Compressional and shear-wave velocity structure of the continent-ocean transition zone at the eastern Grand Banks, Newfoundland

Drew R. Eddy, Harm J.A. Van Avendonk, Donna J. Shillington

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

The seismic structure of the continent-ocean transition (COT) at magma-poor rifted margins can explain geological processes leading to continental breakup. At the Newfoundland-Iberia rift, compressional seismic velocity (Vp) is interpreted with multichannel seismic reflections and drilling results to document continental crustal stretching and thinning, exhumation of the mantle, and incipient seafloor-spreading. However, Vp cannot uniquely constrain COT geology. We present an updated 2-D model for Vp and a new shear-wave velocity model (Vs) for SCREECH Line 2 on the Newfoundland margin using multichannel seismic reflections and coincident ocean-bottom seismometer refraction data. In shallow COT basement we find V p / Vs ratios average 1.77, which is normally too high for upper continental crust and too low for serpentinized mantle. This observation can be explained by stretching of a mafic middle and/or lower continental crust into the COT. We further support the presence of hydrated mantle peridotites at depth during rifting. Key Points Shear waves support stretched continental crust in Newfoundland rifted margin

Original languageEnglish (US)
Pages (from-to)3014-3020
Number of pages7
JournalGeophysical Research Letters
Volume40
Issue number12
DOIs
StatePublished - Jun 28 2013
Externally publishedYes

Keywords

  • Continent-Ocean Transition Zone
  • Extension
  • Newfoundland
  • Rifting

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

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