Seismic imaging of mid-crustal structure beneath central and eastern North America: Possibly the elusive Grenville deformation?

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dc.contributor.authorLong, Maureen D.en
dc.contributor.authorBenoit, Margaret H.en
dc.contributor.authorAragon, John C.en
dc.contributor.authorKing, Scott D.en
dc.contributor.departmentGeosciencesen
dc.date.accessioned2020-06-29T13:22:38Zen
dc.date.available2020-06-29T13:22:38Zen
dc.date.issued2019-04en
dc.description.abstractThe ca. 1 Ga Grenville orogeny was a protracted mountain-building event that culminated in the collision of Laurentia and Amazonia and the formation of the Rodinia supercontinent. While the expression of Grenville orogenesis in present-day crustal structure has been extensively investigated in eastern Canada, evidence for contemporaneous crustal deformation is less well established beneath the eastern United States. Furthermore, the interpretation of a geophysical lineament through the U.S. midcontinent, typically inferred to be the Grenville deformation front, has recently been called into question; an alternative hypothesis is that this feature actually corresponds to an eastern arm of the Midcontinent Rift. Here we present P-to-S receiver functions computed for stations of the Mid-Atlantic Geophysical Integrative Collaboration (MAGIC) experiment, a dense array of broadband seismometers across the central Appalachians and midcontinent. We see evidence for a crustal negative velocity gradient that dips gently (dip angle <10 degrees) to the southeast and extends east from a location near the putative Grenville front, terminating near the Appalachian Mountains. While we cannot date this feature, its location and characteristics are consistent with a shallowly dipping, seismically anisotropic intracrustal shear zone associated with collisional deformation, perhaps during Grenville orogenesis. The similarity between this feature and similar mid-crustal detachments in other orogens, both ancient (Appalachians) and modern (Himalayas), suggests that this style of crustal deformation has been common in continental collisional orogens.en
dc.description.adminPublic domain – authored by a U.S. government employeeen
dc.description.notesSeismic data from the USArray Transportable Array, the U.S. National Seismic Network, and the Mid- Atlantic Geophysical Integrative Collaboration (MAGIC) experiment (https://doi.org/10.7914/SN/7A_2013) were accessed via the Data Management Center (http://ds.iris.edu) of the Incorporated Research Institutions for Seismology (IRIS). The MAGIC deployment was supported by the IRIS PASSCAL Instrument Center at the New Mexico Institute of Mining and Technology, Socorro, New Mexico, USA. The facilities of the IRIS Consortium are supported by the U.S. National Science Foundation (NSF) under Cooperative Agreement EAR-1261681 and the U.S. Department of Energy National Nuclear Security Administration. The MAGIC project was supported by the EarthScope and GeoPRISMS programs of the NSF via grant EAR-1251515 to Yale University, grant EAR-1251329 to the College of New Jersey, and grant EAR-1250988 to Virginia Polytechnic Institute and State University. The Generic Mapping Tools (Wessel and Smith, 1991) and FuncLab (Porritt and Miller, 2018) software programs were used in this work. The NSF I/D program helped support preparation of this manuscript. Any opinion, findings, and conclusions or recommendations expressed in this article are those of the authors and do not necessarily reflect the views of the NSF. We gratefully acknowledge comments from editor Dennis Brown, Carol Stein, and two anonymous reviewers.en
dc.description.sponsorshipIRIS PASSCAL Instrument Center at the New Mexico Institute of Mining and Technology, Socorro, New Mexico, USA; U.S. National Science Foundation (NSF)National Science Foundation (NSF) [EAR-1261681]; U.S. Department of Energy National Nuclear Security AdministrationNational Nuclear Security AdministrationUnited States Department of Energy (DOE); NSFNational Science Foundation (NSF) [EAR-1251515, EAR-1251329, EAR-1250988]en
dc.format.mimetypeapplication/pdfen
dc.identifier.doihttps://doi.org/10.1130/G46077.1en
dc.identifier.eissn1943-2682en
dc.identifier.issn0091-7613en
dc.identifier.issue4en
dc.identifier.urihttp://hdl.handle.net/10919/99162en
dc.identifier.volume47en
dc.language.isoenen
dc.rightsCreative Commons CC0 1.0 Universal Public Domain Dedicationen
dc.rights.urihttp://creativecommons.org/publicdomain/zero/1.0/en
dc.titleSeismic imaging of mid-crustal structure beneath central and eastern North America: Possibly the elusive Grenville deformation?en
dc.title.serialGeologyen
dc.typeArticle - Refereeden
dc.type.dcmitypeTexten
dc.type.dcmitypeStillImageen
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