Springer Nature is making SARS-CoV-2 and COVID-19 research free. View research | View latest news | Sign up for updates

Unconventional maar diatreme and associated intrusions in the soft sediment-hosted Mardoux structure (Gergovie, France)

  • 438 Accesses

  • 14 Citations


A Miocene age volcanic-hypabyssal structure comprising volcaniclastic deposits and mafic intrusions is exposed with vertical relief of ∼110 m on the side of Gergovie Plateau (Auvergne, France). Three main volcaniclastic facies are: (1) Fluidal tuff breccia composed of juvenile basalt and sediment clasts with dominantly fluidal shapes, with several combinations of basalt and sediment within individual clasts. (2) Thickly bedded lapilli tuff composed of varying proportions of fine-grained sediment derived from Oligocene–Miocene lacustrine marls and mudstones and basaltic lapilli, blocks, and bombs. (3) Planar-bedded tuff forming thin beds of fine to coarse ash-size sedimentary material and basalt clasts. Intrusive bodies in the thickly bedded lapilli tuff range from irregularly shaped and anastomosing dikes and sills of meters to tens of meters in length, to a main feeder dike that is up to ∼20 m wide, and that flares into a spoon-shaped sill at ∼100 m in diameter and 10–20 m thick in the eastern part of the structure. Volcaniclastic deposits and structural features suggest that ascending magma entrained soft, saturated sediment host material into the feeder dike and erupted fluidal magma and wet sediment via weak, Strombolian-like explosions. Host sediment and erupted material subsided to replace the extracted sediments, producing the growth subsidence structure that is similar to upper diatreme facies in typical maar diatremes but lacks evidence for explosive disruption of diatreme fill. Irregularly shaped small intrusions extended from the main feeder dike into the diatreme, and many were disaggregated due to shifting and subsidence of diatreme fill and recycled via eruption. The Mardoux structure is an “unconventional” maar diatreme in that it was produced mainly by weak explosive activity rather than by violent phreatomagmatic explosions and is an example of complex coupling between soft sediment and ascending magma.

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

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13


  1. Andrews RG, White JDL, Dürig T, Zimanowski B (2013) Discrete blasts in granular material yield two-stage process of cavitation and granular fountaining. Geophys Res Lett. doi:10.1002/2013GL058526

  2. Brown RJ, Valentine GA (2013) Physical characteristics of kimberlite and basaltic intraplate volcanism, and implications of a biased kimberlite record. Geol Soc Am Bull 125:1224–1238. doi:10.1130/B30749.1

  3. Büchel G, Lorenz V (1993) Syn- and post-eruptive mechanism of the Alaska Ukinrek maars in 1977. In: Negendek JFW, Zolitschka B (eds) Paleolimnology of European maar lakes. Lecture Notes in Earth Sci: 49. Springer, Berlin, pp 15–60

  4. Büttner R, Zimanowski B (1998) Physics of thermohydraulic explosions. Phys Rev E 57:5726–5729

  5. Büttner R, Zimanowski B (2003) Phreatomagmatic explosions in subaqueous volcanism. In: White JDL, Smellie JL, Clague DA (eds) Explosive subaqueous volcanism, vol 140, Am Geophys Union Monograph Ser., pp 51–60

  6. Carrasco-Núñez G, Ort MH, Romero C (2007) Evolution and hydrological conditions of a maar volcano (Atexcac crater, Eastern Mexico). J Volcanol Geotherm Res 159:179–197

  7. Chazot G, Mergoil-Daniel J (2012) Co-eruption of carbonate and silicate magmas during volcanism in the Limagne graben (French Massif Central). Lithos 154:130–146

  8. Degeai J-P (2004) Mesure de l’érosion post-éruptive autour des cratères de maars en inversion de relief dans le Massif central français. Géomorphol: Relief Proc Environnem 4:285–304

  9. Degeai J-P, Pastre J-F (2008) Évolution morphostructurale du plateau volcano-sédimentaire de Gergovie au Miocène inférieur : implications géodynamiques sur la phase tardi-tectonique du rift de Limagne (Massif central, France). Rev Can Sci Terre 45:641–650. doi:10.1139/E08-018

  10. Fisher RV, Waters AC (1970) Base surge forms in maar volcanoes. Am J Sci 268:157–180

  11. Glangeaud P (1909) Les regions Volcaniques du Puy de Dome, Bulletin des services de la Carte Géologique de la France et des Topographies Souterraines, 123 tome XIX, pp. 180

  12. Goër de Herve A (2000) Peperites from the Limagne trench (Auvergne, French massif central): a distinctive facies of phreatomagmatic pyroclastics. History of a semantic drift. In: Leyrit H, Montenat C (eds) Volcaniclastic rocks, from magmas to sediments. Gordon and Beach Sci Publishers, Amsterdam, pp 91–110

  13. Graettinger AH, Valentine GA, Sonder I, Ross P-S, White JDL, Taddeucci J (2014) Maar-diatreme geometry and deposits: subsurface blast experiments with variable explosion depth. Geochem Geophys Geosys. doi:10.1002/2013GC005198

