Lower-crustal intrusion on the North Atlantic continental margin

Robert White, Lindsay Smith, Alan Roberts, Phil Christie, Nick Kusznir, Alan Roberts, David Healy, R Spitzer, Alex Chappell, Jennifer Eccles, Rosie Fletcher, Neil Hurst, Zoe Lunnon, Craig Parkin, Vijay Tymms

Research output: Contribution to journalArticle

178 Citations (Scopus)

Abstract

When continents break apart, the rifting is sometimes accompanied by the production of large volumes of molten rock1, 2, 3. The total melt volume, however, is uncertain, because only part of it has erupted at the surface. Furthermore, the cause of the magmatism is still disputed—specifically, whether or not it is due to increased mantle temperatures. We recorded deep-penetration normal-incidence and wide-angle seismic profiles across the Faroe and Hatton Bank volcanic margins in the northeast Atlantic. Here we show that near the Faroe Islands, for every 1 km along strike, 360–400 km3 of basalt is extruded, while 540–600 km3 is intruded into the continent–ocean transition. We find that lower-crustal intrusions are focused mainly into a narrow zone 50 km wide on the transition, although extruded basalts flow more than 100 km from the rift. Seismic profiles show that the melt is intruded into the lower crust as sills, which cross-cut the continental fabric, rather than as an 'underplate' of 100 per cent melt, as has often been assumed. Evidence from the measured seismic velocities and from igneous thicknesses are consistent with the dominant control on melt production being increased mantle temperatures, with no requirement for either significant active small-scale mantle convection under the rift or the presence of fertile mantle at the time of continental break-up, as has previously been suggested for the North Atlantic Ocean4, 5, 6.
Original languageEnglish
Pages (from-to)460-464
JournalNature
Volume452
Issue number7186
DOIs
Publication statusPublished - 27 Mar 2008

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continental margin
melt
mantle
basalt
continental breakup
mantle convection
seismic velocity
sill
lower crust
rifting
magmatism
penetration
temperature

Keywords

  • ICELAND MANTLE PLUME
  • GREENLAND MARGIN
  • SPREADING CENTRE
  • OCEANIC CRUST
  • REFRACTION
  • THICKNESS
  • TOMOGRAPHY
  • REFLECTORS
  • DIMENSIONS
  • MAGMATISM

Cite this

White, R., Smith, L., Roberts, A., Christie, P., Kusznir, N., Roberts, A., ... Tymms, V. (2008). Lower-crustal intrusion on the North Atlantic continental margin. Nature, 452(7186), 460-464. https://doi.org/10.1038/nature06687

Lower-crustal intrusion on the North Atlantic continental margin. / White, Robert; Smith, Lindsay; Roberts, Alan; Christie, Phil; Kusznir, Nick; Roberts, Alan; Healy, David; Spitzer, R; Chappell, Alex; Eccles, Jennifer ; Fletcher, Rosie; Hurst, Neil; Lunnon, Zoe; Parkin, Craig; Tymms, Vijay.

In: Nature, Vol. 452, No. 7186, 27.03.2008, p. 460-464.

Research output: Contribution to journalArticle

White, R, Smith, L, Roberts, A, Christie, P, Kusznir, N, Roberts, A, Healy, D, Spitzer, R, Chappell, A, Eccles, J, Fletcher, R, Hurst, N, Lunnon, Z, Parkin, C & Tymms, V 2008, 'Lower-crustal intrusion on the North Atlantic continental margin', Nature, vol. 452, no. 7186, pp. 460-464. https://doi.org/10.1038/nature06687
White R, Smith L, Roberts A, Christie P, Kusznir N, Roberts A et al. Lower-crustal intrusion on the North Atlantic continental margin. Nature. 2008 Mar 27;452(7186):460-464. https://doi.org/10.1038/nature06687
White, Robert ; Smith, Lindsay ; Roberts, Alan ; Christie, Phil ; Kusznir, Nick ; Roberts, Alan ; Healy, David ; Spitzer, R ; Chappell, Alex ; Eccles, Jennifer ; Fletcher, Rosie ; Hurst, Neil ; Lunnon, Zoe ; Parkin, Craig ; Tymms, Vijay. / Lower-crustal intrusion on the North Atlantic continental margin. In: Nature. 2008 ; Vol. 452, No. 7186. pp. 460-464.
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AU - Healy, David

AU - Spitzer, R

AU - Chappell, Alex

AU - Eccles, Jennifer

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