GEOSCAN, résultats de la recherche


TitreCanada Basin revealed
AuteurMosher, D C; Shimeld, J; Hutchinson, D; Chian, D; Lebedeva-Ivanova, N; Jackson, R
SourceProceedings of the Arctic Technology Conference; 2012 p. 1-11
Séries alt.Secteur des sciences de la Terre, Contribution externe 20120454
ÉditeurOffshore Technology Conference
RéunionArctic Technology Conference; Houston; US; décembre 3-5, 2012
ProvinceRégion extracotière du nord
Lat/Long OENS-155.0000 -130.0000 80.0000 70.0000
Sujetsanalyses du bassin; bassins; bassins sédimentaires; antecedents de sedimentation; antécédents tectoniques; fosses d'effondrement; failles, extension; milieux tectoniques; évolution tectonique; interprétations tectoniques; interpretations sismiques; levés sismiques; levés de reflexion sismiques; Bassin de Canada ; tectonique; géologie marine; sédimentologie; stratigraphie; Mésozoïque; Crétacé; Cénozoïque
Illustrationslocation maps; profiles; stratigraphic columns
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)
More than 15,000 line-km of new regional seismic reflection and refraction data in the western Arctic Ocean provide insights into the tectonic and sedimentologic history of Canada Basin, permitting development of new geologic understanding in one of Earth's last frontiers. These new data support a rotational opening model for southern Canada Basin. There is a central basement ridge possibly representing an extinct spreading center with oceanic crustal velocities and blocky basement morphology characteristic of spreading centre crust surrounding this ridge. Basement elevation is lower in the south, mostly due to sediment loading subsidence. The sedimentary succession is thickest in the southern Beaufort Sea region, reaching more than 15 km, and generally thins to the north and west. In the north, grabens and half-grabens are indicative of extension. Alpha-Mendeleev Ridge is a large igneous province in northern Amerasia Basin, presumably emplaced synchronously with basin formation. It overprints most of northern Canada Basin structure. The seafloor and sedimentary succession of Canada Basin is remarkably flat-lying in its central region, with little bathymetric change over most of its extent. Reflections that correlate over 100s of kms comprise most of the succession and on-lap bathymetric and basement highs. They are interpreted as representing deposits from unconfined turbidity current flows. Sediment distribution patterns reflect changing source directions during the basin's history. Initially, probably late Cretaceous to Paleocene synrift sediments sourced from the Alaska and Mackenzie-Beaufort margins. This unit shows a progressive series of onlap unconformities with a younging trend towards Alpha and Northwind ridges, likely a response to contemporaneous subsidence. Sediment source direction appeared to shift to the Canadian Arctic Archipelago margin for the Eocene and Oligocene, likely due to uplift of Arctic islands during the Eurekan Orogeny. The final stage of sedimentation appears to be from the Mackenzie-Beaufort region for the Miocene and Pliocene when drainage patterns shifted in the Yukon and Alaska to the Mackenzie valley. Upturned reflections at onlap positions may indicate syn-depositional subsidence. There is little evidence, at least at a regional seismic data scale, of contemporaneous or post-depositional sediment reworking, suggesting little large-scale geostrophic or thermohaline-driven bottom current activity.
Résumé(Résumé en langage clair et simple, non publié)
De nouvelles données géophysiques dans l'haut Arctique acquises entre 2007 et 2011 fournissent une nouvelle compréhension géologique dans une des dernières frontières de la Terre. Avant 2007, peu de données existent dans ces régions, donc la formation de l'océan Arctique de l'ouest étais mal compris. Avec ces nouvelles données, nous savons maintenant que la structure du bassin océanique et comment il a rempli de sédiments.