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TitreThe Laurentide and Innuitian ice sheets during the Last Glacial Maximum
AuteurDyke, A S; Andrews, J T; Clark, P U; England, J H; Miller, G H; Shaw, J; Veillette, J J
SourceQuaternary Science Reviews 21, 1-3, 2002 p. 9-31, (Accès ouvert)
Séries alt.Commission géologique du Canada, Contributions aux publications extérieures 2001080
ÉditeurElsevier BV
Documentpublication en série
Mediapapier; en ligne; numérique
ProvinceCanada; Alberta; Colombie-Britannique; Manitoba; Nouveau-Brunswick; Terre-Neuve-et-Labrador; Territoires du Nord-Ouest; Nunavut; Nouvelle-Écosse; Ontario; Île-du-Prince-Édouard; Québec; Saskatchewan; Yukon; Région extracotière de l'est; Région extracotière du nord
SNRC1; 2; 3; 10; 11; 12; 13; 14; 15; 16; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 52; 53; 54; 55; 56; 57; 58; 59; 62; 63; 64; 65; 66; 67; 68; 69; 72; 73; 74; 75; 76; 77; 78; 79; 82; 83; 84; 85; 86; 87; 88; 89; 92; 93; 94; 95; 96; 97; 98; 99; 102; 103; 104; 105; 106; 107; 114O; 114P; 115; 116; 117; 120; 340; 560
Lat/Long OENS-141.0000 -50.0000 90.0000 41.7500
SujetsWisconsinien; marges glaciaires; retrait de la glace; changements du niveau de la mer; épaisseur de la glace; écoulement glaciaire; datation au radiocarbone; datations au C-14; sédiments marins; antecedents glaciaires; glaciation; glaciologie; déglaciation; régions extracôtières; elements glaciaires; dépôts glaciaires; dépôts glaciomarins; dépôts fluvioglaciaires; dépôts glaciolacustres; datation radiométrique; talus continental; sediments lacustres; etudes isotopiques; géochimie du sédiment; topographie glaciaire; échantillons carrotés; stratigraphie du till; fossiles; fluctuations climatiques; Calotte glaciaire Laurentide; Calotte glaciaire Innuitienne; Lac glaciaire d'Old Crow; Plate-Forme de Baffin; Plate-Forme Continentale de l'Est; Plate-Forme Continentale Polaire; Plate-Forme de Néo-écossaise; Plate-Forme de Magdalen; Calotte glaciaire du Groenland; lignes de partage glaciaire; géologie des dépôts meubles/géomorphologie; géochronologie; Quaternaire; Cénozoïque
Illustrationssketch maps; histograms; contour maps
ProgrammeProgramme du plateau continental polaire
Résumé(disponible en anglais seulement)
The Late Wisconsinan advance of the Laurentide Ice Sheet started from a Middle Wisconsinan interstadial minimum 27-30 14C ka BP when the ice margin approximately followed the boundary of the Canadian Shield. Ice extent in the Cordillera and in the High Arctic at that time was probably similar to present. Ice advanced to its Late Wisconsinan (stage 2) limit in the northwest, south, and northeast about 23-24 14C ka BP and in the southwest and far north about 20-21 14C ka BP. In comparison to some previous reconstructions of ice extent, our current reconstruction has substantially more Late Wisconsinan ice in the High Arctic, where an Innuitian Ice Sheet is generally acknowledged to have existed, in the Atlantic Provinces, where ice is now thought to have extended to the Continental Shelf edge in most places, and on eastern Baffin Island, where ice probably extended to the fiord mouths rather than to the fiord heads. Around most of the ice margin, the Late Wisconsinan maximum ice extent either exceeded the extent of earlier Wisconsinan advances or it was similar to the Early Wisconsinan advance. Ice marginal recession prior to 14 14C ka BP occurred mainly in deep water and along the southern terrestrial fringe. However, Heinrich event 1 probably drew down the entire central ice surface at 14.5 14C ka BP sufficiently to displace the Labrador Sector outflow centre 900 km eastward from the coast of Hudson Bay. The onset of substantial ice marginal recession occurred about 14 14C ka BP in the northwest, southwest, and south but not until about 10-11 14C ka BP in the northeast and in the High Arctic. Thus, the period of maximum ice extent in North America generally encompasses the interval from ~24/21 to 14 14C ka BP, or considerably longer than the duration of the LGM defined as occurring during a period of low global sea level as well as during a time of relative climate stability ~18 14C ka BP. The interval of advance of much of the Laurentide Ice Sheet to its maximum extent (between ~27 14C ka BP and ~24 14C ka BP) coincides with a suggested interval of rapid fall in global sea level to near LGM levels.