Crustal structure across the eastern North American margin from ambient noise tomography

Abstract Passive tectonic margins, like the eastern North American margin (ENAM), represent the meeting of oceanic and continental material where no active deformation is occurring. The recent ENAM Community Seismic Experiment provides an opportunity to examine the crustal structure across the ENAM...

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Main Authors: Colton Lynner, Robert W. Porritt
Format: Article
Language:English
Published: Wiley 2017-07-01
Series:Geophysical Research Letters
Subjects:
Online Access:https://doi.org/10.1002/2017GL073500
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author Colton Lynner
Robert W. Porritt
author_facet Colton Lynner
Robert W. Porritt
author_sort Colton Lynner
collection DOAJ
description Abstract Passive tectonic margins, like the eastern North American margin (ENAM), represent the meeting of oceanic and continental material where no active deformation is occurring. The recent ENAM Community Seismic Experiment provides an opportunity to examine the crustal structure across the ENAM owing to the simultaneous deployment of offshore and onshore seismic instrumentation. Using Rayleigh wave phase and group velocities derived from ambient noise data, we invert for shear velocity across the ENAM. We observe a region of transitional crustal thicknesses that connects the oceanic and continental crusts. Associated with the transitional crust is a localized positive gravitational anomaly. Farther east, the East Coast magnetic anomaly (ECMA) is located at the intersection of the transitional and oceanic crusts. We propose that underplating of dense magmatic material along the bottom of the transitional crust is responsible for the gravitational anomaly and that the ECMA demarks the location of initial oceanic crustal formation.
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spelling doaj-art-57291608202d4324be1ef9cfd60cf8f62025-08-20T03:10:28ZengWileyGeophysical Research Letters0094-82761944-80072017-07-0144136651665710.1002/2017GL073500Crustal structure across the eastern North American margin from ambient noise tomographyColton Lynner0Robert W. Porritt1Department of Geosciences University of Arizona Tucson Arizona USADepartment of Geosciences University of Arizona Tucson Arizona USAAbstract Passive tectonic margins, like the eastern North American margin (ENAM), represent the meeting of oceanic and continental material where no active deformation is occurring. The recent ENAM Community Seismic Experiment provides an opportunity to examine the crustal structure across the ENAM owing to the simultaneous deployment of offshore and onshore seismic instrumentation. Using Rayleigh wave phase and group velocities derived from ambient noise data, we invert for shear velocity across the ENAM. We observe a region of transitional crustal thicknesses that connects the oceanic and continental crusts. Associated with the transitional crust is a localized positive gravitational anomaly. Farther east, the East Coast magnetic anomaly (ECMA) is located at the intersection of the transitional and oceanic crusts. We propose that underplating of dense magmatic material along the bottom of the transitional crust is responsible for the gravitational anomaly and that the ECMA demarks the location of initial oceanic crustal formation.https://doi.org/10.1002/2017GL073500passive marginambient noiseeastern North American margincrustal structure
spellingShingle Colton Lynner
Robert W. Porritt
Crustal structure across the eastern North American margin from ambient noise tomography
Geophysical Research Letters
passive margin
ambient noise
eastern North American margin
crustal structure
title Crustal structure across the eastern North American margin from ambient noise tomography
title_full Crustal structure across the eastern North American margin from ambient noise tomography
title_fullStr Crustal structure across the eastern North American margin from ambient noise tomography
title_full_unstemmed Crustal structure across the eastern North American margin from ambient noise tomography
title_short Crustal structure across the eastern North American margin from ambient noise tomography
title_sort crustal structure across the eastern north american margin from ambient noise tomography
topic passive margin
ambient noise
eastern North American margin
crustal structure
url https://doi.org/10.1002/2017GL073500
work_keys_str_mv AT coltonlynner crustalstructureacrosstheeasternnorthamericanmarginfromambientnoisetomography
AT robertwporritt crustalstructureacrosstheeasternnorthamericanmarginfromambientnoisetomography