Bulletin of Volcanology

, Volume 72, Issue 4, pp 449–467 | Cite as

Explosive lava–water interactions I: architecture and emplacement chronology of volcanic rootless cone groups in the 1783–1784 Laki lava flow, Iceland

  • Christopher W. HamiltonEmail author
  • Thorvaldur Thordarson
  • Sarah A. Fagents
Research Article


To determine the relationships between rootless cone emplacement mechanisms, morphology, and spatial distribution, we mapped the Hnúta and Hrossatungur groups of the 1783–1784 Laki lava flow in Iceland. We based our facies maps on Differential Global Positioning System (DGPS) measurements, photogeological interpretations, and supporting field observations. The study area covers 2.77 km2 and includes 2216 explosion sites. To establish the timing of rootless cone formation we incorporated tephrochronological constraints from eighty-eight stratigraphic sections and determined that the Hnúta and Hrossatungur groups are composite structures formed by the emplacement of six geographically and chronologically discrete domains. Rootless eruptions initiated in domain 1 on the first day of the Laki eruption (June 8, 1783) and lasted 1–2 days. The second episode of rootless activity began in domain 2 on June 11 and lasted 1–3 days. The four domains of the Hrossatungur group dominantly formed after June 14 and exhibit a complex emplacement sequence that reflects interactions between the Laki lava, contemporaneously emplaced rootless cones, and an existing topographic ridge. In the study area, we identify three distinct rootless cone archetypes (i.e., recurring morphological forms) that are related to tube-, channel-, and broad sheet lobe-fed eruptions. We assert that emplacement of lava above compressible substrates (e.g., unconsolidated sediments) may trigger rootless eruptions by causing subsidence-induced flexure and failure of the basal crust, thereby allowing molten lava (fuel) to come into direct contact with groundwater (coolant) and initiating analogs to explosive molten fuel–coolant interactions (MFCIs).


Volcanic rootless cones Pseudocraters Phreatomagmatic Explosive lava–water interactions Laki Iceland Mars 



We thank Karen Pascal for her assistance in the field; Benjamin Brooks and the Pacific GPS facility for providing DGPS survey equipment and post-processing resources; Bruce Houghton and Scott Rowland for their help during the preparation of this manuscript; Bernd Zimanowski and an anonymous reviewer for their encouraging comments and suggestions; and financial support from the National Aeronautics and Space Administration (NASA) Mars Fundamental Research Program (MFRP) grant NNG05GM08G, NASA Mars Data Analysis Program (MDAP) grant NNG05GQ39G, Geological Society of America (GSA), and Icelandic Centre for Research (RANNÍS). SOEST publication number 7807. HIGP publication number 1801.

Supplementary material

445_2009_330_MOESM1_ESM.pdf (802 kb)
Appendix 1 (PDF 801 kb)


