Mantle seismic structure beneath the United States spanning from the active western plate margin to the passive eastern margin was imaged with teleseismic P and S wave traveltime tomography including USArray data up to May 2014. To mitigate artifacts from crustal structure 5-40 s, Rayleigh wave phase velocities were used to create a 3-D starting model. Major features of the final P and S models include two distinct low-velocity anomalies at depths of ~60-300 km beneath the central and northern Appalachians and passive margin. The central Appalachian low-velocity anomaly coincides with Eocene basaltic magmatism, and the northern anomaly is located along the Cretaceous track of the Great Meteor hot spot. At depths of ~300-700 km beneath the central and eastern U.S. large high-velocity anomalies are inferred to be remnants of the Farallon slab that subducted prior to ~40 Ma during the Laramide orogeny. Key Points P wave and S wave mantle tomography spanning the contiguous U.S.Passive margin low-velocity anomalies linked to Cenozoic and Mesozoic volcanismSome Laramide-age slab fragments have yet to sink into the lower mantle
CITATION STYLE
Schmandt, B., & Lin, F. C. (2014). P and S wave tomography of the mantle beneath the United States. Geophysical Research Letters, 41(18), 6342–6349. https://doi.org/10.1002/2014GL061231
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