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TitleDown-canyon evolution of turbidity currents at a late-glacial ice margin: Halibut Canyon, offshore southeastern Canada
AuthorTang, M; Piper, D J WORCID logo
SourceMarine Geology vol. 424, 106182, 2020 p. 1-20,
Alt SeriesNatural Resources Canada, Contribution Series 20190311
Mediapaper; on-line; digital
File formatpdf
ProvinceEastern offshore region; Newfoundland and Labrador
AreaHalibut Canyon
Lat/Long WENS -55.6667 -54.6667 45.3333 44.6667
Subjectsmarine geology; surficial geology/geomorphology; sedimentology; stratigraphy; geochemistry; geochronology; geophysics; Nature and Environment; Science and Technology; marine sediments; turbidity currents; submarine features; submarine canyons; geological evolution; depositional history; lithofacies; glacial history; deglaciation; ice margins; marine sediment cores; x-ray fluorescence analyses; sedimentary structures; radiometric dating; radiocarbon dating; geophysical interpretations; seismic interpretations; grain size distribution; stratigraphic correlations; micropaleontology; microfossils; Newfoundland Ice Dome; Labrador Current; Diatoms; Foraminifera; cumulative effects; Phanerozoic; Cenozoic; Quaternary
Illustrationslocation maps; geoscientific sketch maps; 3-D diagrams; plots; seismic profiles; tables; correlation sections; profiles; photographs; geophysical images; frequency distribution diagrams; time series; models; schematic cross-sections; schematic representations
ProgramMarine Geoscience for Marine Spatial Planning
Released2020 03 18
AbstractTurbidity currents are the most voluminous sediment transport processes on the continental slope, and it is important to understand how they behave through canyon systems. This study investigated 7 cores from Halibut Canyon, located seaward of a small ice stream draining the Newfoundland Ice Dome. Cores were X-radiographed for sedimentary structures, sediment geochemistry was assessed by X-ray fluorescence scanning to determine provenance, and age was determined by AMS C-14 dating. High resolution seismic profiles and core records show three phases of canyon evolution: (1) canyon erosion by plunging hyperpycnal meltwater from shelf-edge ice at maximum ice extent. (2) During deglaciation, active canyon deposition of an inner levee by turbidity currents, adjacent to an erosional talweg system. Cores record this phase from the Younger Dryas (12 ka) to before H1 (16.5 ka). (3) Passive canyon fill during the Holocene by the alongslope Labrador Current. Evidence suggests that deposition from Laurentian Current dominated during Holocene, with only minor down-canyon sediment supply. In the active canyon deposition phase, turbidity currents were of variable size, reaching thicknesses >390 m at 40 km down canyon. Numbers of sand beds and mean grain size decrease down canyon, which results from rapid entrainment of ambient seawater on the steep gradient and a downflow thinning of the lower part of the current with fine sand in suspension. Silt becomes increasingly segregated from muds downcanyon as a result of floc break-up and re-formation. The processes inferred from Halibut Canyon are representative of other canyons on formerly glaciated margins.
Summary(Plain Language Summary, not published)
Description and interpretation of modern and late-glacial sedimentation processes in Halibut Canyon.

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