Coasts Flashcards
Define weathering
The process of rocks and artificial structures getting worn away into smaller pieces
What are the 3 types of weathering
Physical/mechanical
Biological
Chemical
Describe physical weathering
Rain water gets into cracks, freezes into ice and expands causing the rock to crack - freeze thaw
Sun heats rocks which expand in the heat, at night they contract - causing stress -Onion Skin weathering
What is biological weathering
Rocks are broken apart by growing tree roots and plants getting into cracks
What is chemical weathering
Not a mechanical process
All rain is slightly acidic and the acid reacts with the stone wearing it away/
Sulphur dioxide can make rain more acidic
How are waves formed
Waves are caused by wind dragging on the surface of the water.
The length of water the wind blows on is called the fetch.
The stronger the wind, longer it blows for and longer the fetch - the larger the waves will be and more energy they will have.
Describe constructive waves
Long + low
Less powerful
Deposit material - build beaches
6-8 per minuet
WHEN SWASH IS STRONGER THAN BACKWASH
Describe destructive waves
Strong winds Short and steep Remove material from beach 15 per minuet BACKWASH IS STRONGER THAN SWASH
Define erosion
The geological process in which materials are worn away and transported by natural forces such as wind or water. The opposite to deposition
What is the difference between weathering and erosion
Erosion involves movement and weathering is static
What is Hydraulic action
The power of the waves that smash against the rocks. Water enters cracks which then forces them to break apart
What is Abrasion
The process of wearing something away, the rocks grind away at the sea bed or beach
What is Attrition
Rocks in the backwash smash against each other. They break apart becoming smaller and more rounded
What is corrosion
Where the sea water dissolves certain types of rock
Define transportation
The movement of sediment within the sea by waves
Give the 4 types of transportation
Solution
Saltation
Suspension
Traction
Describe Traction
Pebbles and large sediment are rolled along the seabed
Describe Suspension
Small particles are carried in the water e.g sand and clays, which can make the water look cloudy. Currents pick up large amounts of sediment in suspension during a storm, when strong winds generate high energy waves
What is solution
Minerals are dissolved in the sea water and are carried in solution. The load is therefore not visible. Load can come from cliffs made of chalk or limestone and calcium carbonate is carried along in solution