Bulletin of Volcanology

, Volume 70, Issue 6, pp 675–702 | Cite as

The rhyolitic–andesitic eruptive history of Cotopaxi volcano, Ecuador

  • Minard Hall
  • Patricia Mothes
Research Article


At Cotopaxi volcano, Ecuador, rhyolitic and andesitic bimodal magmatism has occurred periodically during the past 0.5 Ma. The sequential eruption of rhyolitic (70–75% SiO2) and andesitic (56–62% SiO2) magmas from the same volcanic vent over short time spans and without significant intermingling is characteristic of Cotopaxi’s Holocene behavior. This study documents the eruptive history of Cotopaxi volcano, presenting its stratigraphy and geologic field relations, along with the relevant mineralogical and chemical nature of the eruptive products, in order to determine the temporal and spatial relations of this bimodal alternation. Cotopaxi’s history begins with the Barrancas rhyolite series, dominated by pumiceous ash flows and regional ash falls between 0.4 and 0.5 Ma, which was followed by occasional andesitic activity, the most important being the ample andesitic lava flows (∼4.1 km3) that descended the N and NW sides of the edifice. Following a ∼400 ka long repose without silicic activity, Cotopaxi began a new eruptive phase about 13 ka ago that consisted of seven rhyolitic episodes belonging to the Holocene F and Colorado Canyon series; the onset of each episode occurred at intervals of 300–3,600 years and each produced ash flows and regional tephra falls with DRE volumes of 0.2–3.6 km3. Andesitic tephras and lavas are interbedded in the rhyolite sequence. The Colorado Canyon episode (4,500 years BP) also witnessed dome and sector collapses on Cotopaxi’s NE flank which, with associated ash flows, generated one of the largest cohesive debris flows on record, the Chillos Valley lahar. A thin pumice lapilli fall represents the final rhyolitic outburst which occurred at 2,100 years BP. The pumices of these Holocene rhyolitic eruptions are chemically similar to those of older rhyolites of the Barrancas series, with the exception of the initial eruptive products of the Colorado Canyon series whose chemistry is similar to that of the 211 ka ignimbrite of neighboring Chalupas volcano. Since the Colorado Canyon episode, andesitic magmatism has dominated Cotopaxi’s last 4,400 years, characterized by scoria bomb and lithic-rich pyroclastic flows, infrequent lava flows that reached the base of the cone, andesitic lapilli and ash falls that were carried chiefly to the W, and large debris flows. Andesitic magma emission rates are estimated at 1.65 km3 (DRE)/ka for the period from 4,200 to 2,100 years BP and 1.85 km3 (DRE)/ka for the past 2,100 years, resulting in the present large stratocone.


Alternating rhyolitic–andesitic volcanism Cotopaxi volcano Holocene history Northern Andes 



The authors kindly thank Silvana Hidalgo for helping to prepare the geologic maps, Joseph Cotten, the Institut de Recherche pour le Dévéloppement (IRD) of France, Dennis Geist, Robert Tilling, and the U.S. Geological Survey for chemical analyses of these rocks. We thank Judy Fierstein and J-C Thouret for their constructive reviews and many suggestions. Finally we thank the Instituto Geofísico of the Escuela Politécnica Nacional in Quito for their continued support.


