coasts- geography aqa gcse

Waves are caused by the transfer of energy from the wind to the sea due to friction ov the wind on the waters surface

Strong winds result in stronger waves because more energy is being transferred to the waves

The longer the wind has been blowing, the more energy is transferred and the stronger the wave

The maximum distance of open sea that a wind can blow over. A longer fetch gives a greater possibility for larger waves.

1. Strong swash, weak backwash. 2. Low waveheight, long wavelength. 3. Low frequency. 4. Deposistional- build up the beach

1. Weak swash, strong backwash. 2. High wave height, small wavelength 3. High frequency 4. Erosional- wear away beaches

Flow of water up a beach

Movement of water down a beach due to gravity

Maximum distance of open sea that a wind can blow over

Top of a wave

Base of a wave

Number of waves breaking per minute

Caused by a chemical reaction when rainwater hits the rock and decomposes or eats away at it

Usually associated with extremes of temperature, results in rocks being disintergrated rather than decomposed

The downward movement of rock, soil or mud under the influence of gravity.

Rocks are broken down by oxygen and water

Acidic rainwater breaks down the rock, causing it to rot

Carbonic acid in rainwater reacts with calcium carbonate in limestone to form calcium bicarbonate. This is soluble, so limestone is carried away in solution.

1. Water enters cracks in rocks 2. At night the temperature drops below 0 degrees 3. The water freezes and expands by 9-10% 4. This puts pressure on the cracks 5. If the temperature goes above freezing, the ice will thaw 6. Repeated diurnal freezing and thawing causes fragments to break off

Salt spray gets into cracks. It may evaporate and crystallise, putting pressre on the surrounding rock and weakening the structure.

Rocks lose contact with the cliff face. Fall due to gravity. Fan out at the bottom to form scree scopes.

Donward movement of material down a slope. Aided by weathering and heavy rainfall. (Makes cliff heavier and lubricated). Occur quickly. Where vegetation is sparse.

Similar to a slide. However, instead of moving straight down a cliff, there is a concave slip plane.

The force of water getting into cracks in rocks and breaking them apart under pressure.

Rocks in the water being thrown against the cliff face and wearing it away.

Rocks crashing into each other and gradually getting smaller and smoother.

Where sea water dissolves certain rock types. (chalk and limestone)

When the sea loses its energy it drops any material it was carrying.

1. Waves starting to slow down and lose energy 2. shallow water 3. Sheltered areas 4. Little or no wind

Large particles such as boulders roll along the sea floor

Pebble sized particles are bounced along the sea bed

Small particles such as silt and clay are carried along in the water

Soluble materials dissolve in the sea water and are carried along

The prevailing wind causes waves to approach the coast at an angle. The swash carries the sand and pebbles up the beach at the same angle, usually 45 degrees. The backwash, however carries the material back down the beach at right angles as this is the steepest gradient. If a pebble was placed in the water it would be carried along the coastline in a zig-zag motion and would eventually be deposited when the wave loses energy.

A cliff that juts out into the sea. It is surrounded by water on three sides. Normally composed of hard rock. High energy areas. Example- Durlston head.

Crescent shaped indentation, found between 2 headlands. It usually has a beach. Low energy enviroments. Example- Swanage bay

Hard rock, tall, steep, vertical notches at the bottom. The rate of collapse and erosion depends on harness of rock. Example- Burton Bradstock

An almost flat area of bedrock visible at the base of some cliffs. Slopes very gently to sea. Visible at low tide. Example- Washing ledge at Kimmeridge bay

Can be meters high and taper back a long way. Found at headlands and in cliffs. Example- In limestone cliffs at Durlston head

Unsupported top, wavecut notch at the base, water going through gap, often an extension of the headland. Example- Durdle door

Detached blocks or pillars of rock, loacted off headlands, often several meters high, hard rock. Example- Old harry rocks

The base of collapsed stacks, do lower in eight and only seen at low tide. Example- Old harry’s wife

1. Wave types- Constructive build beaches, destructive remove sediment 2. Tides- At high tide the effect will be higher up the beach. 3. Time of year- Winter has more storms so destructive waves are more common. In summer constructive waves rebuild beaches.