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Hidden hotspot track beneath the eastern United States

Chu, Risheng and Leng, Wei and Helmberger, Don V. and Gurnis, Michael (2013) Hidden hotspot track beneath the eastern United States. Nature Geoscience, 6 (11). pp. 963-966. ISSN 1752-0894. http://resolver.caltech.edu/CaltechAUTHORS:20131203-111223741

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Abstract

Hotspot tracks are thought to be the surface expressions of tectonic plates moving over upwelling mantle plumes, and are characterized by volcanic activity that is age progressive. At present, most hotspot tracks are observed on oceanic or thin continental lithosphere. For old, thick continental lithosphere, such as the eastern United States, hotspot tracks are mainly inferred from sporadic diamondiferous kimberlites putatively sourced from the deep mantle. Here we use seismic waveforms initiated by the 2011 M_w 5.6 Virginia earthquake, recorded by the seismic observation network USArray, to analyse the structure of the continental lithosphere in the eastern United States. We identify an unexpected linear seismic anomaly in the lower lithosphere that has both a reduced P-wave velocity and high attenuation, and which we interpret as a hotspot track. The anomaly extends eastwards, from Missouri to Virginia, cross-cutting the New Madrid rift system, and then bends northwards. It has no clear relationship with the surface geology, but crosses a 75-million-year-old kimberlite in Kentucky. We use geodynamical modelling to show that an upwelling thermal mantle plume that interacts with the base of continental lithosphere can produce the observed seismic anomaly. We suggest that the hotspot track could be responsible for late Mesozoic reactivation of the New Madrid rift system and seismicity of the eastern United States.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1038/NGEO1949 DOIArticle
http://www.nature.com/ngeo/journal/v6/n11/full/ngeo1949.htmlPublisherArticle
http://rdcu.be/cmU1PublisherFree ReadCube access
Additional Information:© 2013 Macmillan Publishers Limited. Received 24 June 2013; accepted 14 August 2013; published online 15 September 2013. We would like to thank R. Cox and B. Steinberger for suggestions and comments that made significant improvements to the manuscript. All seismic waveform data were downloaded from IRIS data management centre. This work is supported by the National Science Foundation through grant numbers EAR-0810303, EAR-0855815, CMMI-1028978, EAR-1161046, EAR-1247022 and EAR-1053064. This is contribution number 10074 of the Division of Geological and Planetary Sciences, California Institute of Technology. Author contributions: R.C. and D.V.H. designed the seismic study and conducted the seismic data analysis. W.L. and M.G. designed the geodynamic models and W.L. carried out the modelling. R.C., D.V.H., W.L. and M.G. provided the joint seismic-geodynamic interpretation and wrote the manuscript.
Group:Seismological Laboratory
Funders:
Funding AgencyGrant Number
NSFEAR-0810303
NSFEAR-0855815
NSFCMMI-1028978
NSFEAR-1161046
NSFEAR-1247022
NSFEAR-1053064
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Caltech Division of Geological and Planetary Sciences10074
Record Number:CaltechAUTHORS:20131203-111223741
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20131203-111223741
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:42798
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:03 Dec 2013 20:33
Last Modified:11 Jun 2015 12:44

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