A review of sea level change during the Flandrian period concludes that a steady rather than oscillatory rise has occurred. In Britain the eustatic rise has been modified by isostatic effects; these are reflected in slightly different sea level curves for the Severn, Thames and Clyde estuaries. Higher undrained shear strengths recorded in the outer Thames estuary and taken to imply a transgressive/regressive sequence are inconclusive of an oscillatory curve; such desiccated horizons are not present in the Severn Levels.
The pattern of sea level rise is reflected in the nature of the sediment. The characteristics of a silty sand deposited during a period of rapid sea level rise and overlain by a laminated mud/silty sand sequence with occasional peat horizons are discussed. A proposed description for laminae thickness is presented. Bioturbation may modify the sediment character of tidal river environments.
Tidal pills, common in salt marsh areas, are difficult to detect when infilled. The geotechnical affects of the features are related to their different consolidation properties and skin friction compared with the normally deposited (layered) sediments. The importance of laminations in soils to lateral pore water dissipation and the implications for road embankment construction are considered.