The Role of Deep-Water Sedimentary Processes in Shaping a Continental Margin: The Northwest Atlantic

TitleThe Role of Deep-Water Sedimentary Processes in Shaping a Continental Margin: The Northwest Atlantic
Publication TypeJournal Article
Year2017
AuthorsMosher, DC, Campbell, DC, Gardner, JV, Chaytor, JD, Rebesco, M
JournalMarine Geology
Volume393
Pages245-259
Date PublishedNovember 1
PublisherElsevier
Keywordscontourites, deep-water, geomorphology, geostrophic current, mass-transport deposits, mtd, northwest atlantic margin, turbidites

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

Publication Linkhttp://www.sciencedirect.com/science/article/pii/S0025322717304073
DOI10.1016/j.margeo.2017.08.018
Refereed DesignationRefereed
Region