Crust-mantle boundary in eastern North America, from the (oldest) craton to the (youngest) rift

Vadim Levin, Andrea Servali, Jill Van Tongeren, William Menke, Fiona Darbyshire

Research output: Chapter in Book/Report/Conference proceedingChapter

4 Scopus citations

Abstract

The North American continent consists of a set of Archean cratons, Proterozoic orogenic belts, and a sequence of Phanerozoic accreted terranes. We present an ∼1250-km-long seismological profile that crosses the Superior craton, Grenville Province, and Appalachian domains, with the goal of documenting the thickness, internal properties, and the nature of the lower boundary of the North American crust using uniform procedures for data selection, preparation, and analysis to ensure compatibility of the constraints we derive. Crustal properties show systematic differences between the three major tectonic domains. The Archean Superior Province is characterized by thin crust, sharp Moho, and low values of Vp/Vs ratio. The Pro-terozoic Grenville Province has some crustal thickness variation, near-uniform values of Vp/Vs, and consistently small values of Moho thickness. Of the three tectonic domains in the region, the Grenville Province has the thickest crust. Vp/Vs ratios are systematically higher than in the Superior Province. Within the Paleozoic Appalachian orogen, all parameters (crustal thickness, Moho thickness, Vp/Vs ratio) vary broadly over distances of 100 km or less, both across the strike and along it. Internal tectonic boundaries of the Appalachians do not appear to have clear signatures in crustal properties. Of the three major tectonic boundaries crossed by our transect, two have clear manifestations in the crustal structure. The Grenville front is associated with a change in crustal thickness and crustal composition (as reflected in Vp/Vs ratios). The Norumbega fault zone is at the apex of the regional thinning of the Appalachian crust. The Appalachian front is not associated with a major change in crustal properties; rather, it coincides with a zone of complex structure resulting from prior tectonic episodes, and thus presents a clear example of tectonic inheritance over successive Wilson cycles.

Original languageEnglish (US)
Title of host publicationThe Crust-Mantle and Lithosphere-Asthenosphere Boundaries
Subtitle of host publicationInsights from Xenoliths, Orogenic Deep Sections, and Geophysical Studies
EditorsGianluca Bianchini, Jean-Louis Bodinier, Marjorie Wilson, Roberto Braga
PublisherGeological Society of America
Pages107-131
Number of pages25
ISBN (Electronic)9780813725260
DOIs
StatePublished - 2017

Publication series

NameSpecial Paper of the Geological Society of America
Volume526
ISSN (Print)0072-1077

All Science Journal Classification (ASJC) codes

  • Geology

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    Levin, V., Servali, A., Van Tongeren, J., Menke, W., & Darbyshire, F. (2017). Crust-mantle boundary in eastern North America, from the (oldest) craton to the (youngest) rift. In G. Bianchini, J-L. Bodinier, M. Wilson, & R. Braga (Eds.), The Crust-Mantle and Lithosphere-Asthenosphere Boundaries: Insights from Xenoliths, Orogenic Deep Sections, and Geophysical Studies (pp. 107-131). (Special Paper of the Geological Society of America; Vol. 526). Geological Society of America. https://doi.org/10.1130/2017.2526(06)