Coastal🏖

Question 1

Formation of cliff and wave cut platform

Answer 1

Waves attack the foot of a cliff through abrasion and hydraulic action. Over time this creates a wave cut notch. This continues and the cliff is left unsupported and collapses due to gravity. As a result this cliff retreats and increases in height. The gentle sloping expanse of retreating cliff is called a wave cut platform

Question 2

Formation of a cave, arch, stack, stump

Answer 2

Waves attack areas of weakness in the headland such as a joint or fault and create a crack by hydraulic action. The crack grows - a sea cave is formed in the headland and is deepened by hydraulic action and abrasion. Waves continue to erode the headland to form an arch. The waves erode the underside of the arch and the roof becomes too heavy and collapses due to gravity. The roof of the arch is also eroded by freeze thaw action and collapses. This area of headland that is cut off is called a stack. Waves eventually undercut the stack which causes it to collapse forming a stump

Question 3

Longshore drift

Answer 3

Longshore drift is the method by which waves approach the coastline and move sand and pebbles along the beach. The sand and pebbles are carried up the beach (swash) at the same angle and brought back down (backwash) at right angles. This results in a zig zag motion which carries sand and pebbles along a coastline

Question 4

Formation of sandspit and sandbar

Answer 4

Longshore drift moves material along the coast in a zig zag motion. When this material reaches a break in the coastline such as a river estuary or bay it will deposit material to form a long, narrow line of shingle called a sandspit. A saltmarsh forms behind a spit. If the sand spit reaches the other side of the headland it forms a sandbar. A lagoon forms behind the bar. If a spit grows out across the sea and joins an island it becomes a tombole.

Question 5

Formation of a headland and bay

Answer 5

A headland is an area of land that juts out to sea and is surrounded by sea on 3 sides. Headlands form in coastlines where there is hard rock and soft rock which cause differential erosion. Hard resistant rocks are more difficult to erode than soft rocks. Hard rock such as limestome forms headlands and soft rock such as clay forms bays. Softer rock can be eroded faster by hydraulic action and abrasion