| Titre | A seismic refraction analysis of the Flemish Cap continental margin (E Canada): new evidence for asymmetric rifting from Goban Spur (NW Europe) |
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| Auteur | Gerlings, J; Louden, K E; Jackson, H R |
| Source | Geophysical Research Abstracts vol. 11, EGU2009-5448, 2009 p. 1  Accès ouvert |
| Liens | Online - En ligne
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| Image |  |
| Année | 2009 |
| Séries alt. | Secteur des sciences de la Terre, Contribution externe 20110135 |
| Réunion | European Geopysical Society; Vienna; AT; avril 19-24, 2009 |
| Document | publication en série |
| Lang. | anglais |
| Media | papier; en ligne; numérique |
| Formats | pdf (Adobe® Reader®) |
| Province | Région extracotière de l'est |
| Région | Flemish Cap; Goban Spur |
| Sujets | levés sismiques; levés de refraction sismiques; modèles sismiques; interpretations sismiques; levés géophysiques; décrochement horizontal; croûte continentale; croûte océanique; géophysique;
tectonique |
| Programme | Délimitation du plateau continental du Canada en vertu de la Convention des Nations Unies sur le droit de la mer (UNCLOS) |
| Diffusé | 2009 04 01 |
| Résumé | (disponible en anglais seulement)
The Flemish Cap - Goban Spur conjugate margin was one of the first margin pairs where deep seismic reflection data were used to determine the style of
non-volcanic rifting. These studies were used as evidence in support of a pure shear model of extension followed by an asymmetric breakup. In contrast, a more recent seismic refraction study of Goban Spur now indicates that extension is much more
complex and includes a wide transition zone interpreted as serpentinized mantle. In order to determine a complete conjugate section, the Flemish Cap margin has been re-examined with a 460-km-long refraction seismic profile, including dense airgun
shots to 21 OBS receivers, along the original deep MCS reflection profile. A P-wave velocity model has been developed by forward and inverse methods to define the crustal thickness, structure and composition of the crust and uppermost mantle along
the line. The velocity model displays continental crust with a maximum thickness of 30 km. The crust thins rapidly to a 6-km-thick, 30-km-wide zone of highly extended continental crust. Farther seaward, the velocities in the lower part of the crust
increase and this 85-km-wide transition zone is interpreted as partially serpentinized mantle. A sharp boundary separates the transition zone from 6-km-thick oceanic crust. The thin continental crust, transition zone and oceanic crust are overlain by
sediment layers of up to 3 km thickness on the thin continental crust decreasing to 1 km thickness on the oceanic crust. The transition zone on Flemish Cap displays somewhat higher velocities in the lower crust and Moho is a bit deeper than in the
zone of serpentinized mantle on Goban Spur but the transition zones have approximately similar width. On both margins a change in the velocity structure are observed at about the same place relative to magnetic anomaly 33-34. However, the thinning of
the continental crust occurs differently on the two margins. The crust thins more rapidly on the Flemish Cap than on the Goban Spur. Furthermore, a zone of thin continental crust is not observed on Goban Spur as observed on Flemish Cap. These new
results from Flemish Cap together with the recent results from Goban Spur show evidence of asymmetric rifting of the Flemish Cap ¿ Goban Spur conjugate margin. |
| GEOSCAN ID | 289078 |
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