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Cordón_de_Puntas_Negras Latitude and Longitude:
23°44′34″S 67°32′03″W / 23.74278°S 67.53417°W / -23.74278; -67.53417
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Cordón de Puntas Negras
Cordón de Puntas Negras seen from Laguna Miscanti with Cerro Miscanti in the foreground (left).
Highest point
Elevation5,852 m (19,199 ft) [1]
Coordinates 23°44′34″S 67°32′03″W / 23.74278°S 67.53417°W / -23.74278; -67.53417
Geography
Location Chile
Parent range Andes
Geology
Mountain type Stratovolcanoes
Last eruptionUnknown

Cordón de Puntas Negras is a 500 km2 (193 sq mi) volcanic chain located east of the Salar de Atacama in Chile's Antofagasta Region.

Cordón de Puntas Negras is constructed along the major Calama–Olacapato–El Toro fault [2]: 213  and is 70 kilometres (43 mi) long. [3] The 25 kilometres (16 mi) long volcanic chain intersects with the 13 kilometres (8.1 mi) long Cordón Chalviri volcanic chain. [4] Both chains cover a surface area of 500 square kilometres (190 sq mi) and contain cones, vents, lava domes, lava flows and maars, [5] including a lava dome and silicic flow with a surface area of 13 square kilometres (5.0 sq mi). [1] Puntas Negras specifically covers an area of 400 square kilometres (150 sq mi) [6] and is the highest summit in the chain and features a 500 metres (1,600 ft) wide crater and a 13 kilometres (8.1 mi) long pyroclastic flow. [4] Puntas Negras runs from the Chiliques volcano on the north to volcán Puntas Negras (5,852 m (19,199 ft)) almost to the SE. The Puntas Negras Volcano forms the common endpoint of two chains of volcanoes in a V-shaped configuration. The southern leg of the V is called "Cordón Chalviri" whose other extreme is the Cerro Tuyajto, SW of Puntas Negras and at the same distance SE of the Miñiques volcano. Several small volcanic centres and lava flows are found here, including Aguas Calientes, Cerros Cenizas, Chinchilla and Laguna Escondida which have well preserved craters. [1] The volcanic chain is associated with a topographic anomaly in the region, a property that other volcanoes in the area also have. [7]

Rocks in the chain are andesite, basaltic andesite and dacite [1] containing biotite, hornblende and pyroxene. [4] Magmas from this volcanic chain have a calc-alkaline composition formed by partial melting of a mantle wedge, [2]: 218, 225  with research indicating a decrease in SiO2 concentration over time. [8] In the Tuyajto group, past fumarolic activity has bleached the volcanic rocks in the summit region. [8]

The basement beneath the chain is composed from Ordovician marine sediments that were later deformed by the Acadian orogeny. [9] The 35 by 70 kilometres (22 mi × 43 mi) La Pacana caldera is buried beneath Puntas Negras. [1] Both the 3.2 ± 0.3 Patao ignimbrite [10] and the 2.4 ± 0.4 mya Pampa Chamaca or Tuyajto ignimbrite from La Pacana may have been erupted from beneath Puntas Negras. [11] [12] the Tuyajto ignimbrite is 530,000 ± 170,000 years old. [13]

Biotites in andesitic lavas have been dated 0.7 ± 0.3 to 0.3 ± 0.2 million years ago. [14] Volcan Puntas Negras has generated postglacial lava flows [3] and a 13 square kilometres (5.0 sq mi) large lava dome west of Puntas Negras may be of Holocene age. [4] An olivine basalt flow from the northern part of the chain extends over 10 kilometres (6.2 mi) towards Salar el Laco and may be of late Holocene age. [8] The youngest volcanic centre appears to be located southeast of Laguna Escondida. [1] Historical eruptions may have occurred in the Chalviri chain. [4] A zone of anomalous electrical conductivity down to depths of 6 kilometres (3.7 mi) extends north to Lascar volcano. [15] Cerro Overo at the southeastern end of Puntas Negras has been undergoing active deformation, [3]: 1369  with a previously observed pattern of subsidence before 2003–2005 switching to a pattern of inflation. Filling and emptying of a magma reservoir linked to Puntas Negras may be the cause for these deformation patterns. [3] Future eruptions may threaten mining operations at El Laco and International Route CH-23 [ es]. [4]

