Landforms of erosion

Cliffs/Wave cut notches/platforms

Headlands and Bays

Caves, Blowholes, Arches, Stacks and Stumps

When the waves undercut the cliff

A wave-cut notch develops into a cave, the overhanging cliff is no longer supported casuing the cliff to collapse. This happens repeatedly and the layer of flat rock left is the wave cut platform.

Less than 4 degrees.

The wave-cut platform decreases the rate of erosion, as the waves have further to travel to the base of the cliff. The wave energy also disserpates over the platform, reducing the amount of erosion occuring.

A discordant coastline occurs where bands of different rock type run perpendicular to the coast. 

A concordant coastline occurs where beds, or layers, of differing rock types are folded into ridges that run parallel to the coast.

Discordant coastline

Concordant coastline

As waves approach a coast they are refracted so that their energy is concentrated around headlands but reduced around bays. Waves then tend to approach coastline parallel to it, and their energy decreases as water depth decreases.

Hydraulic Action

Attriction

Solution

Abraision

When the waves erode the cliff, the softer rock gets eroded faster as it is less resistant. This means that the hard rock sticks out to sea - this is called a headland. The sheltered area between the headland is called a bay- this is where a beach is formed.

When waves erode the cliff it causes cracks. Due to the erosional processes, such as hydraulic action, air trapped in the cracks gets compressed by the force of the waves against the cliff causing more erosion to take place. As the crack crumbles and erodes further into the rock it forms a cave.

An arch is formed when a cave gets eroded through to the other side of the cliff.

Occasionally,wave action and weathering erodes joints in the cave roof to form a blow hole. Where the cave erodes through the headland an arch is formed.

A stack is formed when the roof of an arch collapses.

A stump is a collapsed stack.

Alternatiting rate of erosion of hard and soft rock

Discordant coastline

Repeated process of cliff collapsing after a cliff can no longer support the overhand of cliff because of the formation of a wave-cut notch.

Embryo dune

Yellow dune

Foredune

Dune slack

Dune heath

Saltation

Lyme grass, marram grass and sand couch

Dune heath

To catch and trap the sand, so it build up to become a sand dune.

1. the organic component of soil, formed by the decomposition of leaves and other plant material by soil microorganisms.

20%

Spits are formed where the coast suddenly changes direction e.g. across a river mouth. Longshore drift continues to deposit material across the mouth of a river which results in the formation of a long bank of sand and shingle forming.

The sediment is carried out to sea in the backwash in the direction of the prevailing wind. The sediment is then brought back into shore at 90 degrees in the swash.

When a spit joins two headlands

A Lagoon

A spit that joins with an island

A saltmarsh

Halophytes - Pioneer plants

Landforms of deposition occur where accumulation of sand and shingle is greater than it is removed.

Constructive

Destructive

Cusps are crescent-shaped indentations  that form on beaches of mixed sand and shingle.

They are formed where there is a junction between sand and shingle

There are often a series of smaller ridges formed beneath the storm ridge known as berms.

Ridges and runnels  form parallel to the shore line in the foreshore zone. Ridges are areas of the foreshore that are raised above the adjacent shore which dips into a Runnel.