Evidence for welding of a block and ash pyroclastic flow deposit: the case of Cerro Bravo Volcano, Colombia

  • 116 Accesses


Cerro Bravo is an active composite volcano located in the San Diego—Cerro Machín Volcano-Tectonic Province (SCVTP), the northernmost volcanic chain in the Colombian Andes. Among the products associated with the volcano, there is a peculiar “indurated” deposit emplaced between 7 and 2.9 ka, which resembles a block and ash pyroclastic flow deposit. Through field observations, physical property analyses, petrography and scanning electron microscopy (SEM), we demonstrate that this induration is the result of welding processes. High density, deformed glassy fragments with a common orientation, low porosity, fiamme and sintering, are the most visible characteristics. The evidence indicates that welding reached up to rank IV in a I to VI classification scheme. We suggest that welding is associated with (1) high emplacement temperature related to the syneruptive destruction of a growing endogenous dome and (2) a low glass transition temperature related to the influence of upward water diffusion after emplacement of the flow over wet ground. Thus, with emplacement temperatures between 670 and 540 °C, and water contents between 0.5 and 1.2 wt%, the welding process was unusually efficient. Calculations made indicate that for the deposit to present the observed characteristics of welding, the emplacement temperature needed to exceed the threshold of the glass transition temperature for a time of 5–6 days and have an effective viscosity of 1012 Pa s. As a result of the welding, the deposit decreased its thickness by between 15 and 7 m. This work contributes to the knowledge of welding processes and stresses the unusual occurrence of welding in this type of pyroclastic flow deposit which thus requires special emplacement conditions in terms of temperature and water content.

This is a preview of subscription content, log in to check access.

Access options

Buy single article

Instant unlimited access to the full article PDF.

US$ 39.95

Price includes VAT for USA

Subscribe to journal

Immediate online access to all issues from 2019. Subscription will auto renew annually.

US$ 199

This is the net price. Taxes to be calculated in checkout.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8


  1. Andrews GD, Russell JK, Stewart ML (2014) The history and dynamics of a welded pyroclastic dam and its failure. Bull Volcanol 76:1–16

  2. Ashwell PA, Kennedy BM, Edwards M, Cole JW (2018) Characteristics and consequences of lava dome collapse at Ruawahia, Taupo Volcanic Zone, New Zealand. Bull Volcanol 80(5):43

  3. Blanco-Quintero IF, García-Casco A, Toro LM, Moreno M, Ruiz EC, Vinasco CJ, Cardona A, Lázaro C, Morata D (2014) Late Jurassic terrane collision in the northwestern margin of Gondwana (Cajamarca Complex, eastern flank of the Central Cordillera, Colombia). Int Geol Rev 56(15):1852–1872

  4. Borrero C, Naranjo JL (1990) Casabianca Formation: a Colombian example of volcanism-induced aggradation in a fluvial basin. J Volcanol Geotherm Res 41(1-4):253–267

  5. Branney MJ, Kokelaar BP (2002) Pyroclastic density currents and the sedimentation of ignimbrites. Geological Society of London. 152 p

  6. Brook M (1984) New radiometric age data from SW, Colombia. INGEOMINAS Misión Británica, 1959.4, Bogotá. 34 p

  7. Bull KF, McPhie J (2007) Fiamme textures in volcanic successions: Flaming issues of definition and interpretation. J Volcanol Geotherm Res 164(4):205–216

  8. Calvache M, Williams SN, Young RH (1987) Distribution and volumes of deposits and dynamics of eruptions of Nevado del Ruiz and Cerro Bravo volcanoes, Colombia, over the past 2100 years (abs.). Earth & Space Science News, 67, 405 p

  9. Capra L, Macías JL, Cortés A, Dávila N, Saucedo R, Osorio-Ocampo S, Arce JL, Gavilanes-Ruiz JC, Corona-Chavez P, Garcia-Sanchez L, Sosa-Ceballos G, Vazquez R (2016) Preliminary report on the July 10–11, 2015 eruption at Volcán de Colima: pyroclastic density currents with exceptional runouts and volume. J Volcanol Geotherm Res 310:39–49

  10. Carey SN (1991) Transport and deposition of tephra by pyroclastic flows and surges. In: Fisher RV, Smith R (ed) Sedimentation in volcanic setting. SEMP Special Publication, 45, 39–59

  11. Cas RAF, Wright JV (1987) Volcanic successions: modern and ancient: a geological approach to processes, products and successions. Allen and Unwin, London 487 p

  12. Charbonnier SJ, Gertisser R (2008) Field observations and surface characteristics of pristine block-and-ash flow deposits from the 2006 eruption of Merapi Volcano, Java, Indonesia. J Volcanol Geotherm Res 177(4):971–982

