Bulletin of Volcanology

, 68:37 | Cite as

Gravitational spreading causes en-echelon diking along a rift zone of Madeira Archipelago: an experimental approach and implications for magma transport

  • Andreas KlügelEmail author
  • Thomas R. Walter
  • Stefanie Schwarz
  • Jörg Geldmacher
Research Article


Many volcanic rift zones show dikes that are oriented oblique rather than parallel to the morphological ridge axis. We have evidence that gravitational spreading of volcanoes may adjust the orientation of ascending dikes within the crust and segment them into en-echelon arrays. This is exemplified by the Desertas Islands which are the surface expression of a 60 km long submarine ridge in southeastern Madeira Archipelago. The azimuth of the main dike swarm (average = 145°) deviates significantly from that of the morphological ridge (163°) defining an en-echelon type arrangement. We propose that this deviation results from the gravitational stress field of the overlapping volcanic edifices, reinforced by volcano spreading on weak substratum. We tested our thesis experimentally by mounting analogue sand piles onto a sand and viscous PDMS substratum. Gravitational spreading of this setup produced en-echelon fractures that clearly mimic the dike orientations observed, with a deviation of 10°–32° between the model’s ridge axis and that of the main fracture swarm. Using simple numerical models of segmented dike intrusion we found systematic changes of displacement vectors with depth and also with distance to the rift zone resulting in a complex displacement field. We propose that at depth beneath the Desertas Islands, magmas ascended along the ridge to produce the overall present-day morphology. Above the oceanic basement, gravitational stress and volcano spreading adjusted the principal stress axes’ orientations causing counterclockwise dike rotation of up to 40°. This effect limits the possible extent of lateral dike propagation at shallow levels and may have strong control on rift evolution and flank stability. The results highlight the importance of gravitational stress as a major, if not dominant factor in the evolution of volcanic rift zones.


Rift zone Volcanic spreading En-echelon Volcano-tectonics Dikes Oceanic island Madeira Archipelago 



We are grateful to Directors H. Costa-Neves and S. Fontinha and the staff from the Parque Natural da Madeira for their kind permission and excellent support during our field studies on Ilhas Desertas. Without the professional help on the islands and the zodiac rides provided by the park rangers, this study would not have been possible. K. Schmidt and S. Tille helped us carry out the experiments. A. Gudmundsson and A. Borgia are thanked for their constructive reviews and critical suggestions that improved the manuscript. The research was supported by the Deutsche Forschungsgemeinschaft (DFG grant KL1313/2-1 and KL1313/4-2)


