Three-dimensional shallow crustal emplacement at the 9°03′N overlapping spreading center on the East Pacific Rise: Correlations between magnetization and tomographic images

Bazin, S.; Harding, A.J.; Kent, G.M.; Orcutt, J.A.; Tong, C.H.; Pye, J.W.; Singh, S.C.; Barton, P.J.; Sinha, M.C.; White, R.S.; Hobbs, R.W.; Van Avendonk, H.J.A.

doi:10.1029/2001jb000371

Three-dimensional shallow crustal emplacement at the 9°03′N overlapping spreading center on the East Pacific Rise: Correlations between magnetization and tomographic images

Bazin, S.; Harding, A.J.; Kent, G.M.; Orcutt, J.A.; Tong, C.H.; Pye, J.W.; Singh, S.C.; Barton, P.J.; Sinha, M.C.; White, R.S.; Hobbs, R.W.; Van Avendonk, H.J.A.

Authors

S. Bazin

A.J. Harding

G.M. Kent

J.A. Orcutt

C.H. Tong

J.W. Pye

S.C. Singh

P.J. Barton

M.C. Sinha

R.S. White

R.W. Hobbs

H.J.A. Van Avendonk

Abstract

We report a three-dimensional (3-D) seismic reflection and tomographic survey conducted at the 9°03′N overlapping spreading center (OSC) on the East Pacific Rise to understand crustal accretion at this feature. Inversions of travel time data from 19 ocean bottom hydrophones provide a 3-D image of the shallow velocity structure beneath the nontransform offset and associated discordance zone. Seismic analysis indicates that layer 2A thickness varies between 100 and 900 m and averages 430 m throughout the study area. The heterogeneous upper crustal structure at the OSC region contrasts with the simpler symmetric structure flanking the midsegments of the East Pacific Rise. The crust affected by the OSC migration carries evidence for the complex accretion at the axial discontinuity where the overlap basin may act as a lava pond. An area of thick layer 2A covers the southern half of the overlap basin and the propagating ridge tip and shows good correlation with a high magnetization region. Comparison of the magnetic field anomaly derived from the seismic structure model with the observed sea surface magnetic anomaly suggests that a significant portion of the high magnetization can be related to magnetic source thickness variation rather than solely to the geochemistry of the volcanic rocks.

Citation

Bazin, S., Harding, A., Kent, G., Orcutt, J., Tong, C., Pye, J., …Van Avendonk, H. (2001). Three-dimensional shallow crustal emplacement at the 9°03′N overlapping spreading center on the East Pacific Rise: Correlations between magnetization and tomographic images. Journal of Geophysical Research, 106(B8), 16101-16117. https://doi.org/10.1029/2001jb000371

Journal Article Type	Article
Publication Date	Aug 10, 2001
Deposit Date	Aug 17, 2015
Publicly Available Date	Aug 17, 2015
Journal	Journal of Geophysical Research. Solid Earth
Print ISSN	0148-0227
Publisher	Wiley
Peer Reviewed	Peer Reviewed
Volume	106
Issue	B8
Pages	16101-16117
DOI	https://doi.org/10.1029/2001jb000371

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Copyright Statement
Bazin, S., Harding, A. J., Kent, G. M., Orcutt, J. A., Tong, C. H., Pye, J. W., Singh, S. C., Barton, P. J., Sinha, M. C., White, R. S., Hobbs, R. W. and Van Avendonk, H. J. A., (2001), Three-dimensional shallow crustal emplacement at the 9°03′N overlapping spreading center on the East Pacific Rise: Correlations between magnetization and tomographic images, Journal of Geophysical Research: Solid Earth (1978–2012), 106(B8), 16101-16117, 10.1029/2001JB000371 (DOI). To view the published open abstract, go to http://dx.doi.org and enter the DOI.