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TitleDistribution and morphology of inner-shelf sand bodies off southwest Newfoundland based on merged multibeam sonar and LiDAR data
AuthorShaw, J; Wu, Y; Potter, D P
SourceCanadian Journal of Earth Sciences vol. 57, no. 1, 2019 p. 114-122,
Alt SeriesNatural Resources Canada, Contribution Series 20180321
PublisherCanadian Science Publishing
Mediapaper; on-line; digital
File formatpdf
ProvinceNewfoundland and Labrador; Eastern offshore region
NTS11I; 11J; 11O; 11P
AreaIsland of Newfoundland; Cabot Strait; Laurentian Channel; Cape Anguille
Lat/Long WENS -60.0000 -57.0000 48.0000 46.0000
Subjectsmarine geology; surficial geology/geomorphology; geophysics; Science and Technology; Nature and Environment; marine sediments; sands; bedforms; morphology; geophysical surveys; acoustic surveys, marine; side-scan sonar; bathymetry; continental margins; continental shelf; coastal environment; nearshore environment; submarine features; submarine canyons; submarine troughs; sediment transport; oceanography; bottom currents
Illustrationslocation maps; geoscientific sketch maps; bathymetric profiles
ProgramPublic Safety Geoscience Public Safety Geoscience - Coordination
Released2019 05 29
AbstractThe inner shelf off southwest Newfoundland, bordering the Laurentian Channel, was mapped with multibeam sonar between depths of 200 m and ~20 m, overlapping with coverage by marine/terrestrial LiDAR from maximum depths of 30 m to above sea level. The new data provide the first clear view of linkages between terrestrial and nearshore coastal systems and the inner shelf. Offshore sand reservoirs associated with adjacent sandy coastal barriers and spits are thin (~2 m), and isolated from one another, so that bedrock is the dominant seafloor terrain on the inner most shelf. The offshore sand reservoirs link with complex nearshore bar systems, from which it is inferred that sediment exchange with terrestrial systems can occur. Several isolated sand bodies are interpreted as residuals from former coastal systems destroyed during the Holocene transgression. The new data reveal the unexpected existence of a submarine canyon that facilitates transport of sediment from the inner shelf into the deep glacial trough of Laurentian Channel.
Summary(Plain Language Summary, not published)
Combined multibeam sonar and LiDAR off southwest Newfoundland to map the seabed of the white zone - the zone of shallow water that was previously inaccessible to mapping. It is shown that the seafloor is mostly bedrock, with large sand patches that link with modern beach systems. The survey also revealed a previously unknown submarine canyon draining sand away from local beaches. The paper is being submitted to the journal TOGETHER with a second paper that applies the same methodology in the Arctic. By comparing the two environments we demonstrate that, because of sea ice and falling sea levels, the shallow seafloor of the Canadian Arctic Archipelago is very different from that of temperate regions, being characterized by well-preserved glacial terrains.

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