GEOSCAN, résultats de la recherche


TitreStrike-slip tectonics and development of the Tertiary Queen Charlotte Basin, offshore western Canada: evidence from seismic reflection data
AuteurRohr, K M M; Dietrich, J R
SourceBasin Research vol. 4, no. 1, 1992 p. 1-20,
Séries alt.Commission géologique du Canada, Contributions aux publications extérieures 42691
Documentpublication en série
Mediapapier; en ligne; numérique
ProvinceColombie-Britannique; Région extracotière de l'ouest
SNRC103C; 103B; 103F; 103G; 103J; 103K; 103A; 102P; 102O; 102I
Lat/Long OENS-134.0000 -128.0000 56.0000 50.0000
Sujetslevés sismiques marins; levés de reflexion sismiques; milieux tectoniques; failles, décrochement; bassins; failles; mouvements des plaques; zones de cisaillement; talus continental; croûte continentale; marges continentales; frontières de plaques; Bassin de Queen Charlotte ; tectonique; géologie marine
Illustrationslocation maps; graphs; sesimic reflection profiles; stereograms; schematic diagrams
Diffusé2007 11 06
Résumé(disponible en anglais seulement)
Interpretation of seismic reflection data have led to a new model of the development of the Queen Charlotte Basin. New multi-channel data collected in 1988 and an extensive network of unpublished older single- and multi-channel profiles from industry image a complex network of sub-basins. Structural styles vary along the axis of the basin from broadly spaced mainly Ntrending sub-basins in Queen Charlotte Sound, to closely spaced NW-trending sub-basins in Hecate Strait, to an E-W en echelon belt of sub-basins in Dixon Entrance. Transtensional tectonics dominated in the Miocene and transpression dominated in the Pliocene except in Queen Charlotte Sound. The data we present prove that the origin of the basin is extensional and its most recent deformation is compressive. Evidence for the strike-slip origin of tectonism includes along-axis variations in structures, simultaneous extension and compression in adjacent sub-basins, lack of correlations across faults, and mixed normal and reverse faults within structures. We infer that the Pacific-North America plate boundary has been west of the Queen Charlotte Islands since the Miocene when relative plate motions have been dominantly strike-slip. The formation and development of the Queen Charlotte Basin is the result of distributed shear; by which a small percentage of the plate
motion has been taken up in a network of faults across the continental margin. As this region of crust deforms it interacts with neighbouring rigid crust resulting in extension dominating in the south of the basin and compression in the north. Continental crust adjacent to some transform plate boundaries can be sheared over a wide region ; the network of basins in southwestern California is a good analogue for the Queen Charlotte Basin.