GEOSCAN, résultats de la recherche


TitreSeabed habitat of a glaciated shelf, German Bank, Atlantic Canada
AuteurTodd, B J; Kostylev, V E; Smith, S J
SourceSeafloor geomorphology as benthic habitat; par Harris, P (éd.); Baker, E (éd.); 2012 p. 555-568,
Séries alt.Secteur des sciences de la Terre, Contribution externe 20100038
Mediapapier; en ligne; numérique
ProvinceRégion extracotière de l'est
Lat/Long OENS-66.7500 -65.5000 43.6667 43.0000
Sujetsfaunes; assemblages fauniques; marges continentales; dépôts glaciaires; tills; elements glaciaires; bathymétrie; topographie du fond océanique; topographie du fond océanique; peuplements biologiques; géologie marine; géologie des dépôts meubles/géomorphologie
Illustrationslocation maps; profiles; photographs
ProgrammeGéoscience en mer, Énergie renouvelable offshore
Résumé(disponible en anglais seulement)
An area of 5,320 km2 in water depths of 30 - 250 m has been mapped on German Bank on the southern Scotian Shelf in Atlantic Canada. The Scotian Shelf is a formerly glaciated continental margin characterized by a topographically rugged inner shelf. Bedrock is exposed at the seafloor on much of German Bank. Till occurs as a widespread sediment blanket and was deposited beneath or at the margins of the ice sheet directly onto bedrock during the Wisconsinan glaciation. Ice-distal glaciomarine silt overlies the older till and is primarily confined to small basins on the bank. Limited accumulations of postglacial sediments, composed of well-sorted sand grading to rounded and subrounded gravel, are also present. Analysis of seafloor photographs revealed broadscale gradients in benthic fauna composition dependent on water depth and covarying chemical and physical variables such as oxygen saturation and temperature variability. Statistical analyses of benthic megafauna and commercial species (lobster, scallops, crab) show that the distribution of benthic assemblages is associated with sediment type or broad-scale (kilometers to tens of kilometers) geomorphological features.