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TitreRelationships among submarine instabilities, sea-level variations, and the presence of an ice sheet on the continental shelf: an example from the Verrill Canyon area, Scotian Shelf
AuteurMulder, T; Moran, K
SourcePaleoceanography vol. 10, no. 1, 1995 p. 137-154,
Séries alt.Commission géologique du Canada, Contributions aux publications extérieures 48793
Documentpublication en série
Mediapapier; en ligne; numérique
ProvinceRégion extracotière de l'est
Lat/Long OENS -62.0000 -61.3333 43.0000 42.3333
Sujetsniveaux paléomers; étages glaciaires; nappes glaciaires; talus continental; marges continentales; pressions interstitielles; resistance au cisaillement; dépôts de pression glaciaire; stabilité des pentes; glissements de pentes; caractéristiques sous-marines; géologie marine
Illustrationslocation maps; schematic diagrams; formulae; graphs
Diffusé2010 05 04
Résumé(disponible en anglais seulement)
Sea level low stands are associated with the growth of glacial ice sheets. During maximum stages of glaciation, ice sheets may extend to the outer continental shelf. These glacial maxima normally correspond to sea level low stands. Consequently, ice sheets may be supported directly by the seafloor inducing increased pore pressures in the sediment and increasing the overall bearing stresses on the margin. These stresses trigger undrained failure in upper slope sediment and bearing capacity failure in the middle to lower slope. After complete ice melting and dissipation of excess pore pressure, the inter-glacial sediments become overconsolidated. Shear resistance is higher, and no gravity or earthquake-induced failure occurs. The gravity events can only occur in underconsolidated and normally consolidated glacial and postglacial deposits. This explains the variation in volume and activity of mass wasting events during low and high sea level periods in areas where a glacial ice exists. Analyses of maximum ice loading events are presented for the Scotian slope. In contrast with traditional thought, these analyses suggest that ice loading, rather than high sedimentation rates, is the dominant mechanism for slope instability on glaciated margins.