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TitleApplication of multibeam bathymetry to sea-level studies in Atlantic Canada
AuthorShaw, J; Courtney, R C; Fader, G B; Parrott, D R; Taylor, R B; Hughes Clarke, J E
SourceCanadian Coastal Conference 1997, proceedings/Conférence canadienne sur le littoral 1997, comptes rendus; 1997 p. 350-359
Alt SeriesGeological Survey of Canada, Contribution Series 1997045
PublisherCanadian Coastal Science and Engineering Association (Ottawa, ON, Canada)
Meeting1997 Canadian Coastal Conference / Conférence canadienne sur le littoral 1997; Guelph, ON; CA; May 21-24, 1997
ProvinceNew Brunswick; Nova Scotia; Newfoundland and Labrador
NTS1E; 1F; 1G; 1H; 11D; 11E; 11F; 11K; 11L; 12A; 12B; 12G; 12H; 21I
AreaAbegwelt Passage; Argentia; Chedabucto Bay; Codroy; Relds Island; St. George's Bay
Lat/Long WENS -66.0000 -52.0000 50.0000 44.0000
Subjectsgeophysics; marine geology; sedimentology; sonar surveys; bathymetry; sea level changes; sea level fluctuations; drumlins; moraines; landforms; glacial deposits
Illustrationslocation maps; bathymetric profiles; graphs
AbstractMultibeam sonar systems provide high-resolution shaded-relief bathymetric images of the seabed and images of backscatter intensity (that can be correlated with sediment type). Multibeam imagery provides evidence of lowered postglacial relative sea level (RSL) in coastal areas of Atlantic Canada. Submerged valleys that have been identified include meandering channels off Nova Scotia and Newfoundland, and a valley system in Northumberland Strait. Depositional coastal landforms that formed during the RSL lowstand include a gravel foreland in Chedabucto Bay, N.S. Horizontal platforms developed in glacial deposits by erosion in the paleo-surf zone are clearly seen. Examples include truncated drumlins (off Halifax, N.S.) and moraines (Argentia, Nfid.). The platform in St. George's Bay (Nfid.) is partly erosional but mostly depositional. Examples of constructional coastal landforms that were abandoned and overstepped during the Holocene transgression include a T-shaped gravel ridge in Chedabucto Bay that has modern analogs on the coast of Nova Scotia. Identification and interpretation of these features is leading to a better understanding of the Holocene transgression.