Morphology and Sedimentary Processes on the Subaqueous Noeick River Delta, British Columbia, Canada
- Albina Colella3 and
- David B. Prior4
Published Online: 2 APR 2009
Copyright © 1990 The International Association of Sedimentologists
How to Cite
Bornhold, B. D. and Prior, D. B. (1990) Morphology and Sedimentary Processes on the Subaqueous Noeick River Delta, British Columbia, Canada, in Coarse-Grained Deltas (eds A. Colella and D. B. Prior), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444303858.ch9
Universita della Calabria, Italy
Atlantic Geoscience Center, Nova Scotia, Canada
- Published Online: 2 APR 2009
- Published Print: 19 OCT 1990
Print ISBN: 9780632028948
Online ISBN: 9781444303858
- morphology and sedimentary processes;
- subaqueous slope morphology;
- upper delta slope;
- Noeick River delta;
- seafloor morphologies;
- sediment-distribution patterns
The Noeick River has deposited a large fan delta along the sidewall of South Bentinck Arm, a fjord on the central British Columbia coast. The intertidal and supratidal delta has an area of about 8 × 105 m2; the underwater delta-front gradient averages 4–5° to water depths of 220 m, about 2 km from shore.
The Noeick River drains a high-relief basin of which 15% is covered by glaciers. In addition to large, annual floods related to snow- and icemelt, the river has experienced jokulhlaups, glacier outburst floods, the most recent of which were in October 1984 and August 1986. The floods caused major changes in the subaerial delta, including relocation of distributaries and the delivery of large quantities of coarse sediment, trees and other organic debris to the delta and adjacent inlet.
Side-scan sonar imagery and seismic profiling on the subaqueous delta revealed a suite of morphological features and sediment distribution patterns indicative of high-energy sediment-transport processes and little evidence of in situ slope failure. Seaward of the main subaerial distributary channel, radiating chutes and swales containing sand and gravel lead towards deeper water. Between 120 m and 170 m water depth, flutes, commonly aligned downslope, dominate the subaqueous delta. Further downslope, there is an extensive area of transverse symmetrical bedforms, 2–5 m high with wavelengths of 50–120 m, interpreted as antidunes. Sediments on the subaqueous delta front consist of interstratified organic-rich sandy muds and gravelly sands.