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TitreSedimentation rates and patterns on a deep-water delta (Fraser Delta, Canada): integration of high-resolution seismic stratigraphy, core lithofacies, and 137Cs fallout stratigraphy
AuteurHart, B S; Hamilton, T S; Barrie, J V
SourceJournal of Sedimentary Research vol. 68, no. 4, 1998 p. 556-568,
Séries alt.Commission géologique du Canada, Contributions aux publications extérieures 1998012
ÉditeurSociety for Sedimentary Geology
Documentpublication en série
Mediapapier; en ligne; numérique
SNRC92B; 92G
Lat/Long OENS-123.6667 -123.0000 49.3667 48.8333
SujetsHolocène; deltas; débit de sedimentation; talus continental; systèmes fluviaux; réseaux de circulation de l'eau; régions extracôtières; taux de décharge; milieux marins; géologie marine; sédimentologie
Illustrationslocation maps; graphs; seismic profiles; stratigraphic columns
Résumé(disponible en anglais seulement)
The Fraser Delta is a Holocene feature with complex surficial geology that has built into the deep (>300 m) water of the Strait of Georgia on Canada's west coast. We used high-resolution marine geophysical data, core lithofacies, and fallout stratigraphy to examine modern sedimentation rates on the delta slope and prodelta. Modern sedimentation rates, measured by the peak and onset of 137Cs in cores, are in excess of 13 cm yr-1 near the mouth of the main fluvial distributary but drop to less than 3 cm yr-1 farther than 4 km offshore. Asymmetry to the pattern of sedimentation rates reflects both the prevailing oceanographic circulation and human influence. The map of modern sedimentation provides a synoptic view of this deltaic system that is of value to understanding older deltaic systems as well as the modern offshore environments on this populous and heavily used delta. In attempting to estimate the annual sediment discharge of the river from our sedimentation-rate map, we were able to account for slightly less than 40% of the measured river discharge. Our inability to adequately characterize the deposition and resedimentation of the sand fraction is probably responsible for most of the discrepancy.