Characterization of sills associated with the U reflection on the Newfoundland margin : evidence for widespread early post-rift magmatism on a magma-poor rifted margin


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dc.contributor.author Peron-Pinvidic, Gwenn
dc.contributor.author Shillington, Donna J.
dc.contributor.author Tucholke, Brian E.
dc.date.accessioned 2010-06-28T15:48:44Z
dc.date.available 2010-06-28T15:48:44Z
dc.date.issued 2010-05-25
dc.identifier.citation Geophysical Journal International 182 (2010): 113-136 en_US
dc.identifier.uri http://hdl.handle.net/1912/3698
dc.description Author Posting. © The Authors, 2010. This article is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in Geophysical Journal International 182 (2010): 113-136, doi:10.1111/j.1365-246X.2010.04635.x. en_US
dc.description.abstract Drilling during ODP Leg 210 penetrated two post-rift sills (dated as ∼105.3 and ∼97.8 Ma) in the deep sediments overlying basement of the continent–ocean transition zone on the magma-poor Newfoundland margin. The sill emplacement post-dated the onset of seafloor spreading by at least 7–15 Myr. The shallower of the two sills coincides with the high-amplitude U reflection observed throughout the deep Newfoundland Basin, and strong reflectivity in the sub-U sequence suggests that a number of other sills are present there. In this paper, we use multichannel seismic reflection data and synthetic seismograms to investigate the nature, magnitude and extent of this post-rift magmatism in the deep basin. Features observed in seismic profiles that we attribute to sill injection include high-amplitude reflections with geometries characteristic of intrusions such as step-like aspect; abrupt endings, disruptions and junctions of reflections; finger-like forms; differential compaction around possible loci of magma injection and disruption of overlying sediments by apparent fluid venting. Interpreted sills occur only over transitional basement that probably consists of a mixture of serpentinized peridotite and highly thinned continental crust, and they cover an area of ∼80 000 km2. From analysis of synthetic seismograms, we estimate that sill intrusions may comprise ∼26 per cent of the sub-U high-reflectivity sequence, which yields a crude estimate of ∼5800 km3 for the total volume of sills emplaced by post-rift magmatism. This is significant for a margin usually described as 'non-volcanic'. We discuss competing hypotheses about the source of the magmatism, which is still uncertain. en_US
dc.description.sponsorship G. Peron-Pinvidic's post-doctoral research at the University of Strasbourg and Woods Hole Oceanographic Institution was supported by TOTAL. B. Tucholke's research was supported by NSF grant OCE0647035. Multichannel seismic field programs that provided much of the data used for this research were supported by NSF grants OCE839085, OCE830823 and OCE9819053. en_US
dc.format.mimetype application/pdf
dc.language.iso en_US en_US
dc.publisher John Wiley & Sons en_US
dc.relation.uri http://dx.doi.org/10.1111/j.1365-246X.2010.04635.x
dc.subject Ocean drilling en_US
dc.subject Continental margins: divergent en_US
dc.subject Hotspots en_US
dc.subject Atlantic Ocean en_US
dc.title Characterization of sills associated with the U reflection on the Newfoundland margin : evidence for widespread early post-rift magmatism on a magma-poor rifted margin en_US
dc.type Article en_US
dc.identifier.doi 10.1111/j.1365-246X.2010.04635.x

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