  14. Heiken G (1971) Tuff rings: examples from the Fort Rock-Christmas Lake Valley basin, south-central Oregon. J Geophys Res 76:5615–5626

  15. Hooten JA, Ort MH (2002) Peperite as a record of early-stage phreatomagmatic fragmentation processes: an example from the Hopi Buttes volcanic field, Navajo Nation, Arizona, USA. J Volcanol Geotherm Res 114:95–106

  16. Kienle J, Kyle PR, Self S, Motyka RJ, Lorenz V (1980) Ukinrek Maars, Alaska, I. April 1977 eruption sequence, petrology, and tectonic setting. J Volcanol Geotherm Res 7:11–37

  17. Kjarsgaard BA, Harvey S, McClintock M, Zonneveld JP, Du Plessis P, McNeil D, Heaman L (2009) Geology of the Orion South kimberlite, Fort à la Corne, Canada. Lithos 112:600–617

  18. Lefebvre NS, White JDL, Kjarsgarrd BA (2012) Spatter-dike reveals subterranean magma diversions: consequences for small multivent basaltic eruptions. Geology 40:423–426. doi:10.1130/G32794.1

  19. Lefebvre N, White JDL, Kjarsgaard BA (2013) Unbedded diatreme deposits reveal maar-diatreme-forming eruptive processes: standing Rocks West, Hopi Buttes, Navajo Nation, USA. Bull Volcanol 75:739. doi:10.1007/s00445-013-0739-9

  20. Lorenz V (1973) On the formation of maars. Bull Volcanol 37:183–204

  21. Lorenz V (1986) On the growth of maars and diatremes and its relevance to the formation of tuff-rings. Bull Volcanol 48:265–274

  22. Lorenz V (2009) The maar-diatreme volcano: a peculiar volcano type that largely prefers to work underground [abstract]. Proceedings, 3rd Int. Maar Conf., Malargüe, Argentina

  23. Lorenz V, Kurszlaukis S (2007) Root zone processes in the phreatomagmatic pipe emplacement model and consequences for the evolution of maar-diatreme volcanoes. J Volcanol Geotherm Res 159:4–32

  24. Lorenz V, Zimanowski B, Büttner R (2002) On the formation of deep-seated subterranean peperite-like magma-sediment mixtures. J Volcanol Geotherm Res 114:107–118

  25. Mathieu L, van Wyk de Vries B, Holohan EP, Troll VR (2008) Dykes, cups, saucers and sills: analogue experiments on magma intrusion into brittle rocks. Earth Planet Sci Lett 271:1–13

  26. McClintock M, White JDL (2006) Large phreatomagmatic vent complex at Coombs Hills, Antarctica: wet, explosive initiation of flood basalt volcanism in the Ferrar-Karoo LIP. Bull Volcanol 68:215–239

  27. McClintock M, Ross P-S, White JDL (2009) The importance of the transport system in shaping the growth and form of kimberlite volcanoes. Lithos 112:465–472

  28. Ort MH, Carrasco-Núñez G (2009) Lateral vent migration during phreatomagmatic and magmatic eruptions at Tecuitlapa Maar, east-central Mexico. J Volcanol Geotherm Res 181:67–77

  29. Pollard DD, Fletcher RC (2005) Fundamentals of structural geology. Cambridge Univ Press, Cambridge

  30. Ross P-S, White JDL (2006) Debris jets in contintental phreatomagmatic volcanoes: a field study on their subterranean deposits in the Coombs Hill vent complex, Antarctica. J Volcanol Geotherm Res 149:62–84

  31. Ross P-S, White JDL, Zimanowski B, Büttner R (2008a) Multiphase flow above explosion sites in debris-filled volcanic vents: insights from analogue experiments. J Volcanol Geotherm Res 178:104–112

  32. Ross P-S, White JDL, Zimanowski B, Büttner R (2008b) Rapid injection of particles and gas into non-fluidized granular material, and some volcanological implications. Bull Volcanol 70:1151–1168. doi:10.1007/s00445-008-0230-1

  33. Ross P-S, White JDL, Valentine GA, Taddeucci J, Sonder I, Andrews RG (2013) Experimental birth of a maar-diatreme volcano. J Volcanol Geotherm Res 260:1–12. doi:10.1016/j.jvolgeores.2013.05.005

  34. Rosseell J-B, White JDL, Houghton BF (2006) Complex bombs of phreatomagmatic eruptions: role of agglomeration and welding in vents of the 1886 Rotomahana eruption, Tarawera, New Zealand. J Geophys Res 111, B12205. doi:10.1029/2005JB004073

  35. Schipper CI, White JDL, Zimanowski B, Büttner R, Sonder I, Schmid A (2011) Experimental interaction of magma and “dirty” coolants. Earth Planet Sci Lett 303:323–336. doi:10.1016/j.epsl.2011.01.010

