Characteristics of Mantle Fabrics beneath the Southern-Central United States; Constraints from Shear-Wave Splitting Measurements


New shear-wave splitting measurements at permanent broadband seismic stations in the southern-central United States reveal the direction and strength of mantle fabrics, and provide constraints on models of the formation of these fabrics. For stations on the stable North American craton, correspondence between observed fast directions and the trend of Proterozoic and Paleozoic structures associated with rifts and orogenic belts implies a lithospheric origin of the observed anisotropy. The largest splitting times (up to 1.7 s) are observed at stations located in the ocean-continent transitional zone, in which the fast directions are parallel to the Gulf of Mexico continental margin. The parallelism and the geometry of the keel of the craton beneath the study area suggest that either asthenospheric flow around the keel of the North American craton, lithospheric fabrics developed during Mesozoic rifting, or a combination of the two are responsible for the observed anisotropy above the transitional crust.

Meeting Name

AGU Fall Meeting (2007: Dec. 10-14, San Francisco, CA)


Geosciences and Geological and Petroleum Engineering

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Article - Conference proceedings

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© 2007 American Geophysical Union (AGU), All rights reserved.

Publication Date

01 Dec 2007

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