| Titre | Dipping shear zones and the base of the crust in the Appalachians, offshore Canada |
| Auteur | Hall, J; Quinlan, G; Marillier, F; Keen, C |
| Source | Seismic probing of continents and their margins; Tectonophysics vol 173, no 1-4, test, 1990 p. 581-593, https://doi.org/10.1016/0040-1951(90)90247-6 |
| Année | 1990 |
| Séries alt. | Commission géologique du Canada, Contributions aux publications extérieures 24089 |
| Séries alt. | Lithoprobe Publication 96 |
| Séries alt. | International Lithosphere Program Contribution 154 |
| Éditeur | Elsevier BV |
| Réunion | International Meeting on Seismic Probing of Continents and their Margins; Canberra; AU; 19880701; juillet 1-8, 1988 |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1016/0040-1951(90)90247-6 |
| Media | papier; en ligne; numérique |
| Formats | pdf |
| Province | Région extracotière de l'est |
| Sujets | levés géophysiques; levés sismiques marins; marges continentales; failles; zones de cisaillement; zones orogéniques; océanographie; tectonophysique; lithosphère; gscconts |e Geological Survey of Canada,
Contribution Series |f Commission géologique du Canada, Contributions aux publications extérieures; lithcont |e Lithoprobe Publication |f Lithoprobe Publication; ilithopc |e International Lithosphere Program Contribution |f International Lithosphere
Program Contribution; géologie structurale; géophysique |
| Illustrations | sketch maps; seismic profiles |
| Résumé | (disponible en anglais seulement)
The Seismological character of the Appalachian mobile belt offshore from eastern Canada includes an unusual concentration of northwest-dipping reflectors which
appear to dip through sub-horizontal reflectors at the base of the crust. The geometry of these structures has been characterised by ray-trace migration. They are not point diffractors. They appear to dip at between 25 and 45°, but flatten upwards
towards a mid-crustal "bright" band and disappear downwards into the mantle. We interpret the reflectors as shear zones which ramp through the lower crust from a mid-crustal detachment to a diffuse and less reflective set of shears in the mantle. It
is suggested that the reflectors were caused by the collision of continental blocks at the final closure of the Iapetus Ocean, but may have been subject to later reactivation, especially during late Carboniferous strike-slip. |
| GEOSCAN ID | 458 |
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