| Titre | Crustal structure of the central Nova Scotia margin off eastern Canada |
| Auteur | Wu, Y; Louden, K E; Funck, T; Jackson, H R; Dehler, S A |
| Source | Geophysical Journal International vol. 166, 2006 p. 878-906, https://doi.org/10.1111/j.1365-246X.2006.02991.x (Accès ouvert) |
| Année | 2006 |
| Séries alt. | Commission géologique du Canada, Contributions aux publications extérieures 2005124 |
| Éditeur | Oxford University Press (OUP) |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1111/j.1365-246X.2006.02991.x |
| Media | papier; en ligne; numérique |
| Formats | pdf (Adobe Acrobat Reader) |
| Province | Nouvelle-Écosse; Région extracotière |
| SNRC | 11C; 11D; 10N; 10O |
| Lat/Long OENS | -64.0000 -60.0000 45.0000 40.0000 |
| Sujets | structure de la croûte; marges continentales; levés de refraction sismiques; études de réfraction; volcanisme; levés de reflexion sismiques; études de réflexion; séismologie; serpentinisation; formation
de failles; géologie structurale; tectonique; géophysique |
| Illustrations | location maps; seismic profiles; cross-sections, structural; graphs |
| Programme | Consolidation du savoir géoscientifique du
Canada |
| Programme | CRSNG Conseil de recherches en sciences
naturelles et en génie du Canada |
| Résumé | (disponible en anglais seulement)
The central Nova Scotia margin off Eastern Canada is located at a transition from a volcanic margin in the south to a non-volcanic margin in the north. In order
to study this transition, a wide-angle refraction seismic line with dense airgun shots was acquired across the central Nova Scotia margin. The 500-km-long transect is coincident with previous deep reflection profiles across the Lahave Platform and
extending into the Sohm Abyssal Plain. A P-wave velocity model was developed from forward and inverse modelling of the wide-angle data from 21 ocean bottom seismometers and coincident normal-incidence reflection profiles. The velocity model shows
that the continental crust is divided into three layers with velocities of 5.5-6.9 km s-1. The maximum thickness is 36 km. A minor amount (-5 km) of thinning occurs beneath the outer shelf, while the major thinning to a thickness of 8 km occurs over
the slope region. The seaward limit of the continental crust consists of 5-km-thick highly faulted basement. There is no evidence for magmatic underplating beneath the continental crust. On the contrary, a 4-km-thick layer of partially serpentinized
mantle (7.6-7.95 km s-1) begins beneath the highly faulted continental crust, and extends ?200 km seawards, forming the lower part of the ocean-continent transition zone. The upper part of the transition zone consists of the highly faulted
continental crust and 4- to 5-km-thick initial oceanic crust. The continent-ocean boundary is moved ?50 km farther seawards compared to an earlier interpretation based only on reflection seismic data. The oceanic crust in the transition zone consists
of layer 2 and a high-velocity lower crustal layer. Layer 2 is 1-3 km thick with velocities of 5.6-6.0 km s-1. The high-velocity lower crustal layer is 1-2 km thick with velocities of 7.25-7.4 km s-1, suggesting a composite layer of serpentinized
peridotite and gabbroic layer 3. Oceanic crust with normal thickness of 5-7 km and more typical layer 3 with velocities of 6.95-7.3 km s?1 is observed at the seaward end of the profile. |
| GEOSCAN ID | 220722 |
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