  1. Allen CC (1979) Volcano-ice interactions on Mars. J Geophys Res 84:8048–8059CrossRefGoogle Scholar
  2. Brigham WT (1868) The eruption of Hawaiian volcanoes. Boston Soc Natl Mem 1:564–587Google Scholar
  3. Calvari S, Pinkerton H (1999) Lava tube morphology on Etna and evidence for lava flow emplacement mechanisms. J Volcanol Geotherm Res 90:263–280CrossRefGoogle Scholar
  4. Colgate SA, Sigurgeirsson T (1973) Dynamic mixing of water and lava. Nature 244:552–555CrossRefGoogle Scholar
  5. Fagents SA, Lanagan P, Greeley R (2002) Rootless cones on Mars: a consequence of lava-ground ice interaction. In: Smellie JL, Chapman MG (eds) Volcano-ice interaction on Earth and Mars. Geol Soc Spec Publ 202:295–317Google Scholar
  6. Fagents SA, Thordarson T (2007) Rootless volcanic cones in Iceland and on Mars. In: Chapman MG (ed) The geology of Mars: evidence from Earth-based analogs. Cambridge University Press, New York, pp 151–177CrossRefGoogle Scholar
  7. Fisher RV (1968) Pu’u Hou littoral cones, Hawaii. Geol Rundsch 57:837–864CrossRefGoogle Scholar
  8. Fisher RV, Schmincke H-U (1984) Pyroclastic rocks. Springer-Verlag, New YorkGoogle Scholar
  9. Frey H, Lowry BL, Chase SA (1979) Pseudocraters on Mars. J Geophys Res 84:8075–8086CrossRefGoogle Scholar
  10. Frey H, Jarosewich M (1982) Subkilometer Martian volcanoes: properties and possible terrestrial analogs. J Geophys Res 87:9867–9879CrossRefGoogle Scholar
  11. Greeley R, Fagents SA (2001) Icelandic pseudocraters as analogs to some volcanic cones on Mars. J Geophys Res 106:20527–20546CrossRefGoogle Scholar
  12. Guest JE, Wood C, Greeley R (1984) Lava tubes, terraces and megatumuli on the 1614–24 pahoehoe lava flow field, Mount Etna, Sicily. Bull Volcanol 47:635–648CrossRefGoogle Scholar
  13. Guilbaud MN, Self S, Thordarson T, Blake S (2005) Morphology, surface structures, and emplacement of lavas produced by Laki, A.D. 1783–1784. Geol Soc Am Spec Pap 396:81–102Google Scholar
  14. Hamilton CW, Fagents SA, Thordarson T (2010) Explosive lava–water interactions II: self-organization processes among volcanic rootless eruption sites in the 1783–1784 Laki lava flow, Iceland. Bull Volcanol. doi: 10.1007/s00445-009-0331-5
  15. Harris JL, Favalli M, Mazzarini F, Hamilton CW (2009) Construction dynamics of a lava channel. Bull Volcanol 71:459–474. doi: 10.1007/s00445-008-0238-6 CrossRefGoogle Scholar
  16. Hon K, Kauahikaua J, Denlinger R, MacKay R (1994) Emplacement and inflation of pahehoe sheet flows: observations and measurements of active lava flows on Kilauea Volcano, Hawaii. Geol Soc Am Bull 106:351–370CrossRefGoogle Scholar
  17. Jurado-Chichay Z, Rowland SK, Walker GPL (1996) The formation of circular littoral cones from tube-fed pahoehoe: Mauna Loa, Hawaii. Bull Volcanol 57:471–482Google Scholar
  18. Kauahikaua J, Cashman KV, Mattox TN, Heliker CC, Hon KA, Mangan MT, Thornber CR (1998) Observations on basaltic lava streams in tubes from Kilauea Volcano, island of Hawai‘i. J Geophys Res 103:27303–27323CrossRefGoogle Scholar
  19. Keszthelyi L, Thordarson T, McEwen A, Haack H, Guilbaud M-N, Self S, Rossi MJ (2004) Icelandic analogs to Martian flood lavas. Geochem Geophys Geosyst 5:Q11014. doi: 10.1029/2004GC000758 CrossRefGoogle Scholar
  20. Lanagan PD, McEwen AS, Keszthelyi LP, Thordarson T (2001) Rootless cones on Mars indicating the presence of shallow equatorial ground ice in recent times. Geophys Res Lett 28:2365–2367CrossRefGoogle Scholar
  21. Mattox TN, Mangan MT (1997) Littoral hydrovolcanic explosions: a case study of lava-seawater interaction at Kilauea volcano. J Volcanol Geotherm Res 75:1–17CrossRefGoogle Scholar
  22. Mattox TN, Heliker C, Kauahikaua J, Hon K (1993) Development of the 1990 Kalapana flow field, Kilauea Volcano, Hawai‘i. Bull Volcanol 55:407–413CrossRefGoogle Scholar
  23. Mellon MT, Jakosky BM (1995) The distribution and behavior of martian ground ice during past and present epochs. J Geophys Res 100:11781–11799CrossRefGoogle Scholar
  24. Morrissey M, Zimanowski B, Wohletz K, Buettner R (2000) Phreatomagmatic fragmentation. In: Sigurdsson H, Houghton B, McNutt S, Rymer H, Stix J (eds) Encyclopedia of volcanoes. Academic, New York, pp 431–445Google Scholar
  25. Pálsson S (1794) Ferðabók Sveins Pálssonar, Dagbækur og Ritgerðir 1791–1797, 2nd edition. Örn og Örlygur, ReykjavíkGoogle Scholar
  26. Robert E (1840) P. Gaimard voyage en Islande et au Grönlande. Mineralogie et Geologie, ParisGoogle Scholar