  1. Anderson EM (1951) The dynamics of faulting and dyke formation with applications to Britain. Oliver and Boyd, London, 206 ppGoogle Scholar
  2. Banda E, Ranero CR, Danobeitia JJ, Rivero A (1992) Seismic boundaries of the eastern Central Atlantic Mesozoic crust from multichannel seismic data. Geol Soc Am Bull 104:1340–1349CrossRefGoogle Scholar
  3. Borgia A (1994) Dynamic basis of volcanic spreading. J Geophys Res 99(B9):17791–17804CrossRefGoogle Scholar
  4. Borgia A, Delaney P, Denlinger RP (2000) Spreading volcanoes. Ann Rev Earth Planet Sci 28:539–570CrossRefGoogle Scholar
  5. Carracedo JC (1994) The Canary Islands: an example of structural control on the growth of large ocean-island volcanoes. J Volcanol Geotherm Res 60:225–241CrossRefGoogle Scholar
  6. Clifton A, Schlische R (2003) Fracture populations on the Reykjanes Peninsula, Iceland: Comparison with experimental clay models of oblique rifting. J Geophys Res 108(B2):2074, doi:10.1029/2001JB000635CrossRefGoogle Scholar
  7. Collier JS, Watts AB (2001) Lithospheric response to volcanic loading by the Canary Islands: constraints from seismic reflection data in their flexural moat. Geophys J Int 147:660–676CrossRefGoogle Scholar
  8. Comninou MA, Dunders J (1975) The angular dislocation in a halfspace. J Elasticity 5:203–216CrossRefGoogle Scholar
  9. Delaney PT, Pollard DD (1981) Deformation of host rocks and flow of magma during growth of minette dikes and breccia-bearing intrusions near Ship Rock, New Mexico. US Geol Surv Prof Pap 1202:61Google Scholar
  10. Dieterich JH (1988) Growth and persistence of Hawaiian volcanic rift zones. J Geophys Res 93(B5):4258–4270CrossRefGoogle Scholar
  11. Fiske RS, Jackson ED (1972) Orientation and growth of Hawaiian volcanic rifts: the effect of regional structure and gravitational stresses. Proc R Soc Lond A 329:299–326CrossRefGoogle Scholar
  12. Geldmacher J, Bogaard Pvd, Hoernle KA, Schmincke HU (2000) Ar age dating of the Madeira Archipelago and hotspot track (eastern North Atlantic). Geochemistry, Geophysics, Geosystems 1: Paper number 1999GC000018Google Scholar
  13. Grant JV, Kattenhorn SA (2004) Evolution of vertical faults at an extensional plate boundary, southwest Iceland. J Struct Geol 26:537–557CrossRefGoogle Scholar
  14. Gudmundsson A (1987) Geometry, formation and development of tectonic fractures on the Reykjanes Peninsula, Southwest Iceland. Tectonophysics 139:295–308CrossRefGoogle Scholar
  15. Gudmundsson A (1990) Dyke emplacement at divergent plate boundaries. In: Parker AJ, Rickwood PC, Tucker DH (eds) Mafic dykes and emplacement mechanisms. Proc Int Dyke Conf 2:47–62Google Scholar
  16. Gudmundsson A (1995) The geometry and growth of dykes. In: Baer G, Heimann A (eds) Physics and chemistry of dykes. Balkema, Rotterdam, Brookfield, pp 23–34Google Scholar
  17. Gudmundsson A (2000) Dynamics of volcanic systems in Iceland: Example of tectonism and volcanism at juxtaposed hot spot and mid-ocean ridge systems. Ann Rev Earth Planet Sci 28:107–140CrossRefGoogle Scholar
  18. Gudmundsson A (2002) Emplacement and arrest of sheets and dykes in central volcanoes. J Volcanol Geotherm Res 116:279–298CrossRefGoogle Scholar
  19. Jónsson S, Einarsson P, Sigmundsson F (1997) Extension across a divergent plate boundary, the Eastern Volcanic Rift Zone, south Iceland, 1967–1994, observed with GPS and electronic distance measurements. J Geophys Res 102:11913–11929CrossRefGoogle Scholar
  20. Klitgord KD, Schouten H (1986) Plate kinematics of the Central Atlantic. In: Vogt PR, Tucholke BE (eds) The geology of North America, vol. M, The Western North Atlantic Region. Geological Society of America, pp 351–378Google Scholar
  21. Lockwood JP, Dvorak JJ, English TT, Koyanagi RY, Okamura AT, Summers ML, Tanigawa WR (1987) Mauna Loa 1974–1984—A decade of intrusive and extrusive activity. In: Decker RW, Wright TW, Stauffer PH (eds) Volcanism in Hawaii, 2. US Geol Surv Prof Paper 1350, pp 537–570Google Scholar
