Influence of enhanced melt supply on upper crustal structure at a mid-ocean ridge discontinuity: A three-dimensional seismic tomographic study of 9°N East Pacific Rise - Archive ouverte HAL Access content directly
Journal Articles Journal of Geophysical Research Year : 2003

Influence of enhanced melt supply on upper crustal structure at a mid-ocean ridge discontinuity: A three-dimensional seismic tomographic study of 9°N East Pacific Rise

, , , , (1) , , , (1) , , ,
1
C. H. Tong
  • Function : Author
P. J. Barton
  • Function : Author
R. S. White
  • Function : Author
M. C. Sinha
  • Function : Author
J. W. Pye
  • Function : Author
R. W. Hobbs
  • Function : Author
A. J. Harding
  • Function : Author
G. M. Kent
  • Function : Author
J. A. Orcutt
  • Function : Author

Abstract

We present a three-dimensional upper crustal model of the 9°03'N overlapping spreading center (OSC) on the East Pacific Rise that assists in understanding the relationship between melt sills and upper crustal structure at a ridge discontinuity with enhanced melt supply at crustal levels. Our P wave velocity model obtained from tomographic inversion of ∼70,000 crustal first arrival travel times suggests that the geometry of extrusive emplacement are significantly different beneath the overlapping spreading limbs. Extrusive volcanic rocks above the western melt sill are inferred to be thin (∼250 m). More extensive accumulation of extrusives is inferred to the west than to the east of the western melt sill. The extrusive layer inferred above the eastern melt sill thickens from ∼350 (at the neovolcanic axis) to 550 m (to the west of the melt sill). Volcanic construction is likely to be significant in the formation of ridge crest morphology at the OSC, particularly at the tip of the eastern limb. On the basis of our interpretation of the velocity model, we propose that enhanced magma supply at crustal levels at the OSC may provide an effective mechanism for the migration of ridge discontinuities. This "dynamic magma supply model" may explain the commonly observed nonsteady migration pattern of ridge discontinuities by attributing this to the temporal fluctuations in melt availability to the overlapping spreading limbs.
Fichier principal
Vignette du fichier
Journal of Geophysical Research Solid Earth - 2003 - Tong - Influence of enhanced melt supply on upper crustal structure.pdf (4.74 Mo) Télécharger le fichier
Origin : Publisher files allowed on an open archive

Dates and versions

insu-03598409 , version 1 (06-03-2022)

Licence

Copyright

Identifiers

Cite

C. H. Tong, P. J. Barton, R. S. White, M. C. Sinha, S. C. Singh, et al.. Influence of enhanced melt supply on upper crustal structure at a mid-ocean ridge discontinuity: A three-dimensional seismic tomographic study of 9°N East Pacific Rise. Journal of Geophysical Research, 2003, 108, pp. 514-520. ⟨10.1029/2002JB002163⟩. ⟨insu-03598409⟩
55 View
13 Download

Altmetric

Share

Gmail Facebook Twitter LinkedIn More