  13. Charbonnier SJ, Gertisser R (2012) Evaluation of geophysical mass flow models using the 2006 block-and-ash flows of Merapi Volcano, Java, Indonesia: towards a short-term hazard assessment tool. J Volcanol Geotherm Res 231:87–108

  14. Cole PD, Calder ES, Sparks RSJ, Clarke AB, Druitt TH, Young SR, Herd RA, Harford CL, Norton GE (2002) Deposits from dome-collapse and fountain-collapse pyroclastic flows at Soufrière Hills Volcano, Montserrat. Geol Soc Lond Mem 21(1):231–262

  15. Druitt TH (1998) Pyroclastic density currents. Geol Soc Lond, Spec Publ 145(1):145–182

  16. Farquharson J, Heap MJ, Varley NR, Baud P, Reuschlé T (2015) Permeability and porosity relationships of edifice-forming andesites: a combined field and laboratory study. J Volcanol Geotherm Res 297:52–68

  17. Formenti Y, Druitt TH (2003) Vesicle connectivity in pyroclasts and implications for the fluidization of fountain-collapse pyroclastic flows, Montserrat (West Indies). Earth Planet Sci Lett 214:561–574

  18. Freundt A, Wilson CJN, Carey SN (2000) Ignimbrites and block-and-ash flows. In: Sigurdson H (ed) The Encyclopedia of Volcanoes. Academic Press, pp 581–600

  19. Gifkins CC, Allen RL, McPhie J (2005) Apparent welding textures in altered pumice-rich rocks. J Volcanol Geotherm Res 142(1):29–47

  20. Gil FC (2001) Sinopsis general sobre el volcán Cerro Bravo. Observatorio Vulcanólogico y Sismológico. Centro operativo Manizales. 17 p

  21. Giordano D, Dingwell DB, Romano C (2000) Viscosity of a Teide phonolite in the welding interval. J Volcanol Geotherm Res 103(1-4):239–245

  22. Giordano D, Nichols ARL, Dingwell DB (2005) Glass transition temperatures of natural hydrous melts: a relationship with shear viscosity and implications for the welding process. J Volcanol Geotherm Res 142:105–118

  23. Giordano D, Russell JK, Dingwell DB (2008) Viscosity of magmatic liquids: a model. Earth Planet Sci Lett 271(1-4):123–134

  24. Greene RC (1973) Petrology of the welded tuff of Devine Canyon, southeastern Oregon. Gol Surv Prof Pap 797:1–26

  25. Grunder A, Russell JK (2005) Welding processes in volcanology: insights from field, experimental, and modeling studies. J Volcanol Geotherm Res 142(1-2):1–9

  26. Grunder AL, Laporte D, Druitt TH (2005) Experimental and textural investigation of welding: effects of compaction, sintering, and vapor-phase crystallization in the rhyolitic Rattlesnake Tuff. J Volcanol Geotherm Res 142(1):89–104

  27. Guest JE, Rogers PS (1967) The sintering of glass and its relationship to welding in ignimbrites. Proc Geol Soc Lond 1641:174–177

  28. Heap MJ, Kolzenburg S, Russell JK, Campbell ME, Welles J, Farquharson JI, Ryan A (2014) Conditions and timescales for welding block-and-ash flow deposits. J Volcanol Geotherm Res 289:202–209

  29. Herd DG (1982) Glacial and volcanic geology of the Ruiz--Tolima volcanic complex, Cordillera Central, Colombia (No. 8). Instituto Nacional de Investigaciones Geológico-Mineras 53 p

  30. Hickson CJ, Russell JK, Stasiuk MV (1999) Volcanology of the 2350 BP eruption of Mount Meager volcanic complex, British Columbia, Canada: implications for hazards from eruptions in topographically complex terrain. Bull Volcanol 60(7):489–507

  31. Lescinsky DT (1990) Geology, volcanology, and petrology of Cerro Bravo, a young, dactic, stratovolcano in west-central Columbia. MSc Thesis. Lousiana State University, 244 p

  32. Ma L, Daemen JJK (2006) An experimental study on creep of welded tuff. Int J Rock Mech Min Sci 43(2):282–291

  33. Macorps E, Charbonnier SJ, Varley NR, Capra L, Atlas Z, Cabré J (2018) Stratigraphy, sedimentology and inferred flow dynamics from the July 2015 block-and-ash flow deposits at Volcán de Colima, Mexico. J Volcanol Geotherm Res 349:99–116

  34. Martínez L, Valencia R, Ceballos J, Narváez L, Pulgarín B, Correa A, Navarro S, Murcia H, Zuluaga I, Rueda G, Pardo N (2014) Geología y estratigrafía del Complejo Volcánico Nevado del Ruiz. Informe final, Bogotá – Manizales – Popayán. Colombiano, Servicio Geológico 853 pp

