Continuous Mantle Melt Supply beneath an Overlapping Spreading Center on the East Pacific Rise

Tomographic images of upper mantle velocity structure beneath an overlapping spreading center (OSC) on the East Pacific Rise indicate that this ridge axis discontinuity is underlain by a continuous region of low P-wave velocities. The anomalous structure can be explained by an approximately 16-kilom...

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Bibliographic Details
Published in:Science (American Association for the Advancement of Science) 2001-03, Vol.291 (5510), p.1955-1958
Main Authors: Dunn, Robert A., Toomey, Douglas R., Detrick, Robert S., William S. D. Wilcock
Format: Article
Language:English
Subjects:
Anisotropy
Applied geophysics
Azimuth
Crystalline rocks
Earth
Earth sciences
Earth, ocean, space
Exact sciences and technology
Fractions
Geology
Geophysical research
Igneous and metamorphic rocks petrology, volcanic processes, magmas
Imaging
Internal geophysics
Magma
Mantle
Marine
Mohorovicic discontinuity
Ocean floor
Refraction
Temperature
Three dimensional modeling
Travel time
Velocity
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Summary:Tomographic images of upper mantle velocity structure beneath an overlapping spreading center (OSC) on the East Pacific Rise indicate that this ridge axis discontinuity is underlain by a continuous region of low P-wave velocities. The anomalous structure can be explained by an approximately 16-kilometer-wide region of high temperatures and melt fractions of a few percent by volume. Our results show that OSCs are not necessarily associated with a discontinuity in melt supply and that both OSC limbs are supplied with melt from a mantle source located beneath the OSC. We conclude that tectonic segmentation of the ridge by OSCs is not the direct result of magmatic segmentation at mantle depths.
ISSN:0036-8075
1095-9203
DOI:10.1126/science.1057683