GEOSCAN, résultats de la recherche


TitreErosional and depositional features of glacial meltwater discharges on the eastern Canadian continental margin
AuteurPiper, D J W; Deptuck, M E; Mosher, D C; Hughes Clarke, J E; Migeon, S
SourceApplication of the principles of seismic geomorphology to continental-slope and base-of-slope systems: case studies from seafloor and near-seafloor analogues; par Prather, B E (éd.); Deptuck, M E (éd.); Mohrig, D (éd.); Van Hoorn, B (éd.); Wynn, R B (éd.); SEPM (Society for Sedimentary Geology), Special Publication no. 99, 2012.,
Séries alt.Secteur des sciences de la Terre, Contribution externe 20090288
ÉditeurSEPM (Society for Sedimentary Geology)
Documentpublication en série
Mediapapier; en ligne; numérique
ProvinceRégion extracotière de l'est
SNRC1; 2; 3; 10; 11; 12; 13; 14; 20; 21; 22; 24
Lat/Long OENS -74.0000 -40.0000 62.0000 40.0000
Sujetsplate-forme continentale; érosion; milieu sédimentaire; modèles sédimentaires; analyses sédimentaires; chenaux d'eau de fonte; marges continentales, atlantique; marges continentales; bathymétrie; carottes; graviers; sables; turbidites; coulées de débris; cônes sous-marins; glacis continental; Pléistocène; chenaux; courants; profils sismiques; interpretations sismiques; sedimentation; Miocène; géologie marine; géologie des dépôts meubles/géomorphologie; géophysique; Quaternaire; Tertiaire
Illustrationssketch maps; analyses
ProgrammeAléas géologiques et contraintes à la mise en valeur des ressources extracôtières, Géosciences à l'appui de la gestion des océans
Résumé(disponible en anglais seulement)
Large-scale glacial meltwater discharges have long been recognized as important sedimentological agents on the eastern Canadian continental margin. Previous studies in Eastern Valley of Laurentian Fan and Orphan Basin have elucidated aspects of processes and timing of glacial discharges, principally from seismic-reflection profiles and deep-water sidescan sonar. New multibeam bathymetry and piston cores show evidence of important meltwater processes seaward of all transverse troughs on the continental shelf, from Hudson Strait to the Scotian margin. Meltwater cuts broad flat-floored valleys and sculpts residual buttes, depositing thick-bedded gravel and sand turbidites, and builds submarine fans. Based on morphology, a wide range of scales of meltwater discharge may take place. Meltwater is intimately linked with supply of fluid glacial diamict (till) that on gentler slopes (< 2.5°) creates glacigenic debris flows but on steeper slopes breaks up, entrains water, and transforms to create erosive turbidity currents. Three end-member processes are recognized on submarine fans seaward of transverse troughs that were occupied by ice streams: glacigenic debris flows, turbidity-current deposition of channel–levee complexes, and blocky mass-transport deposits resulting from debris avalanches. The relative importance of meltwater appears greater at lower than at higher latitudes, whereas the formation of glacigenic debris flows is dependent on gradient. Pleistocene processes have resulted in slopes that are graded, implying that most sand deposition was on the continental rise.