  35. McBirney AR (1968) Second additional theory of origin of fiamme in ignimbrites. Nature 217(5132):938

  36. McPhie J (1993) Volcanic textures: a guide to the interpretation of textures in volcanic rocks. 211 pp

  37. McPhie J, Cas R (2015) Volcanic successions associated with ore deposits: facies characteristics and ore–host relationships. In: The Encyclopedia of Volcanoes (Second Edition) (pp. 865–879)

  38. Michol KA, Russell JK, Andrews GDM (2008) Welded block and ash flow deposits from Mount Meager, British Columbia, Canada. J Volcanol Geotherm Res 169(3):121–144

  39. Miyabuchi Y (1999) Deposits associated with the 1990–1995 eruption of Unzen volcano, Japan. J Volcanol Geotherm Res 89(1-4):139–158

  40. Monsalve ML, Nuñez A (1992) El volcán Cerro Bravo Geología y Amenaza Volcánica. Rev INGEOMINAS 1:2–9

  41. Murcia HF, Borrero CA, Pardo N, Alvarado GE, Arnosio M, Scolamacchia T (2013) Depósitos volcaniclásticos: Términos y conceptos para una clasificación en español. Rev Geol Am Cent 48:15–39

  42. Peterson DW (1979) Significance of the flattening of pumice fragments in ash flow tuffs. In: Chapin CE, Elston WE (eds) Ash Flow tuffs. Geological Society of America, p 180 195

  43. Plazas JM (2010) Caracterización petrográfica y termobarométrica del Stock Tonalítico-Granodiorítico de Manizales. Trabajo de grado Universidad Nacional de Colombia Sede Bogotá, pp 1–21

  44. Quane SL, Russell JK (2005a) Ranking welding intensity in pyroclastic deposits. Bull Volcanol 67(2):129–143

  45. Quane SL, Russell JK (2005b) Welding: insights from high-temperature analogue experiments. J Volcanol Geotherm Res 142(1):67–87

  46. Quane SL, Russell JK (2006) Bulk and particle strain analysis in high-temperature deformation experiments. J Volcanol Geotherm Res 154(1-2):63–73

  47. Quane SL, Russell JK, Friedlander EA (2009) Time scales of compaction in volcanic systems. Geology 37:471–474

  48. Ragan DM, Sheridan MF (1972) Compaction of the Bishop tuff, California. Geol Soc Am Bull 83:95–106

  49. Riehle JR, Miller TF, Bailey RA (1995) Cooling, degassing and compaction of rhyolitic ash flow tuffs: a computational model. Bull Volcanol 57(5):319–336

  50. Rodríguez-Elizarrarás S, Siebe C, Komorowski JC, Espíndola JM, Saucedo R (1991) Field observations of pristine block-and ash-flow deposits emplaced April 16–17, 1991 at Volcan de Colima, Mexico. J Volcanol Geotherm Res 48(3-4):399–412

  51. Rose WI, Pearson T, Bonis S (1976) Nueé ardente eruption from the foot of a dacite lava flow, Santiaguito volcano, Guatemala. Bull Volcanol 40:23–38

  52. Ross CS, Smith RL (1961) Ash-flow tuffs: their origin, geologic relations, and identification (No. 366). United States Government Printing Office, 80 p

  53. Russell JK, Quane SL (2005) Rheology of welding: inversion of field constraints. J Volcanol Geotherm Res 142(1-2):173–191

  54. Rust A C, Russell J K (2000) Detection of welding in pyroclastic flows with ground penetrating radar: insights from field and forward modeling data. J Volcanol Geotherm Res 95(1-4):23-34

  55. Ryan AG, Russell JK, Heap MJ (2018) Rapid solid-state sintering in volcanic systems. Am Mineral 103(12):2028–2031

  56. Servicio Geológico Colombiano (SGC) 1991. Mapa preliminar de amenaza volcánica del volcán Cerro Bravo. Instituto de Investigación en Geociencias Minera y Química Regional Alto Magdalena-Ibague.147 p

  57. Simkin T, Siebert L (1994) Volcanoes of the World, 2nd edn. Geoscience Press, Tucson, p 349

  58. Smith RL (1960) Zones and zonal variations in welded ash flows. U.S. Geol Surv Prof Pap 354:149–159

  59. Sparks RSJ, Wright JV (1979) Welded air-fall tuffs. Geol Soc Am Spec Pap 180:155–166

  60. Sparks RSJ, Stasiuk MV, Gardeweg M, Swanson DA (1993) Welded breccias in andesite lavas. J Geol Soc 150:897–902

  61. Streck MJ, Grunder AL (1995) Crystallization and welding variations in a widespread ignimbrite sheet; the Rattlesnake Tuff, eastern Oregon, USA. Bull Volcanol 57(3):151–169

