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Seismic imaging of the Cocos plate subduction zone system in central Mexico

Kim, YoungHee and Miller, Meghan S. and Pearce, Frederick and Clayton, Robert W. (2012) Seismic imaging of the Cocos plate subduction zone system in central Mexico. Geochemistry, Geophysics, Geosystems, 13 (7). Art. No. Q07001. ISSN 1525-2027. http://resolver.caltech.edu/CaltechAUTHORS:20120807-103715823

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Abstract

Broadband data from the Meso-America Subduction Experiment (MASE) line in central Mexico were used to image the subducted Cocos plate and the overriding continental lithosphere beneath central Mexico using a generalized radon transform based migration. Our images provide insight into the process of subducting relatively young oceanic lithosphere and its complex geometry beneath continental North America. The converted and reverberated phase image shows complete horizontal tectonic underplating of the Cocos oceanic lithosphere beneath the North American continental lithosphere, with a clear image of a very thin low-velocity oceanic crust (7–8 km) which dips at 15–20 degrees at Acapulco then flattens approximately 300 km from the Middle America Trench. Farther inland the slab then appears to abruptly change from nearly horizontal to a steeply dipping geometry of approximately 75 degrees underneath the Trans-Mexican Volcanic Belt (TMVB). Where the slab bends underneath the TMVB, the migrated image depicts the transition from subducted oceanic Moho to continental Moho at ∼230 km from the coast, neither of which were clearly resolved in previous seismic images. The deeper seismic structure beneath the TMVB shows a prominent negative discontinuity (fast-to-slow) at ∼65–75 km within the upper mantle. This feature, which spans horizontally beneath the arc (∼100 km), may delineate the top of a layer of ponded partial melt.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1029/2012GC004033DOIArticle
http://www.agu.org/pubs/crossref/2012/2012GC004033.shtmlPublisherArticle
ORCID:
AuthorORCID
Clayton, Robert W.0000-0003-3323-3508
Additional Information:© 2012 American Geophysical Union. Received 9 January 2012; accepted 4 June 2012; published 7 July 2012. We thank entire MASE team for making the data available (http://www.tectonics.caltech.edu/mase/). Y. Kim is supported by the Gordon and Betty Moore Foundation through the Tectonics Observatory at California Institute of Technology (contribution number 190) and NSF award EAR 0609707. We thank G. Abers, M. Bostock, L. MacKenzie, and S. Rondenay for discussion on imaging the steeply dipping slab. We also thank X. Pérez-Campos for providing the local seismicity data, T. Chen for providing slab contour lines for Mexico subduction zone, and T. Song and S. Straub for comments on the melt feature underneath the arc in central Mexico. Finally, we thank the Editor J. Tyburczy, Associate Editor, J. Gu, and an anonymous reviewer for helpful comments, which greatly improved the paper.
Group:Caltech Tectonics Observatory, Seismological Laboratory
Funders:
Funding AgencyGrant Number
Gordon and Betty Moore FoundationUNSPECIFIED
NSFEAR 0609707
Subject Keywords:Mexico; inversion; mantle wedge; oceanic crust; subduction zone; volcanic arc
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Caltech Tectonics Observatory190
Record Number:CaltechAUTHORS:20120807-103715823
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20120807-103715823
Official Citation:Kim, Y., M. S. Miller, F. Pearce, and R. W. Clayton (2012), Seismic imaging of the Cocos plate subduction zone system in central Mexico, Geochem. Geophys. Geosyst., 13, Q07001, doi:10.1029/2012GC004033.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:32976
Collection:CaltechAUTHORS
Deposited By: Jason Perez
Deposited On:07 Aug 2012 20:34
Last Modified:31 Jan 2017 20:50

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