An Early Holocene Tidal Flat in the Southern Bight

  1. S.-D. Nio,
  2. R. T. E. Shüttenhelm and
  3. Tj. C. E. Van Weering
  1. D. Eisma1,
  2. W. G. Mook2 and
  3. C. Laban3

Published Online: 29 JUN 2009

DOI: 10.1002/9781444303759.ch17

Holocene Marine Sedimentation in the North Sea Basin

Holocene Marine Sedimentation in the North Sea Basin

How to Cite

Eisma, D., Mook, W. G. and Laban, C. (1981) An Early Holocene Tidal Flat in the Southern Bight, 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.ch17

Author Information

  1. 1

    Netherlands Institute for Sea Research, Texel, the Netherlands

  2. 2

    Physical Laboratory, State University, Groningen, the Netherlands

  3. 3

    Geological Survey of the Netherlands, Haarlem, the Netherlands

Publication History

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

ISBN Information

Print ISBN: 9780632008582

Online ISBN: 9781444303759



  • dead shells of molluscs;
  • Holocene tidal flat;
  • fossil Eocene and Plio-Pleistocene mollusc shells;
  • acoustical reflector from overlying younger Holocene sands;
  • Eocene and Plio-Pleistocene fossils


Salinity, temperature and age have been determined for Cardium edule shells, collected in the Southern Bight of the North Sea, from their isotopic composition. The results indicate that before c. 8100 BP (probably between c. 10,000 and 8000 BP) a brackish-water tidal-flat area existed in the present Deep Water Channel (chlorinity c. 13‰). Between c. 8000 and 7000 BP most of the Southern Bight was a tidal flat, and after c. 7000 BP most became fully marine, except for the Thames estuary (which remained an estuary) and an area off the southern Dutch coast that remained brackish until after 6000 BP (probably up to c. 5500 BP). The data for the Cardium edule shells are in agreement with the curve of sea-level rise in the Southern North Sea, except for two samples. The chlorinity distribution in the Southern Bight between c 9300 and 5900 BP clearly shows the influence of the freshwater outflow of the Rhine and Meuse. The growth-temperatures indicate that Cardium edule populations have been able to adapt themselves to the prevailing temperature conditions. The sharp increase in yearly average air temperatures in Central England between c. 10,000 and 7000 BP coincides with the period during which the Southern Bight was flooded and warm water from the south could reach the Southern North Sea. The Cardeum edule shells were transported to some extent but transport occurred only over relatively short distances: the present distribution of the early Holocene Cardium edule shells largely reflects the conditions of 9300–6000 years ago.