  22. McGuire W, Pullen AD (1989) Location and orientation of eruptive fissures and feeder dykes at Mount Etna; Influence of gravitational and regional tectonic stress regimes. J Volcanol Geotherm Res 38:325–344CrossRefGoogle Scholar
  23. Merle O, Borgia A (1996) Scaled experiments of volcanic spreading. J Geophys Res 101:13805–13817CrossRefGoogle Scholar
  24. Moore JG, Normark WR, Holcomb RT (1994) Giant Hawaiian landslides. Ann Rev Earth Planet Sci 122:119–144CrossRefGoogle Scholar
  25. Nairn IA, Cole JW (1981) Basalt dikes in the 1886 Tarawera rift. New Zeal Jour Geol Geophys 24:585–592Google Scholar
  26. Okubo P, Benz HM, Chouet BA (1997) Imaging the crustal magma sources beneath Mauna Loa and Kilauea, Hawaii. Geology 25:867–870CrossRefGoogle Scholar
  27. Pollard DD, Segall P, Delaney PT (1982) Formation and interpretation of dilatant echelon cracks. Geol Soc Am Bull 93:1291–1303CrossRefGoogle Scholar
  28. Roest WR, Danobeitia JJ, Verhoef J, Collette BJ (1992) Magnetic anomalies in the Canary Basin and the Mesozoic evolution of the Central North Atlantic. Mar Geophys Res 14:1–24CrossRefGoogle Scholar
  29. Schwarz S, Klügel A, Wohlgemuth-Ueberwasser C (2004) Melt extraction pathways and stagnation depths beneath the Madeira and Desertas rift zones (NE Atlantic) inferred from barometric studies. Contrib Mineral Petrol 147:228–240CrossRefGoogle Scholar
  30. Schwarz S, Klügel A, Bogaard Pvd, Geldmacher J (2005) Internal structure and evolution of a volcanic rift system in the eastern North Atlantic: the Desertas rift zone, Madeira archipelago. J Volcanol Geotherm Res 141:123–155CrossRefGoogle Scholar
  31. Smith WHF, Sandwell DT (1997) Global sea floor topography from satellite altimetry and ship depth soundings. Science 277:1956–1962CrossRefGoogle Scholar
  32. Sneddon IN, Lowengrub M (1969) Crack problems in the classical theory of elasticity. Wiley, New YorkGoogle Scholar
  33. Thodarson T, Self S (1993) The Laki (Skaftár Fires) and Grímsvötn eruptions in 1783–1785. Bull Volcanol 55:233–263CrossRefGoogle Scholar
  34. Thomas A (1993) Poly3D: A Three-Dimensional, Polygonal Element, Displacement Discontinuity Boundary Element Computer Program with Applications to Fractures, Faults, and Cavities in the Earth’s Crust. M.S. thesis Thesis, Stanford University, CAGoogle Scholar
  35. Walker GPL (1987) The dike complex of Koolau volcano, Oahu: Internal structure of a Hawaiian rift zone. In: Decker RW, Wright TW, Stauffer PH (eds) Volcanism in Hawaii, 2. US Geol Surv Prof Paper 1350, pp 961–993Google Scholar
  36. Walker GPL (1992) “Coherent intrusion complexes” in large basaltic volcanoes - a new structural model. J Volcanol Geotherm Res 50:41–54CrossRefGoogle Scholar
  37. Walker GPL (1999) Volcanic rift zones and their intrusion swarms. J Volcanol Geotherm Res 94:21–34CrossRefGoogle Scholar
  38. Walter TR (2003) Buttressing and fractional spreading of Tenerife, an experimental approach on the formation of rift zones. Geophys Res Lett 30(6):1296 doi:10.1029/2002GL016610CrossRefGoogle Scholar
  39. Walter TR, Schmincke HU (2002) Rifting, recurrent landsliding and Miocene structural reorganization on NW-Tenerife (Canary Islands). Int J Earth Sci 91:615–628CrossRefGoogle Scholar
  40. Walter TR, Troll VR (2003) Experiments on rift zone evolution in unstable volcanic edifices. J Volcanol Geotherm Res 127:107–120CrossRefGoogle Scholar
  41. Watts AB, Peirce C, Collier J, Dalwood R, Canales JP, Henstock TJ (1997) A seismic study of lithospheric flexure in the vicinity of Tenerife, Canary Islands. Earth Planet Sci Lett 146:431–447CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • Andreas Klügel
    • 1
    Email author
  • Thomas R. Walter
    • 2
  • Stefanie Schwarz
    • 1
  • Jörg Geldmacher
    • 3
  1. 1.Universität Bremen, Fachbereich GeowissenschaftenBremenGermany
  2. 2.Marine Geology and Geophysics, RSMASUniversity of MiamiMiamiUSA
  3. 3.IFM-GEOMAR, Leibniz-Institute for Marine SciencesKielGermany

Personalised recommendations