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TitreStratigraphy and Late Pleistocene-Holocene history of Effingham Inlet, B.C., results from MONA core MD02-2494 and GSC freeze cores
AuteurDallimore, A; Enkin, R J; Baker, J; Pienitz, R
SourceCommission géologique du Canada, Dossier public 5930, 2009, 16 pages; 1 CD-ROM, (Accès ouvert)
ÉditeurRessources naturelles Canada
Documentdossier public
MediaCD-ROM; numérique; en ligne
Formatspdf (Adobe® Reader® is included / est fourni); doc; xls
ProvinceColombie-Britannique; Région extracotière de l'ouest
SNRC92C/14NE; 92F/03SE
Lat/Long OENS-125.2000 -125.1167 49.0833 48.9500
Sujetsdéglaciation; antecedents glaciaires; carottes; changements du niveau de la mer; variations du niveau de la mer; porosité; Holocène; Pléistocène; paléoclimats; 9; paléontologie; géologie marine; Nature et environnement; Quaternaire; Cénozoïque
Illustrationsstratigraphic columns; core logs; photographs; tables
ProgrammeGéosciences de changements climatiques, Études paléo-environnementales sur les changements climatiques
Diffusé2009 05 29
Résumé(disponible en anglais seulement)
The sedimentary record of Effingham Inlet, British Columbia, Canada (Appendix 1) is contained in: a 40.9 m giant (Calypso) piston core (MD02-2494; 49° 04.28 N/ 125° 09.55 W) raised from 120 m water depth in the inner basin, in June 2002, during the 2002 MONA (Marges Ouest Nord Américaines) campaign aboard the French ship RV Mariane Dufresne, and in four Geological Survey of Canada freeze cores (TUL99B04,VEC007-FC01, VEC007-FC02 and VEC007-FC03) which contain the surface sediments and were also raised from 120 m water depth in the inner basin in October, 1999, and April, 2005, from the CCGS John P. Tully, and the CCGS Vector . The piston core MD02-2494, spans from 14,000 14C yr BP (16,700 cal yr BP) to about nine centuries before present, and the freeze cores represent from ~ AD 1992 to ~ 850 y BP.

These cores archive changes in sedimentation (Table 1)(Appendix 1 and 2) and relative sea-level immediately following deglaciation of the Late Wisconsin Fraser Glaciation, which peaked about 15,000 14C yr BP. The presence of the Mazama Ash in the MD02-2494 piston core, anchors a detailed chronology (Fig. 1) based on forty-nine radiocarbon dates and seven Pleistocene paleo-magnetic secular variation correlations. Diatom assemblages (Table 2) identify a marine-freshwater transition in the basin, which occurred 11,631 14C yr BP (13,503 cal yr BP). At this time a bedrock sill, presently at 46 m depth, was briefly exposed as sea-level fell. The relative sea level rose again during isostatic crustal adjustments, with a brackish-freshwater-full marine transition at 9,851 14C yr BP (11,165 cal yr BP). These data constrain a new sea-level curve for the outer coast of Vancouver Island covering the past 12,000 14C yr BP (14,000 cal y BP) providing new information on the nature of deglaciation along the west coast of Canada, and informing interpretations of regional paleoceanographic records, and mantle viscosity models.