  62. Sulpizio R, Dellino P (2008) Sedimentology, depositional mechanisms and pulsating behaviour of pyroclastic density currents. Dev Volcanol 10:57–96

  63. Sulpizio R, Zanella E, Macías JL (2008) Deposition temperature of some PDC deposits from the 1982 eruption of El Chichón volcano (Chiapas, Mexico) inferred from rock-magnetic data. J Volcanol Geotherm Res 175(4):494–500

  64. Sulpizio R, Capra L, Sarocchi D, Saucedo R, Gavilanes-Ruiz JC, Varley NR (2010) Predicting the block-and-ash flow inundation areas at Volcán de Colima (Colima, Mexico) based on the present day (February 2010) status. J Volcanol Geotherm Res 193(1):49–66

  65. Uehara D, Cas RAF, Folkes C, Takarada S, Oda H, Porreca M (2015) Using thermal remanent magnetisation (TRM) to distinguish block and ash flow and debris flow deposits, and to estimate their emplacement temperature: 1991–1995 lava dome eruption at Mt. Unzen Volcano, Japan. J Volcanol Geotherm Res 303:92–111

  66. Ui T, Matsuwo N, Sumita M, Fujinawa A (1999) Generation of block and ash flows during the 1990–1995 eruption of Unzen Volcano, Japan. J Volcanol Geotherm Res 89(1-4):123–137

  67. Vasseur J, Wadsworth FB, Lavallée Y, Hess KU, Dingwell DB (2013) Volcanic sintering: timescales of viscous densification and strength recovery. Geophys Res Lett 40(21):5658–5664

  68. Vesga CJ, Barrero D (1978) Edades K/Ar en rocas ígneas y metamórficas de la Cordillera Central de Colombia y su implicación geológica. II Colombian Geological Congress, Bogotá

  69. Villagómez D, Spikings R (2013) Thermochronology and tectonics of the Central and Western Cordilleras of Colombia: Early Cretaceous–Tertiary evolution of the northern Andes. Lithos 160:228–249

  70. Villagómez D, Spikings R, Magna T, Kammer A, Winkler W, Beltrán A (2011) Geochronology, geochemistry and tectonic evolution of the Western and Central cordilleras of Colombia. Lithos 125(3):875–896

  71. Voight B, Davis MJ (2000) Emplacement temperatures of the November 22, 1994 nuée ardente deposits, Merapi Volcano, Java. J Volcanol Geotherm Res 100(1):371–377

  72. Voight B, Constantine EK, Siswowidjoyo S, Torley R (2000) Historical eruptions of Merapi volcano, central Java, Indonesia, 1768–1998. J Volcanol Geotherm Res 100(1):69–138

  73. Wilson CJ, Hildreth W (2003) Assembling an ignimbrite: mechanical and thermal building blocks in the Bishop Tuff, California. J Geol 111(6):653–670

  74. Woods AW, Sparks RSJ, Ritchie LJ, Batey J, Gladstone C, Bursik MI (2002) The explosive decompression of a pressurized volcanic dome: the 26 December 1997 collapse and explosion of Soufrière Hills Volcano, Montserrat. In: Druitt TH, Kokelaar BP (eds) The Eruption of Soufrière Hills Volcano, Montserrat, from 1995–1999. Geological Society of London, pp 457–465

  75. Wright HM, Cashman KV, Rosi M, Cioni R (2007) Breadcrust bombs as indicators of Vulcanian eruption dynamics at Guagua Pichincha volcano, Ecuador. Bull Volcanol 69(3):281–300

Download references


We thank the Instituto de Investigaciones en Estratigrafía (IIES) at the Universidad de Caldas for facilitating the preparation of the samples and allowing us to use their laboratories for the analyses. We also thank Luis Carlos Rosero and Fabian Aguilar Pico for their collaboration in the collection of the samples in the field. We thank Kelly Russell, an anonymous reviewer, the associate editor Judy Fierstein and the Executive editor Andrew Harris who, with their comments and suggestions, helped us greatly improve the manuscript.

Author information

Correspondence to Esteban Alarcón.

Additional information

Editorial responsibility: J. Fierstein

Electronic supplementary materials

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Alarcón, E., Murcia, H., Borrero, C. et al. Evidence for welding of a block and ash pyroclastic flow deposit: the case of Cerro Bravo Volcano, Colombia. Bull Volcanol 82, 3 (2020).

Download citation


  • Welding
  • Block and ash flow
  • Glass transition temperature
  • Flattening of glassy fragments
  • Sintering
  • Porosity