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TitreLatest Pleistocene ice-rafting events on the Scotian Margin (eastern Canada) and their relationship to Heinrich events
AuteurPiper, D J W; Skene, K I
SourcePaleoceanography vol. 13, no. 2, 1998 p. 205-214,
Séries alt.Commission géologique du Canada, Contributions aux publications extérieures 1997125
Documentpublication en série
Mediapapier; en ligne; numérique
ProvinceRégion extracotière de l'est
Lat/Long OENS -65.0000 -40.0000 48.0000 40.0000
Sujetscarottages par piston; marges continentales; marges continentales, atlantique; datations au radiocarbone; boues; transport par radeaux de glace; analyse granulométriques; courants de turbidite; géologie marine; géologie des dépôts meubles/géomorphologie
Illustrationslocation maps; tables; stratigraphic columns; graphs
ProgrammeCRSNG Conseil de recherches en sciences naturelles et en génie du Canada
Diffusé2010 05 04
Résumé(disponible en anglais seulement)
Piston cores from the continental margin off Nova Scotia show up to four discrete intervals of "brick-red sandy mud," which are up to 20 cm thick. The ages of these intervals are bracketed by several radiocarbon dates, and three fall in the range 12.5-14.1 ka (radiocarbon years with ?0.4 kyr reservoir correction). The youngest dates from ?10.4 ka, placing it within the Younger Dryas. The distribution of the beds and their petrographic character indicate a source in the Gulf of Saint Lawrence. The grain size of these beds suggests that they comprise a coarse component transported by ice rafting that diminishes distally and a fine component that represents suspension fallout from a surface plume and resulting nepheloid layers. Graded brick-red beds in some cores were probably redeposited from turbidity currents. The lowermost bed on the Laurentian Fan and East Scotian Rise is immediately overlain by a carbonate-rich interval that can be identified all around the margin of the Grand Banks. This interval is correlated with detrital carbonate bed DC-1 in the Labrador Sea and Heinrich event H1 in the North Atlantic. The sequential occurrence of the two beds suggests that they may be a response to the same trigger, probably sea level rise, but that the Gulf of Saint Lawrence source was more easily destabilized.