  36. Scrope GP (1858) The geology and extinct volcanoes of central France. John Murray, London

  37. Self S, Kienle J, Huot J-P (1980) Ukinrek Maars, Alaska, II. Deposits and formation of the 1977 craters. J Volcanol Geotherm Res 7:39–65

  38. Skilling IP, White JDL, McPhie J (2002) Peperite: a review of magma-sediment mingling. J Volcanol Geotherm Res 114:1–17

  39. Sottili G, Taddeucci J, Palladino DM, Gaeta M, Scarlato P, Ventura G (2009) Sub-sufrace dynamics and eruptive styles of maars in the Colli Albani Volcanic District, central Italy. J Volcanol Geotherm Res 180:189–202

  40. Sottili G, Palladino DM, Gaeta M, Masotta M (2011) Origins and energetics of maar volcanoes: examples from the ultrapotassic Sabatini Volcanic District (Roman Province, Central Italy). Bull Volcanol 74:163–186. doi:10.1007/s00445-011-0506-8

  41. Taddeucci J, Sottili G, Palladino DM, Ventura G, Scarlato P (2010) A note on maar eruption energetics: current models and their application. Bull Volcanol 72:75–83. doi:10.1007/s00445-009-0298-2

  42. Taddeucci J, Valentine GA, Sonder I, White JDL, Ross P-S, Scarlato P (2013) The effect of pre-existing craters on the initial development of explosive volcanic eruptions: an experimental investigation. Geophys Res Lett 40:507–510. doi:10.1002/grl.50176

  43. Valentine GA (2012) Shallow plumbing systems for small-volume basaltic volcanoes, 2: evidence from crustal xenoliths at scoria cones and maars. J Volcanol Geotherm Res 223–224:47–63. doi:10.1016/j.jvolgeores.2012.01.012

  44. Valentine GA, Gregg TKP (2008) Continental basaltic volcanoes—processes and problems. J Volcanol Geotherm Res 177:857–873

  45. Valentine GA, Groves KR (1996) Entrainment of country rock during basaltic eruptions of the Lucero volcanic field, New Mexico. J Geol 104:71–90

  46. Valentine GA, White JDL (2012) Revised conceptual model for maar-diatremes: subsurface processes, energetics, and eruptive products. Geology 40:1111–1114. doi:10.1130/G33411.1

  47. Valentine GA, Shufelt NL, Hintz ARL (2011) Models of maar volcanoes, Lunar Crater (Nevada, USA). Bull Volcanol 73:753–765. doi:10.1007/s00445-011-0451-6

  48. Valentine GA, White JDL, Ross P-S, Amin J, Taddeucci J, Sonder I, Johnson PJ (2012) Experimental craters formed by single and multiple buried explosions and implications for volcanic craters with emphasis on maars. Geophys Res Lett 39, L20301. doi:10.1029/2012GL053716

  49. van Otterloo J, Cas RAF (2013) Reconstructing the eruption magnitude and energy budgets for the pre-historic eruption of the monogenetic ∼5 ka Mt. Gambier Volcanic Complex, south-eastern Australia. Bull Volc 75:769, doi:10.1007/s00445-013-0769-3

  50. Waters AC, Fisher RV (1971) Base surges and their deposits: Capelinhos and Taal volcanoes. J Geophys Res 76:5596–5614

  51. White JDL (1991) Maar-diatreme phreatomagmatism at Hopi Buttes, Navajo Nation (Arizona), USA. Bull Volcanol 53:239–258

  52. White JDL (1996) Impure coolants and interaction dynamics of phreatomagmatic eruptions. J Volcanol Geotherm Res 74:155–170

  53. White JDL, Houghton BF (2006) Primary volcaniclastic rocks. Geology 34:677–680

  54. White JDL, McClintock MK (2001) Immense vent complex marks flood-basalt eruption in a wet, failed rift: Coombs Hills, Antarctica. Geology 29:935–938

  55. White JDL, Ross P-S (2011) Maar-diatreme volcanoes: a review. J Volcanol Geotherm Res 201:1–29

  56. White JDL, McPhie J, Skilling IP (2000) Peperite: a useful genetic term. Bull Volcanol 62:65–66

Download references


This work was conducted during faculty and student exchange under the joint EU-US INVOGE project. The authors thank Jamal Amin, Kelly Wooten, Andrew Harp, and Matthew Sweeney for assistance in the field and Alison Graettinger for reviewing an early version of the manuscript. Pierre-Simon Ross, Gerardo Carrasco, Volker Lorenz, and associate editor Steve Self, all provided helpful reviews that improved the manuscript.

Author information

Correspondence to Greg A. Valentine.

Additional information

Editorial responsibility: S. Self

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Valentine, G.A., van Wyk de Vries, B. Unconventional maar diatreme and associated intrusions in the soft sediment-hosted Mardoux structure (Gergovie, France). Bull Volcanol 76, 807 (2014). https://doi.org/10.1007/s00445-014-0807-9

Download citation


  • Maar
  • Diatreme
  • Phreatomagmatic
  • Dike
  • Sill