 2013, p. 197
^ Dransart 1995, p. 6
^ Besom 2013, p. 135
^ Dransart 1995, p. 47
^ Dransart 1995, p. 5
^ Varela, Varinia (1999). "El Camino del Inca en la cuenca superior del río Loa, desierto de Atacama, norte de Chile". Estudios Atacameños (in Spanish) (18): 89–106. doi:10.22199/S07181043.1999.0018.00008. ISSN 0718-1043. Retrieved 4 August 2016.

Sources

Agüero, Carolina P. (2000). "Fragmentos para armar un territorio. La textiler í a en Atacama durante los per í odos Intermedio Tardío y Tardío" (PDF). Estudios Atacameños (in Spanish) (20): 7–28. doi:10.22199/S07181043.2000.0020.00002. Archived from the original (PDF) on 13 August 2016. Retrieved 4 August 2016.
Thomas Besom (15 April 2013). Inka Human Sacrifice and Mountain Worship: Strategies for Empire Unification. UNM Press. ISBN 978-0-8263-5308-5.
Penny Dransart (1995). Elemental Meanings: Symbolic Expression in Inka Miniature Figurines (PDF). Institute of Latin American Studies. ISBN 978-1-900039-00-0.