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Continental rupture and the creation of new crust in the Salton Trough rift, Southern California and northern Mexico: Results from the Salton Seismic Imaging Project

Han, Liang and Hole, John A. and Stock, Joann M. and Fuis, Gary S. and Kell, Annie and Driscoll, Neal W. and Kent, Graham M. and Harding, Alistair J. and Rymer, Michael J. and González-Fernández, Antonio and Lázaro-Mancilla, Octavio (2016) Continental rupture and the creation of new crust in the Salton Trough rift, Southern California and northern Mexico: Results from the Salton Seismic Imaging Project. Journal of Geophysical Research. Solid Earth, 121 (10). pp. 7469-7489. ISSN 2169-9313. http://resolver.caltech.edu/CaltechAUTHORS:20161222-100807138

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Abstract

A refraction and wide-angle reflection seismic profile along the axis of the Salton Trough, California and Mexico, was analyzed to constrain crustal and upper mantle seismic velocity structure during active continental rifting. From the northern Salton Sea to the southern Imperial Valley, the crust is 17–18 km thick and approximately one-dimensional. The transition at depth from Colorado River sediment to underlying crystalline rock is gradual and is not a depositional surface. The crystalline rock from ~3 to ~8 km depth is interpreted as sediment metamorphosed by high heat flow. Deeper felsic crystalline rock could be stretched preexisting crust or higher-grade metamorphosed sediment. The lower crust below ~12 km depth is interpreted to be gabbro emplaced by rift-related magmatic intrusion by underplating. Low upper mantle velocity indicates high temperature and partial melting. Under the Coachella Valley, sediment thins to the north and the underlying crystalline rock is interpreted as granitic basement. Mafic rock does not exist at 12–18 km depth as it does to the south, and a weak reflection suggests Moho at ~28 km depth. Structure in adjacent Mexico has slower midcrustal velocity, and rocks with mantle velocity must be much deeper than in the Imperial Valley. Slower velocity and thicker crust in the Coachella and Mexicali valleys define the rift zone between them to be >100 km wide in the direction of plate motion. North American lithosphere in the central Salton Trough has been rifted apart and is being replaced by new crust created by magmatism, sedimentation, and metamorphism.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1002/2016JB013139DOIArticle
http://onlinelibrary.wiley.com/doi/10.1002/2016JB013139/abstractPublisherArticle
ORCID:
AuthorORCID
Stock, Joann M.0000-0003-4816-7865
Additional Information:© 2016 American Geophysical Union. Received 2 MAY 2016; Accepted 8 OCT 2016; Accepted article online 11 OCT 2016; Published online 30 OCT 2016. This research was supported by NSF MARGINS and EarthScope grants 0742263 to J.A.H. and 0742253 to J.M.S., by NSF Marine Geology and Geophysics grant 0927446 to N.W.D. and G.M.K., by the U. S. Geological Survey's Multihazards Research Program, and by the Southern California Earthquake Center (SCEC) (contribution 6244). SCEC is funded by NSF cooperative agreement EAR-1033462 and USGS cooperative agreement G12AC20038. We thank the >90 field volunteers and USGS personnel who made data acquisition possible. Numerous landowners allowed access for shots and stations and are acknowledged in Rose et al. [2013]. Seismographs and technical support were provided by the IRIS-PASSCAL instrument facility; special thanks go to Mouse Reusch and Patrick Bastien from PASSCAL for their field and data efforts. We also thank the Associate Editor and two anonymous reviewers for their helpful and constructive reviews. The data have been archived at the IRIS DMC (ds.iris.edu/pic-ph5/metadata/SSIP/form.php).
Group:Seismological Laboratory
Funders:
Funding AgencyGrant Number
NSFOCE-0742263
NSFOCE-0742253
NSFOCE-0927446
Southern California Earthquake Center (SCEC)UNSPECIFIED
NSFEAR-1033462
USGSG12AC20038
Subject Keywords:active rifting; continental rifting; crustal structure; Salton Trough; controlled source seismic; seismic velocity
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Southern California Earthquake Center (SCEC)6244
Record Number:CaltechAUTHORS:20161222-100807138
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20161222-100807138
Official Citation:Han, L., et al. (2016), Continental rupture and the creation of new crust in the Salton Trough rift, Southern California and northern Mexico: Results from the Salton Seismic Imaging Project, J. Geophys. Res. Solid Earth, 121, 7469–7489, doi:10.1002/2016JB013139
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:73138
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:22 Dec 2016 18:25
Last Modified:03 Apr 2017 17:10

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