The volcanic chain forms a water divide in the Andes, separating the Puna de Atacama from the basins Laguna Miscanti and Laguna Miniques. [16]: 176  A catchment area of 320 square kilometres (120 sq mi) for the Laguna Miscanti lies in the Cordón de Puntas Negras. [17] Puntas Negras has been affected by glaciation during the Pleistocene, [18] with moraines reaching up to 4,400 metres (14,400 ft) altitude. Possibly, the entire chain was covered with glaciers, [6] and certainly the southern part where several sets of moraines and glacial trimlines have been identified. [19] Water from Cordón de Puntas Negras is a principal water source for Laguna Miscanti. [20]

See also

References

  1. ^ a b c d e f "Cordon de Puntas Negras". Global Volcanism Program. Smithsonian Institution. 24 February 2016.
  2. ^ a b Matteini, M.; Mazzuoli, R.; Omarini, R.; Cas, R.; Maas, R. (February 2002). "The geochemical variations of the upper cenozoic volcanism along the Calama–Olacapato–El Toro transversal fault system in central Andes (~24°S): petrogenetic and geodynamic implications". Tectonophysics. 345 (1–4): 211–227. Bibcode: 2002Tectp.345..211M. doi: 10.1016/S0040-1951(01)00214-1.
  3. ^ a b c d Henderson, S. T.; Pritchard, M. E. (May 2013). "Decadal volcanic deformation in the Central Andes Volcanic Zone revealed by InSAR time series". Geochemistry, Geophysics, Geosystems. 14 (5): 1358–1374. Bibcode: 2013GGG....14.1358H. doi: 10.1002/ggge.20074.
  4. ^ a b c d e f 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. 19. ISSN  0717-7305. Archived from the original (PDF) on June 29, 2021. Retrieved 20 August 2021.
  5. ^ Cabrol, Nathalie A.; Grin, Edmond A.; Chong, Guillermo; Minkley, Edwin; Hock, Andrew N.; Yu, Youngseob; Bebout, Leslie; Fleming, Erich; Häder, Donat P.; Demergasso, Cecilia; Gibson, John; Escudero, Lorena; Dorador, Cristina; Lim, Darlene; Woosley, Clayton; Morris, Robert L.; Tambley, Cristian; Gaete, Victor; Galvez, Matthieu E.; Smith, Eric; Uskin-Peate, Ingrid; Salazar, Carlos; Dawidowicz, G.; Majerowicz, J. (June 2009). "The High-Lakes Project". Journal of Geophysical Research: Biogeosciences. 114 (G2): n/a. Bibcode: 2009JGRG..114.0D06C. doi: 10.1029/2008JG000818.
  6. ^ a b Schröder, Hilmar (September 2001). "Kommentar zu den Anmerkungen von Bettina Jenny, Klaus Kammer und Bruno Messerli". Erdkunde (in German). 55 (3): 288–289. doi: 10.3112/erdkunde.2001.03.07. JSTOR  25647397.
  7. ^ Perkins, Jonathan P.; Finnegan, Noah J.; Henderson, Scott T.; Rittenour, Tammy M. (2016-08-01). "Topographic constraints on magma accumulation below the actively uplifting Uturuncu and Lazufre volcanic centers in the Central Andes". Geosphere. 12 (4): 1078–1096. Bibcode: 2016Geosp..12.1078P. doi: 10.1130/GES01278.1. ISSN  1553-040X.
  8. ^ a b c Zeil, Werner (December 1964). "Die Verbreitung des jungen Vulkanismus in der Hochkordillere Nordchiles". Geologische Rundschau (in German). 53 (2): 752–753. Bibcode: 1964GeoRu..53..731Z. doi: 10.1007/BF02054561. S2CID  128979648.
  9. ^ Frutos, J.; Oyarzun, J.; Shiga, Y.; Alfaro, G. (1990). "The el Laco Magnetite Lava Flow Deposits, Northern Chile: An Up-To-Date Review and New Data". Stratabound Ore Deposits in the Andes. Berlin, Heidelberg: Springer Berlin Heidelberg. p. 681. doi: 10.1007/978-3-642-88282-1_54. ISBN  978-3-642-88282-1.
