Predicted Sand-Wave Formation and Decay on a Large Offshore Tidal-Current Sand-Sheet

  1. S.-D. Nio,
  2. R. T. E. Shüttenhelm and
  3. Tj. C. E. Van Weering
  1. Michael A. Johnson,
  2. Arthur H. Stride,
  3. Robert H. Belderson and
  4. Neil H. Kenyon

Published Online: 29 JUN 2009

DOI: 10.1002/9781444303759.ch19

Holocene Marine Sedimentation in the North Sea Basin

Holocene Marine Sedimentation in the North Sea Basin

How to Cite

Johnson, M. A., Stride, A. H., Belderson, R. H. and Kenyon, N. H. (1981) Predicted Sand-Wave Formation and Decay on a Large Offshore Tidal-Current Sand-Sheet, in Holocene Marine Sedimentation in the North Sea Basin (eds S.-D. Nio, R. T. E. Shüttenhelm and Tj. C. E. Van Weering), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444303759.ch19

Author Information

  1. Institute of Oceanographic Sciences, Wormley, Godalming, Surrey, UK

Publication History

  1. Published Online: 29 JUN 2009
  2. Published Print: 23 DEC 1981

ISBN Information

Print ISBN: 9780632008582

Online ISBN: 9781444303759

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Keywords:

  • small sand-waves (rather than sand-ripples) in flumes;
  • sand-waves fluid viscosity;
  • sand-wave formation and decay;
  • storm-wave incidence and unidirectional current contributions;
  • near-bed oscillatory water speeds

Summary

The conditions required for generation of small sand-waves (rather than sand-ripples) in flumes have been applied to the extensive field of sand-waves, occurring on a depositional sand-sheet in the Southern Bight of the North Sea, for mean spring tides and extreme spring tides at both summer and winter water temperatures and viscosities. The variation in the position of the predicted boundaries of sand-wave formation (from an initially rippled bed) is striking. The tidal currents at near-minimum winter water temperatures would be unable (on their own) to generate sand-waves on almost any part of the sand-sheet. At near-maximum summer water temperatures the tidal currents of mean springs would (on their own) generate sand-waves up to 40 km further across the sand-sheet, and very extreme spring tides to a still further distance of about 40 km. Smaller boundary migrations would be predicted for the combined action of the tidal and non-tidal currents. Across a large part of the sand-sheet the small sand-waves are active over a long enough period to have grown into large sand-waves (with small ones on them). However, in an outer zone the small sand-waves will be largely flattened by bioturbation and storm waves during periods of weak tidal currents, and so will not be able to develop into large ones.

The overall form, grain size and internal structure of the sand-sheet will reflect both the periodic and episodic building and destruction of the small sand-waves in the outer zone, the presence and variability of smaller on larger sand-waves in the inner zone, and the geographical differences in the shape of the large sand-waves.