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TitleNear-bed currents and sediment erosion potential on the shelf break and upper slope of Canadian Beaufort Sea - a regional synthesis
AuthorLi, M; King, E; Forest, A; Melling, H
SourceRFG 2018, Resources for Future Generations, technical program; 1258, 2018 p. 1
LinksOnline - En direct (PDF, 79 KB)
Year2018
Alt SeriesNatural Resources Canada, Contribution Series 20180122
PublisherRFG2018 Steering Committee
MeetingRFG2018 - Resources for Future Generations 2018; Vancouver, BC; CA; June 16-21, 2018
Documentbook
Lang.English
Mediaon-line; digital
File formatpdf
ProvinceNorthwest Territories; Northern offshore region
NTS97F/12; 97F/13; 97G/04; 97G/05; 97G/12; 97G/13; 107E; 107F; 107G; 107H; 117E/01; 117E/02; 117E/07; 117E/08; 117E/09; 117E/10; 117E/15; 117E/16; 117H/01; 117H/02; 117H/07; 117H/08; 117H/09; 117H/10; 117H/15; 117H/16
AreaBeaufort Sea; Amundsen Gulf
Lat/Long WENS-138.5000 -127.5000 72.0000 70.0000
Subjectsmarine geology; surficial geology/geomorphology; sedimentology; fossil fuels; engineering geology; continental margins; continental shelf; continental slope; bottom currents; erosion; petroleum industry; grain size analyses; oceanography; Holocene; Beaufort Shelf; Beaufort Slope; shelf breaks; near-bed currents; erosion threshold; Phanerozoic; Cenozoic; Quaternary
ProgramMarine Geohazards, Public Safety Geoscience
Released2018 06 01
AbstractAn erosional zone along the shelf break and upper slope of the Canadian Beaufort Sea has recently been attributed to episodic current erosion that intensified in the mid Holocene. This study aims to develop a regional understanding of the magnitude and frequency of near-bed currents and sediment erosion towards safe and sustainable energy development in the Canadian Arctic. Limited existing bottom current data as well as that extrapolated downward from water-column mooring data have been compiled for geographic areas covering the western, central and eastern Beaufort Shelf. The time series of the bottom current data have been integrated with sediment grain size data and the threshold for sediment erosion to compute the level and time percentage of erosion threshold exceedance for the selected along-shelf geographic areas. At the shelf break, the 95 percentile current speeds range 17-25 cm/s and the strong currents cause sediment erosion in 3.4-12% of the time. Current intensity and sediment erosion frequency decrease significantly on the slightly deeper upper slope where the 95 percentile current speeds range 13-17 cm/s and sediment erosion frequency from 2-3% of the time. The analysis of true measured bottom currents also firmly establishes that the current intensity and sediment erosion frequency decrease from the west to the east along the shelf break. However, no clear trend can be established yet on the upper slope due to uncertainty of the vertically extrapolated current data. Near-bed currents and estimated sediment erosion frequency on the Beaufort shelf break and upper slope demonstrate strong seasonal patterns and inter-annual variabilities. These variabilities are likely due to the spatial and temporal variation of the relative impact from various oceanographic processes, including cascading cold dense waters, formation and advection of eddies, and storm-induced upwelling and downwelling.
Summary(Plain Language Summary, not published)
An erosional zone has recently been mapped along the shelf break and upper slope of the Canadian Beaufort Sea. Measured or extrapolated near-bottom current data have been compiled for several along-shelf geographic areas. The bottom current data have been compared with the threshold for sediment erosion to compute the level and time percentage of seabed erosion. At the shelf break, the 95 percentile current speeds range 17-25 cm/s and cause sediment erosion in 3.4-12% of the time. On the upper slope in slightly deep water, the 95 percentile current speeds are 13-17 cm/s and sediment erosion occurs in 2-3% of the time. The current intensity and sediment erosion frequency are also found to decrease from the west to the east along the shelf break. The cross-slope variation of the current and sediment erosion intensity are in qualitative agreement with the spatial pattern of the mapped erosional zone on the Beaufort shelf break and upper slope.
GEOSCAN ID308385