Geoscience Reference
In-Depth Information
of it. In this respect, and because the material forms such a clear ridge, it may be that
the Cromer Ridge is the remains of a moraine similar to those found at the fronts of
many present-day glaciers and ice sheets.
The coastal scenery of northeast Norfolk consists of a narrow beach backed by
cliffs, varying in height from a few metres in some places to over 70 m just east of
Cromer. The cliffs are made of soft, clayey sediments, consisting sometimes of ice-laid
material and sometimes of Late Tertiary Crag sands, muds and gravels.
When attacked by waves, these soft cliffs slump and slide down onto the beach
before being washed away by storms. This contrasts with the much older and harder
bedrock cliffs seen at Hunstanton, which collapse as large, hard blocks. More dramatic,
however, is the contrast between these soft cliffs and the landscape of wide beaches,
beach-barriers and salt marshes of the northern coast. The beach-barriers are continu-
ally being built up with new material brought in by the sea, whereas the cliffs of the
northeast undergo a general regime of erosion and removal (Fig. 311).
Why is there this important change in the type of coastline around Norfolk? It may
be that the facing direction of the northeast coast exposes it to more vigorous storm
waves, or perhaps the shallowness of the offshore area of northern Norfolk removes
energy from the waves, reducing their erosive power.
FIG
310.
Looking northwestwards towards Overstrand (Fig. 294,
d5
) and Cromer (
d2
).
(Copyright reserved Cambridge University Collection of Air Photographs)
The east-facing coastline of south Norfolk and north Suffolk has a continuous,
narrow beach zone along its length which is locally backed by cliffs. These cliffs,
though made of the same ice-laid material as those in the northeast of Norfolk, are
rarely greater than 10 m in height. This stretch of coastline is under a general regime
of erosion by the sea, similar to that of northeast Norfolk. In this case, however, the
sea has not only removed sand and gravel material from the coastline but it has then
churned it up and dumped it back on the land to produce local exceptions to the regime,
where sediment has built up.
