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TitreSubmarine moraines in Newfoundland coastal waters: implictions for the deglaciation of Newfoundland and adjacent areas
AuteurShaw, J
SourceQuaternary International vol. 99-100, 2003 p. 115-134,
LiensAbstract - Résumé
Séries alt.Commission géologique du Canada, Contributions aux publications extérieures 2002067
ÉditeurElsevier BV
Documentpublication en série
Mediapapier; en ligne; numérique
SNRC2C; 2D; 2E; 2F; 2L; 2M; 1K; 1L; 1M; 1N; 11I; 11O; 11P; 12A; 12B; 12G; 12H; 12I; 12P
Lat/Long OENS -60.5000 -52.0000 52.5000 46.0000
Sujetsmoraines; moraines sous-marines; évolution postglaciaire; dépôts glaciomarins; déglaciation; fjords; Wisconsinien; nappes glaciaires; transport par radeaux de glace; marges glaciaires; filons-couches; plate-forme continentale; sédimentologie; géologie des dépôts meubles/géomorphologie; Quaternaire
Illustrationslocation maps; cross-sections, stratigraphic; seismic profiles; geological sketch maps
Résumé(disponible en anglais seulement)
Submarine moraines near modern coasts of Newfoundland show regional variations in architecture. Off the west coast, arcuate moraines in shallow water were altered to varying degrees by postglacial sea-level lowering. Off the southwest coast, arcuate moraines on deep, fiord-mouth sills interdigitate with glaciomarine deposits whose maximum age is 14.17 ka BP. Off the northeast coast, submarine moraines are absent at the mouths of the deep fiords; morainal ridges outside the fiords are coast-parallel. It is proposed that the moraines formed during deglaciation of the region. The Late Wisconsinan ice sheet extended to the edge of the continental shelf, and was divided into catchments, with fast flow concentrated in deep channels. Ice calved back along channels, isolating the Newfoundland Ice Cap and ice caps on the offshore banks ca. 14 ka. Drawdown from the interior was localized in fiords, and ice margins stabilized just offshore, forming the submarine moraines described here. Off the southwest coasts, the ice margin was maintained for up to 1.5 ka at fiord mouths. Off the northeast coast, many of the deep, wide fiords are without sills, and retreat was nearly continual until the margin stabilized at fiord heads just before 13 ka.