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TitreThe role of deep-water sedimentary processes in shaping a continental margin: The Northwest Atlantic
AuteurMosher, D C; Campbell, D C; Gardner, J V; Piper, D J W; Chaytor, J D; Rebesco, M
SourceMarine Geology 2017., https://doi.org/10.1016/j.margeo.2017.08.018 (Accès ouvert)
Année2017
Séries alt.Secteur des sciences de la Terre, Contribution externe 20160218
ÉditeurElsevier
Documentpublication en série
Lang.anglais
DOIhttps://doi.org/10.1016/j.margeo.2017.08.018
Mediapapier; en ligne; numérique
Formatspdf
ProvinceRégion extracotière de l'est
Lat/Long OENS -70.0000 -50.0000 65.0000 30.0000
Sujetsantécédents tectoniques; sedimentation; turbidite; courants de turbidite; turbidites; contourites; topographie du fond océanique; bathymétrie; classification des formes de relief; talus continental; marges continentales, atlantique; marges continentales; glissements de pentes; géologie des dépôts meubles/géomorphologie; géologie marine
Illustrationslocation maps; graphs; tables; seismic reflection profiles; diagrams
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)
Diffusé2017 09 01
Résumé(disponible en anglais seulement)
The tectonic history of a margin dictates its general shape; however, its geomorphology is generally transformed by deep-sea sedimentary processes. The objective of this study is to show the influences of turbidity currents, contour currents and sediment mass failures on the geomorphology of the deep-water northwestern Atlantic margin (NWAM) between Blake Ridge and Hudson Trough, spanning about 32° of latitude and the shelf edge to the abyssal plain. This assessment is based on new multibeam echosounder data, global bathymetric models and sub-surface geophysical information.
The deep-water NWAM is divided into four broad geomorphologic classifications based on their bathymetric shape: graded, above-grade, stepped and out-of-grade. These shapes were created as a function of the balance between sediment accumulation and removal that in turn were related to sedimentary processes and slope-accommodation. This descriptive method of classifying continental margins, while being non-interpretative, is more informative than the conventional continental shelf, slope and rise classification, and better facilitates interpretation concerning dominant sedimentary processes.
Areas of the margin dominated by turbidity currents and slope by-pass developed graded slopes. If sediments did not by-pass the slope due to accommodation then an above grade or stepped slope resulted. Geostrophic currents created sedimentary bodies of a variety of forms and positions along the NWAM. Detached drifts form linear, above-grade slopes along their crests from the shelf edge to the deep basin. Plastered drifts formed stepped slope profiles. Sediment mass failure has had a variety of consequences on the margin morphology; large mass-failures created out-of-grade profiles, whereas smaller mass failures tended to remain on the slope and formed above-grade profiles at trough-mouth fans, or nearly graded profiles, such as offshore Cape Fear.
Résumé(Résumé en langage clair et simple, non publié)
Cet article présente une évaluation quantitative régionale de la morphologie de la marge de l'Atlantique à partir de Blake Ridge au large SE USA à la mer du Nord du Labrador. Le document évalue le rôle des différents processus géologiques (mouvements de masse, les courants de turbidité, le long de la pente des courants de fond) en affectant la forme de la marge.
GEOSCAN ID299328