Coasts

Geography - Paper 1

How do waves form?

-Wind blowing over the sea

-Friction with the surface of the water causes ripples

-Tsunamis from natural hazards causing seabed to shake

What are constructive waves?

-Low waves

-Crests far apart

-Gently sloping wave front

-Constructs the beach

-Strong swash and weak backwash

What are destructive waves?

-Tall waves

-Crests close together

-Steep wave front

-Destroys the beach (creates a steep beach)

-Weak swash and strong backwash

What is weathering?

The decay or disintegration of rocks

Give the 3 types of weathering

-Physical (mechanical)

-Chemical

-Biological

What is physical (mechanical) weathering?

Freeze-thaw

What is chemical weathering?

Slightly acidic seawater/rainwater coming in contact with alkali rocks

What is biological weathering?

Plant roots growing and expanding in cracks of rocks or animals burrowing in rock cracks

What is freeze-thaw?

When rainwater collects in the cracks of rocks, it freezes and expands. It then melts again and freezes. This repeats many times till the crack expands so much that the rock breaks apart

What is mass movement?

The downward movement of material under gravities influence

Give 3 examples of mass movement

-Sliding

-Slumping

-Rockfalls

What is meant by sliding?

Blocks of rock slide down a cliff (due to rockfall or earthquakes)

What is meant by slumping?

The collapse of saturated or weak rocks along a curved surface

What is meant by rockfall?

Rocks breaking away often due to freeze-thaw weathering

What is erosion?

The wearing away of a landscape

What are the 4 types of erosion?

-Hydraulic action

-Abrasion

-Attrition

-Solution

What is meant by hydraulic action?

The power of the waves as they hit a cliff. The air is forced into cracks in the rocks, eventually causing it to break up

What is meant by abrasion?

The ‘sandpapering’ effect of pebbles being dragged over a rocky platform. The term corrasion usually involves fragments of rock picked up by the sea and hurled at a cliff

What is meant by attrition?

Rock fragments carried by the sea knock against each other becoming smaller and more rounded

What is deposition?

It is when sediment is deposited due to the loss of energy. This can be caused by shallow water or weak winds

What is transpiration?

Eroded material being transported

Give the 4 examples of transportation

-Traction

-Saltation

-Suspension

-Solution

What is meant by traction?

Large, heavy boulders rolling along the seabed

What is meant by saltation?

Small, heavy pebbles bouncing/hopping along the seabed

What is meant by suspension?

Small, light pebbles suspended within the water

What is meant by solution?

Dissolved chemicals often derived from limestone or chalk

What is longshore drift?

The movement of sediment depending of the direction of waves approaching the coast, as a result of the prevailing wind direction