  10. ^ Coira, B.; Kay, S. Mahlburg; Viramonte, J. (1993-08-01). "Upper Cenozoic Magmatic Evolution of the Argentine Puna—a Model for Changing Subduction Geometry". International Geology Review. 35 (8): 702. Bibcode: 1993IGRv...35..677C. doi: 10.1080/00206819309465552. ISSN  0020-6814.
  11. ^ de Silva, Shanaka L.; Gosnold, William D. (November 2007). "Episodic construction of batholiths: Insights from the spatiotemporal development of an ignimbrite flare-up". Journal of Volcanology and Geothermal Research. 167 (1–4): 325. Bibcode: 2007JVGR..167..320D. doi: 10.1016/j.jvolgeores.2007.07.015.
  12. ^ Gardeweg, Moyra; Ramirez, Carlos F. (June 1987). "La Pacana caldera and the Atana Ignimbrite ? a major ash-flow and resurgent caldera complex in the Andes of northern Chile". Bulletin of Volcanology. 49 (3): 563. Bibcode: 1987BVol...49..547G. doi: 10.1007/BF01080449. S2CID  129372984.
  13. ^ Kern, Jamie M.; de Silva, Shanaka L.; Schmitt, Axel K.; Kaiser, Jason F.; Iriarte, A. Rodrigo; Economos, Rita (27 May 2016). "Geochronological imaging of an episodically constructed subvolcanic batholith: U-Pb in zircon chronochemistry of the Altiplano-Puna Volcanic Complex of the Central Andes". Geosphere. 12 (4): 1059. Bibcode: 2016Geosp..12.1054K. doi: 10.1130/GES01258.1. ISSN  1553-040X.
  14. ^ Naranjo, J.A.; Henríquez, F. "Geocronología K-Ar y antecedentes paleoambientales del volcanismo de óxido de fierro de El Laco". researchgate.net (in Spanish). XII Congreso Geológico Chileno. Retrieved 24 February 2016.
  15. ^ Díaz, Daniel; Brasse, Heinrich; Ticona, Faustino (March 2012). "Conductivity distribution beneath Lascar volcano (Northern Chile) and the Puna, inferred from magnetotelluric data". Journal of Volcanology and Geothermal Research. 217–218: 27. Bibcode: 2012JVGR..217...21D. doi: 10.1016/j.jvolgeores.2011.12.007.
  16. ^ Niemeyer, Hans F. Hoyas Hydrograficas de Chile: Segunda region (PDF). Archived from the original (PDF) on 21 July 2018. Retrieved 19 September 2019.
  17. ^ Valero-Garcés, Blas L.; Grosjean, Martin; Kelts, Kerry; Schreier, Hans; Messerli, Bruno (July 1999). "Holocene lacustrine deposition in the Atacama Altiplano: facies models, climate and tectonic forcing". Palaeogeography, Palaeoclimatology, Palaeoecology. 151 (1–3): 105. Bibcode: 1999PPP...151..101V. doi: 10.1016/S0031-0182(99)00018-8.
  18. ^ Naranjo, Jose A.; Henrquez, Fernando; Nystrom, Jan O. (19 January 2010). "Metasomatismo de contacto subvolcanico en el Complejo Volcanico El Laco". Andean Geology. 37 (1): 111. doi: 10.5027/andgeoV37n1-a05.
  19. ^ THORNTON, Rachel M. (2017). GLACIAL HISTORY OF S CORDON DE PUNTAS NEGRAS, CHILE 24.3°S USING IN SITU COSMOGENIC 36CL. Joint 52nd Northeastern Annual Section / 51st North-Central Annual Section Meeting. Retrieved 2019-11-27.
  20. ^ Valero-Garcés, Blas L.; Grosjean, Martin; Schwalb, Antje; Geyh, Mebus; Messerli, Bruno; Kelts, Kerry (1996-07-01). "Limnogeology of Laguna Miscanti: evidence for mid to late Holocene moisture changes in the Atacama Altiplano (Northern Chile)". Journal of Paleolimnology. 16 (1): 4. Bibcode: 1996JPall..16....1V. doi: 10.1007/BF00173268. ISSN  0921-2728. S2CID  128636498.
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