An introduction

to coasts

What is the difference between weathering and erosion?

Weathering is the wearing away of rocks.

Erosion is when the loose material is transported away.

1. Biological weathering

Caused by the action of plants on rocks.

Example………………

2. Mechanical weathering

Caused by changes in temperature. The rocks expand in the heat and contract in the cold.

Example……………………

3. Chemical weathering

Caused by the action of water on chemicals in the rock.

Example……………..

ErosionErosion is the movement of particles by wind, water, ice or people.

Coastal Processes

Like rivers there are 3 main things that coasts can do:

1. They erode material2. Then they transport material 3. And finally they deposit material

Why study coastlines?

• Coasts can produce beautiful landforms through the processes of erosion and deposition. Some of our best natural wonders were made this way.

• Coastal areas can erode and flood. We need to understand their processes so we know the most effective ways to manage them.

COASTAL EROSION

• http://blip.tv/gatm/sticky-coastal-erosion-940748

What are the processes of erosion along a coastline?

The same 4 processes of erosion that are at work on rivers also apply to coasts.

• Hydraulic action: The force of the water causes cracks in the cliffs and material gradually breaks off.

• Abrasion: Bits of rock and sand in waves grind down cliff surfaces like sandpaper.

• Attrition: Waves smash rocks and pebbles on the shore into each other, and they break and become smoother.

• Solution: Acids contained in sea water will dissolve some types of rock such as chalk or limestone.

Old Harry

Old Harry and his wife!