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TitreThe impact of the final Lake Agassiz flood recorded in northeast Newfoundland and northern Scotian shelves based on century-scale palynological data
AuteurLevac, E; Lewis, C F M; Miller, A A L
SourceAbrupt climate change: mechanisms, patterns, and impacts; par Rashid, H (éd.); Polyak, L (éd.); Mosley-Thompson, E (éd.); American Geophysical Union Geophysical Monograph vol. 193, 2011 p. 139-159, https://doi.org/10.1029/2010GM001051
Année2011
Séries alt.Secteur des sciences de la Terre, Contribution externe 20100120
ÉditeurAmerican Geophysical Union
RéunionAbrupt Climate change, an AGU Chapman Conference; Columbus, Ohio; US; juin 15-19, 2009
Documentpublication en série
Lang.anglais
DOIhttps://doi.org/10.1029/2010GM001051
Mediapapier; en ligne; numérique
Formatspdf
ProvinceRégion extracotière de l'est
Lat/Long OENS-58.0000 -56.0000 47.0000 45.0000
Lat/Long OENS-54.0000 -52.0000 52.0000 50.0000
Sujetsanalyses palynologiques; palynologie; palynostratigraphie; palynologie systématique; inondations; chenaux d'eau de fonte; drainage; configurations hydrographiques; analyses polliniques; stratigraphie pollinique; biostratigraphie; changement climatique; paléontologie; géologie marine; géologie des dépôts meubles/géomorphologie; Nature et environnement
Illustrationslocation maps; stratigraphic columns; plots; tables
ProgrammeGéoscience de la côte Est, Géoscience en mer
Résumé(disponible en anglais seulement)
Two high-resolution century-scale palynological records from the eastern Canadian margin were analyzed to estimate the impact of Lake Agassiz's final drainage at circa 8.3 ka on sea surface conditions and to track the path of the meltwater plume. Core HU87033-19 from Notre Dame Channel on Northeast Newfoundland Shelf contains four distinct detrital carbonate (DC) beds, known to be sediment transported from Hudson Strait and Hudson Bay, and one layer is coeval with the drainage of Lake Agassiz. Within that DC layer, significant changes in dinoflagellate cyst assemblages indicate lower sea surface temperatures and salinity. The drop in salinity is a doublet, suggesting two episodes of meltwater drainage. Core HU84011-12, from St. Anne's Basin, on the northern Scotian Shelf contains similar changes in dinoflagellate cyst assemblages at the time of the drainage, indicating sea surface cooling accompanied by a slight decrease in salinity. The impact of the meltwater was greater in the Notre Dame Channel. This suggests that most of the meltwater from the final drainages of Lake Agassiz flowed south over the Labrador and Northeast Newfoundland shelves and was not dispersed directly into the Labrador Sea. Instead, it was possibly dispersed into the slope water system and subsequently into the North Atlantic after flowing initially over the continental shelf. This is the first paper describing paleoecological data indicating the presence of the Agassiz meltwater along the eastern Canadian margin.
GEOSCAN ID286005