Coastal Landforms of Erosion

Erosion: Key Terms

• Stick the sheet in – avoid any confusion!

Attrition

Material carried by the waves bump into each other and so are smoothed and broken down into smaller particles.

Corrasion

This is the process by which the coast is worn down by material carried by the waves. Waves throw these particles against the rock, sometimes at high velocity.

Hydraulic action

This process involves the force of water against the coast. The waves enter cracks (faults) in the coastline and compress the air within the crack. When the wave retreats, the air in the crack expands quickly causing a minor explosion. This process is repeated continuously.

Solution

This is the chemical action of sea water. The acids in the salt water slowly dissolve rocks on the coast. Limestone and chalk are particularly prone to this process.

Attrition

Hydraulic action

Corrasion / Abrasion

Corrosion

Processes of erosion

Processes of erosion

Coastal EROSION landformsvideo here

1) HEADLANDS AND BAYS

Headlands and bays

Headlands and bays

Why have the bays been eroded more than the headlands?Why are headlands now more vulnerable to erosion than bays?How do headlands protect bays from erosion?

Bay and Headland

1. Headlands and Bays Headlands and Bays form along coasts which have

alternating ______ of ____ and soft rock. The ______ of the coast is the most important factor controlling the _____ of the coast.

Headland = where ____ land projects out into the sea, usually with steep _____ .

Bay = low land, between the __________ , where the coast has ____________. Usually has a ______.

Retreated Cliffs High headlands geology shape hard bands

beach

2) Cliffs and wave cut platforms

How are cliffs and wave-cut platforms formed?

Wave cut platform formed between the high and low tides as the waves only attack the cliff and pass over the platform

2) Cliffs and wave cut platforms• Waves ____ the base of the cliff to form a

_____ ___ ______ and then over time the cliff ________ due to lack of support and _______ . As most of the cliff gets washed out to sea a _______ is left in its place, a wave cut platform. It is often _______ due to abrasion.

• platform gravity Erode collapses wave cut notch smooth

3) Caves, Arches, Stacks and Stumps

Caves, Arches, Stacks and stumps

What will happen to the part of the cliff labeled A

A

Formation of Arches, Stacks and Stumps

Exposed lines of weakness in the ______ allow Hydraulic Action to form small _____ along the base of the cliff. Over time the cave will continue to grow through _______ ______ and meet another cave on the other side of the headland forming a small ______ . ______ will continue and undercut the base of the arch until it eventually falls due to lack of support and _______. This leaves behind a stack which will eventually collapse due to ___________ and gravity to leave a _____.

erosion stump undercutting gravity

caves Hydraulic Action arch cliffs

Use the play doh to explain the formation of arches, stacks, stumps

BINGO!Key words:

Erosion Long shore drift

Corrasion AttritionSolution Hydraulic Action Constructive DestructiveSwash BackwashNotch CaveArch StackStump Headland