  27. Rossi MJ, Gudmundsson A (1996) The morphology and formation of flow-lobe tumuli on Icelandic shield volcanoes. J Volcanol Geotherm Res 72:291–308CrossRefGoogle Scholar
  28. Self S, Keszthelyi L, Thordarson T (1998) The importance of pahoehoe. Ann Rev Earth Planet Sci 26:81–110CrossRefGoogle Scholar
  29. Squyres SW, Clifford SM, Kuzmin RO, Zimbelman JR, Costard FM (1992) Ice in the Martian regolith. In: Kieffer HH, Jakosky BM, Snyder CW, Mathews MS (eds) Mars. University of Arizona Press, Tucson, pp 523–554Google Scholar
  30. Steingrímsson J (1788) Fulkomid Skrif um Sídueld. Safn til Sögu Íslands IV:8–69Google Scholar
  31. Steingrímsson J, Ólafsson S (1783) Einföld og sönn frásaga um jardeldshlaupid í Skaftafellssyslu árid 1783. Safn til Sögu Íslands IV:58–69Google Scholar
  32. Thorarinsson S (1951) Laxargljufur and Laxarhraun: a tephrachronological study. Geograf Annal H1(2):1–89CrossRefGoogle Scholar
  33. Thorarinsson S (1953) The crater groups in Iceland. Bull Volcanol 14:3–44CrossRefGoogle Scholar
  34. Thordarson T (1990) The eruption sequence and eruption behavior of the Skaftár Fires, 1783–85, Iceland: characteristics and distribution of eruption products. MS thesis, University of Texas at Arlington, ArlingtonGoogle Scholar
  35. Thordarson T, Self S (1993) The Laki (Skaftar Fires) and Grimsvotn eruptions in 1783–85. Bull Volcanol 55:233–263CrossRefGoogle Scholar
  36. Thordarson T, Self S, Oskarsson N, Hulsebosch T (1996) Sulfur, chlorine, and fluorine degassing and atmospheric loading by the 1783–1784 AD Laki (Skaftár Fires) eruption in Iceland. Bull Volcanol 58:205–225CrossRefGoogle Scholar
  37. Thordarson T, Miller DJ, Larsen G (1998a) New data on the Leidolfsfell cone group in South Iceland. Jökull 46:3–15Google Scholar
  38. Thordarson T, Self S (1998b) The Roza Member, Columbia River Basalt Group: a gigantic pahoehoe lava flow field formed by endogenous processes? J Geophys Res 103:27411–27445CrossRefGoogle Scholar
  39. Thordarson T (2003) The 1783–1785 A.D. Laki-Grímsvötn eruptions I: a critical look at the contemporary chronicles. Jökull 53:1–10Google Scholar
  40. Thordarson T, Self S (2003) Atmospheric and environmental effects of the 1783–1784 Laki eruption: a review and reassessment. J Geophys Res 108(D1):4011. doi: 10.1029/2001JD002042 Google Scholar
  41. Thordarson T, Larsen G, Stienþórsson S, Self S (2003) The 1783–1785 A.D. Laki-Grímsvötn eruptions II: appraisal based on contemporary accounts. Jökull 53:11–47Google Scholar
  42. Thoroddsen T (1879) Volcanic eruptions in Iceland in the year 1783. Geografisk Tidskrift 3:67–80Google Scholar
  43. Thoroddsen T (1894) Ferð um Vestur–Skaptafellssýslu sumarið 1893. Andvari 19:44–161Google Scholar
  44. Walker GPL (1991) Structure, and origin by injection of lava under surface crust, of tumuli, `lava rises´, `lava-rise pits´, and `lava-inflation clefts´ in Hawaii. Bull Volcanol 53:546–558CrossRefGoogle Scholar
  45. Wohletz KH, Sheridan MF (1983) Hydrovolcanic explosions II. Evolution of basaltic tuff rings and tuff cones. Am J Sci 283:385–413Google Scholar
  46. Wohletz KH (1983) Mechanisms of hydrovolcanic pyroclast formation: size, scanning electron microscopy, and experimental studies. J Volcanol Geotherm Res 17:31–63CrossRefGoogle Scholar
  47. Wohletz KH (1986) Explosive magma-water interactions: thermodynamics, explosion mechanisms, and field studies. Bull Volcanol 48:245–264CrossRefGoogle Scholar
  48. Wohletz KH (2002) Water/magma interaction: some theory and experiments on peperite formation. J Volcanol Geotherm Res 114:19–35CrossRefGoogle Scholar
  49. Woodcock D, Harris AJL (2006) The dynamics of a channel-fed lava flow on Pico Partido volcano, Lanzarote: evidence for a hydraulic jump? Bull Volcanol 69:207–125CrossRefGoogle Scholar
  50. Zimanowski B, Fröhlich G, Lorenz V (1991) Quantitative experiments on phreatomagmatic explosions. J Volcanol Geotherm Res 48:341–358CrossRefGoogle Scholar
  51. Zimanowski B (1998) Phreatomagmatic explosions. In: Freundt A, Rosi M (eds) From magma to tephra. Elsevier, Amsterdam, pp 25–554Google Scholar

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  • Christopher W. Hamilton
    • 1
    Email author
  • Thorvaldur Thordarson
    • 2
  • Sarah A. Fagents
    • 1
  1. 1.Hawai‘i Institute of Geophysics and PlanetologyUniversity of Hawai‘iHonoluluUSA
  2. 2.School of GeosciencesUniversity of EdinburghEdinburghUK

Personalised recommendations