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Anisotropic uppermost mantle in young subducted slab underplating Central Mexico

Song, Teh-Ru Alex and Kim, YoungHee (2012) Anisotropic uppermost mantle in young subducted slab underplating Central Mexico. Nature Geoscience, 5 (1). pp. 55-59. ISSN 1752-0894. doi:10.1038/NGEO1342. https://resolver.caltech.edu/CaltechAUTHORS:20120125-080627986

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Abstract

Knowledge of the rate of plate-spreading at mid-ocean ridges is critical for estimating plate motions and the outward flux of heat from Earth’s interior. Magnetic lineations and anisotropy—crystals that have aligned themselves with mantle flow—preserved in oceanic lithosphere provide a means for estimating plate-spreading rates up to 180 million years ago. However, reconstructions beyond this time are difficult because most older oceanic lithosphere has been subducted into the mantle. Here we use converted seismic waveforms to show that anisotropy is preserved in the subducted part of the Cocos Plate beneath Central Mexico. We observe strong P- and S-wave anisotropy in the topmost 2–6 km of the subducted oceanic mantle. The strength of the anisotropy is comparable to that measured in the surface portion of the Cocos Plate. We also show that P-wave azimuthal anisotropy and plate-spreading rate at present-day mid-ocean ridges exhibit a linear relationship. On the basis of this relationship, we suggest that the subducted portion of the Cocos Plate formed at a half-spreading rate of about 8 cm yr^(−1) at the East Pacific Rise, about 15 million years ago. Our results imply that subducted oceanic lithosphere could preserve an archive of ancient plate-spreading rates on Earth.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1038/NGEO1342DOIUNSPECIFIED
http://www.nature.com/ngeo/journal/v5/n1/full/ngeo1342.htmlPublisherUNSPECIFIED
ORCID:
AuthorORCID
Song, Teh-Ru Alex0000-0003-3697-5881
Kim, YoungHee0000-0002-1111-632X
Additional Information:© 2012 Macmillan Publishers Limited. Received 24 March 2011; accepted 10 November 2011; published online 11 December 2011. We are grateful to the Incorporated Research Institutions for Seismology Data Management Center (IRIS-DMC) for making the data available. We thank A. Federiksen and M. Bostock for providing software for calculating receiver functions through dipping anisotropic layers, and H. Kawakatsu, P. Asimow and S. O'Reilly for the comments on lithospheric anisotropy, ophiolite assemblages and cratonic lithosphere formation during the early stage of this work. We acknowledge the MASE team for making the data available. We also thank D. Anderson and P. D. Asimow for help in reviewing an early draft of this paper. This study is supported by the Institute for Research on Earth Evolution (IFREE), Japan Agency for Marine-Earth Science and Technology (JAMSTEC) and the Tectonic Observatory at Caltech. Author contributions: T-R.A.S. initiated the project and carried out local waveform modelling. T-R.A.S. and Y.K. carried out receiver function analysis and modelling. T-R.A.S. and Y.K. wrote the manuscript.
Funders:
Funding AgencyGrant Number
Institute for Research on Earth Evolution (IFREE)UNSPECIFIED
Japan Agency for Marine-Earth Science and Technology (JAMSTEC)UNSPECIFIED
Caltech Tectonic ObservatoryUNSPECIFIED
Issue or Number:1
DOI:10.1038/NGEO1342
Record Number:CaltechAUTHORS:20120125-080627986
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20120125-080627986
Official Citation:Anisotropic uppermost mantle in young subducted slab underplating Central Mexico - pp55 - 59 Teh-Ru Alex Song & YoungHee Kim doi:10.1038/ngeo1342
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:28950
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:25 Jan 2012 16:28
Last Modified:09 Nov 2021 17:02

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