TEST OF PRACTICAL KNOWLEDGE QUESTION (a) List the features of coastal erosion (b) With the aid of diagrams, describe the characteristics and mode of formati...

Answer Details

(a) Features of coastal erosion

1. Cliffs.
2. Wave-cut platforms (abrasion platforms).
3. Caves, arches and stacks.
4. Headlands and bays.
5. Geos and blow-holes.

(b) The beach

Characteristics: A beach is a gently sloping accumulation of sand, pebbles and shingle deposited by waves along the shore between the low-water and high-water marks. It is a depositional (constructive) feature, usually curved and widest in sheltered bays, with the finer sand near the water and coarser shingle towards the back.

Mode of formation:

1. Waves carry large amounts of eroded material (sand, shingle and pebbles) obtained from cliffs and from the sea bed.
2. When constructive waves reach a gently sloping shore, their swash (up-rush) is strong and their backwash (return flow) is weak.
3. The strong swash pushes the load up the shore, but the weak backwash cannot drag all of it back, so material is left behind.
4. Repeated deposition of this material over time builds up the ridge of sand and shingle that forms the beach, especially in sheltered bays where wave energy is low.

A labelled diagram should show the sloping shore, the swash and backwash arrows, the deposited sand and shingle, and the high- and low-water marks.