An Early Holocene Tidal Flat in the Southern Bight
bookPart
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.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. © 1981 The International Association of Sedimentologists.
Topics
TNO Identifier
533486
ISBN
9781444303759 ; 9780632008582
Publisher
Wiley Blackwell
Source title
Holocene Marine Sedimentation in the North Sea Basin
Pages
229-237
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