CGRG Bibliography of Canadian Geomorphology
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Author : Carle, L.; and Hill, P.R.
Date : 2002.
Title : Morphology and sedimentology of the subtidal zone and upper slope of Roberts Bank (Fraser River Delta, British Columbia, Canada).
Publication : American Geophysical Union 2002 Fall Meeting, Moscone Center, San Francisco, California, 6-10 December 2002.
Issue :
Page(s) :
Abstract
The Fraser River delta that underlies suburbs of Vancouver has been subject to a significant reduction of sediment input due to dredging of the Main Channel. Subsidence and marine transgression increase the erosion risk to infrastructure such as the delta port, ferry terminal and submarine power cables located on Roberts Bank. This bank receives little direct sediment supply because fluvial sediments from the Main Channel are deflected northward by the Coriolis effect and by tidal asymmetry. New information on shallow water (3 to 100 m depth) sediment transport features on the delta slope of Roberts Banks has been obtained from high-resolution multibeam surveys. Depositional bedforms are grouped in complexes of large asymmetric 2-D dunes (sinuous crested and straight crested) and large asymmetric 3-D dunes (high relief and low relief). Transverse profiles of some dune fields show that these dunes are superimposed on larger, 500 meter-scale bedforms. The orientation and the shape of the dunes give an indication of the dominant transport process (tidal current, waves and wind driven currents). A map of sediment transport directions has been constructed from these data. These sediment transport features are superimposed on a slope that also shows evidence for considerable erosion by downslope gravity processes (turbidity currents, rotational slumping and creep).
Bibliography of Canadian Geomorphology