  1. Athens JS, Ward JV (1999) The Late Quaternary of the western Amazon: climate, vegetation and humans. Antiquity 73:287–302Google Scholar
  2. Barberi F, Coltelli M, Ferrara G, Innocentii F, Navaro J, Santacroce R (1988) Plio-Quaternary volcanism in Ecuador. Geol Mag 125:1–14CrossRefGoogle Scholar
  3. Barberi F, Coltelli M, Frullani A, Rosi M, Almeida E (1995) Chronology and dispersal characterisitics of recently (last 5000 years) erupted tephra of Cotopaxi (Ecuador): implications for long-term eruptive forecasting. J Volcanol Geotherm Res 69:217–239CrossRefGoogle Scholar
  4. Beate B (1989) The Chalupas ignimbrite. In: Abstracts IAVCEI General Assembly, New Mexico. New Mexico Bur Mines Min Res Bull 131:18Google Scholar
  5. Bigazzi G, Coltelli M, Hadler J, Osorio A (1997) Provenance studies of obsidian artefacts using fission track analyses in South America: an overview. Mem 49th Cong Intern Americanistas, Quito, ARQ 14:1–16Google Scholar
  6. Clapperton C (1993) Quaternary geology and geomorphology of South America. Elsevier, AmsterdamGoogle Scholar
  7. Clapperton CM, Hall M, Mothes P, Hole M, Still J, Helmens K, Kuhry P, Gemmell A (1997) A Younger Dryas icecap in the equatorial Andes. Quat Res 47:13–28CrossRefGoogle Scholar
  8. Fierstein J, Nathenson M (1992) Another look at the calculation of fallout tephra volumes. Bull Volcanol 54:156–167CrossRefGoogle Scholar
  9. Garrison J, Davidson J, Turner S, Reid M (2003) Recycling of the Chalupas pluton at Cotopaxi volcano, NVZ, Ecuador: evidence from 238U-230Th disequilibria. Geophys Res Abst 5:11998Google Scholar
  10. Garrison J, Davidson J, Reid M, Turner S (2006) Source versus differentiation controls on U-series disequilibria: insights from Cotopaxi volcano, Ecuador. Earth Planet Sci Lett 244:548–565CrossRefGoogle Scholar
  11. Hall M (1977) El volcanismo en el Ecuador. Inst Panamericano Geog Historia, QuitoGoogle Scholar
  12. Hall M (1987) Peligros potenciales de las erupciones futuras del volcán Cotopaxi. Politécnica, Mon Geol 5(12):41–80Google Scholar
  13. Hall M, Hillebrandt von C (1988) Mapa de los peligros volcánicos potenciales asociados con el volcán Cotopaxi: (1) zona norte and (2) zona sur. Instituto Geofísico, QuitoGoogle Scholar
  14. Hall M, Beate B (1991) El volcanism Plio-Cuaternario en los Andes del Ecuador. In: Mothes P (ed) El paisaje volcánico de la Sierra ecuatoriana. Edit Nacional, Quito, Estudios Geografía 4:5–18Google Scholar
  15. Hall M, Mothes P (1997) El origen y edad de la Cangahua superior, valle de Tumbaco, Ecuador. In: Zebrowski C, Quantin P, Trujillo G (eds) Suelos volcánicos endurecidos. Mem III Symp Intern ORSTOM, Quito, pp 19–28Google Scholar
  16. Hall M, Robin C, Beate B, Mothes P, Monzier M (1999) Tungurahua volcano, Ecuador: structure, eruptive history and hazards. J Volcanol Geotherm Res 91:1–21CrossRefGoogle Scholar
  17. Hall M, Mothes P, Eissen J-P (2000) Rhyolitic magma body and ascending basic andesites: bimodal cotopaxi magmatism. Eos Trans AGU 81(48), Fall Meet Susppl, p F1309Google Scholar
  18. Hammersley L (2003) The Chalupas Caldera. PhD thesis, Univ. California, BerkeleyGoogle Scholar
  19. Humboldt A (1837–1838) Geognostische und physikalische beobachtungen uber die vulkane des hochlandes von Quito. Poggendorffs Ann Phy Chem Bd 40:161–93; Bd 44: 193–219Google Scholar
  20. Jordan E (1983) Die vergletscherung des Cotopaxi-Ecuador. Zeitschrift Gletscherkinde Glazialgeologie 19: 73–102Google Scholar
  21. La Condamine CM (1751) Diario del viaje al Ecuador. Republished 1986, Politecnica, Quito, pp 221Google Scholar
  22. Lavenu A, Noblet C, Bonhomme MG, Eguez A, Dugas F, Vivier G (1992) New K–Ar age dates of Neogene and Quaternary volcanic rocks from the Ecuadorian Andes: implications for the relationship between sedimentation, volcanism and tectonics. J S Am Earth Sci 5:309–320CrossRefGoogle Scholar
  23. Miller CD, Mullineaux D, Hall M (1978) Reconnaissance map of potential volcanic hazards from Cotopaxi volcano, Ecuador. US Geol Surv Misc Invest Series Map I-1702Google Scholar
  24. Mothes P (1992) Lahars of Cotopaxi volcano, Ecuador: hazard and risk evaluation. In: McCall GJH, Laming DJC, Scott SC (eds). Geohazards, natural and man-made. Chapman and Hall, London, pp 53–64Google Scholar
  25. Mothes P, Hall M, Janda R (1998) The enormous Chillos valley lahar: an ash-flow generated debris flow from Cotopaxi volcano, Ecuador. Bull Volcanol 59:233–244CrossRefGoogle Scholar
  26. Mothes P, Hall M, Andrade D, Samaniego P, Pierson T, Ruiz G, Yepes H (2004) Character, stratigraphy and magnitude of historical lahars of Cotopaxi volcano, Ecuador. Acta Volcanol 16:85–107Google Scholar
  27. Reiss W (1874) Uber lavastrome der Tungurahua und Cotopaxi. Zeitschr Dt Geol Ges 26:907–927Google Scholar
  28. Reiss W, Stübel A (1869–1902) Das hochgebirge der republik Ecuador II: petrographische untersuchungen: ostkordillere: BerlinGoogle Scholar
  29. Siebert L (1984) Large volcanic debris avalanches—characteristics of source areas, deposits, and associated eruptions. J Volcanol Geothermal Res 22:163–197CrossRefGoogle Scholar
  30. Smyth M (1991) Movement and emplacement mechanisms of the Río Pita volcanic debris avalanche and its role in the evolution of Cotopaxi volcano. PhD thesis, Univ Aberdeen, ScotlandGoogle Scholar
  31. Smyth M, Clapperton C (1986) Late Quaternary volcanic debris avalanche at Cotopaxi, Ecuador. Revista CIAF, Bogota 11:24–38Google Scholar
  32. Sodiro L (1877) Relacion sobre la erupcion del Cotopaxi acaecida del dia 26 de junio, 1877. Imprenta Nacional Quito, pp 40Google Scholar
  33. Stübel A (1897) Die vulkanberge Ecuadors. LeipzigGoogle Scholar
  34. Wolf T (1878) Memoria sobre el Cotopaxi y su última erupción acaecida el 26 de junio de 1877. Imprenta, El Comercio, Guayaquil, pp 48Google Scholar
  35. Wolf T (1904) Crónica de los fenómenos volcánicos y terremotos en el Ecuador. Imprenta, Univ Central, Quito, pp 167Google Scholar

Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  1. 1.Instituto GeofísicoEscuela Politécnica NacionalQuitoEcuador

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