Shingle beach types

Shingle beaches are often highly mobile foreshores, regularly washed by waves and sea water spray where storm waves can influence the stability of the beach above normal high tide levels. They generally support only limited, ephemeral vegetation. Three basic types are described:

1. the simplest and commonest type of shingle habitat is the fringing beach forming a strip in contact with the land along the top of the beach;
2. shingle spits form where there is an abrupt change in the direction of the coast. They often contain recurved hooks and a recurved distal end, a result of deflection of waves by refraction. This recurvature may also be caused by waves approaching from two directions;
3. bars or barriers are effectively spits, which have formed across estuary mouths or indentations in the coast. Ecologically bars differ from spits in having a less maritime environment to their lee (Kidson 1963).

Comment: Some shingle spits, bars and barriers may become substantial structures when large quantities of shingle are available for their development. However, under the definitions used here they tend to be exposed to oceanic influences due to their relative narrowness. This tends to limit the type and density of plant cover, though important maritime communities with abundant lichens can develop.

References

Kidson, C. 1963. The growth of sand and shingle spits across estuaries. Zeitschrift fur Geomorphologie, 7., 1-22.