Compressional and shear-wave velocity structure of the continent-ocean transition zone at the eastern Grand Banks, Newfoundland
Article first published online: 21 JUN 2013
©2013. American Geophysical Union. All Rights Reserved.
Geophysical Research Letters
Volume 40, Issue 12, pages 3014–3020, 28 June 2013
How to Cite
2013), Compressional and shear-wave velocity structure of the continent-ocean transition zone at the eastern Grand Banks, Newfoundland, Geophys. Res. Lett., 40, 3014–3020, doi:10.1002/grl.50511., , and (
- Issue published online: 18 JUL 2013
- Article first published online: 21 JUN 2013
- Accepted manuscript online: 29 APR 2013 10:52AM EST
- Manuscript Revised: 25 APR 2013
- Manuscript Accepted: 25 APR 2013
- Manuscript Received: 25 FEB 2013
- Continent-Ocean Transition Zone
 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 Vp / 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.