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TitreNew insights on Arctic crustal structure and tectonic framework from Canadian-U.S. joint icebreaker operations in the Amerasia Basin
AuteurOakey, G N; Chian, D; Shimeld, J; Jackson, H R; Hutchinson, D; Saltus, R W; Li, Q; Mosher, D; Miller, E; Evalgelatos, J
SourceGeological Society of America 2014 Convention - Proceedings ; .
Séries alt.Secteur des sciences de la Terre, Contribution externe 20160148
ÉditeurGeological Society of America
RéunionGeological Society of America 2014 Convention; Vancouver, BC; CA; Octobre 19-22, 2014
Lang.anglais
Mediapapier; en ligne; numérique
ProgrammePreparation of a submission for an extended continental shelf in the Atlantic and Arctic Oceans under UNCLOS, Délimitation du plateau continental du Canada en vertu de la Convention des Nations Unies sur le droit de la mer (UNCLOS)
Résumé(disponible en anglais seulement)
Canada and the United States conducted joint icebreaker operations in the Amerasia Basin from 2007 to 2011 to acquire over 15000 km of seismic reflection and bathymetry data. Over 170 expendable sonobuoys were deployed to collect p-wave refraction and wide angle reflection data. Dredge samples were collected from northern Chukchi Plateu and Nautilus Spur. These new data, combined with circum-Arctic bathymetry, gravity and magnetic compilations, greatly enhance onshore/offshore mapping of crustal domains and structural elements, in particular the Canadian and Alaskan margins, the deep Canada Basin, the Alpha Ridge, and Makarov Basin.
The two-icebreaker operations resulted in the high quality seismic reflection data. The short-offset (16 channel) data imaged the base of the sedimentary succession and structures within the upper crust. Basement morphology is highly varied and complex. Large grabens, basement ridges and seamounts are observed as well as broadly distributed volcanoclastics and localized volcanic flows and sill intrusions.
The sonobuoy results define the regional velocity structure of the sedimentary succession and were used to depth-convert the seismic reflection data. The velocity models also provide constraints on the composition of the sediments, and the crustal velocities allow quantitative mapping of continental, oceanic, and transitional domains.
2-D gravity and magnetic models have been generated along several of the seismic lines using the sonobuoy velocities to constrain density parameters. Laboratory measurements of the new grab samples show the velocity-density relationships are consistent with standard published curves. These models provide useful visualization of rift styles along the margins, and estimates of crustal thickness. Integrated with detailed interpretation of magnetic anomalies, the models allow for revised calculation of the direction and magnitude of overall extension for opening of the Canada Basin.
We highlight these and other results from the on-going Canadian/U.S. cooperation on Arctic geological and tectonic studies. We will present a summary of these results with recently published material into a new 'tectonic events' chart to continue the discussion on the timing and evolution of the Amerasia Basin.
Résumé(Résumé en langage clair et simple, non publié)
Le Canada et les États-Unis ont mené de 2007 à 2011 des opérations conjointes de déglaçage dans le bassin amérasien afin d'acquérir des données de sismique réflexion et des données bathymétriques sur plus de 15 000 km. Plus de 170 bouées acoustiques consommables ont été déployées pour recueillir des données de réfraction et de réflexion grand angle. Des échantillons de dragage ont été prélevés dans le nord du plateau Chukchi et sur l'éperon Nautilus. Ces nouvelles données, s'ajoutant aux compilations de données bathymétriques, gravimétriques et magnétiques de la région circumarctique, améliorent grandement la cartographie terrestre et extracôtière des domaines et des éléments structuraux de la croûte terrestre, notamment les marges du Canada et de l'Alaska, le profond bassin Canada, la dorsale Alpha et le bassin Makarov.
GEOSCAN ID299145