Physical landscapes in the UK Flashcards
What causes a wave ?
A transfer of energy from the wind to the sea due to friction of the wind on the water’s surface.
Features of a constructive wave
- Build up beaches
- Longer wavelenght
- Low wave frequency
- Waves not very tall
- Creates wide gently sloping beach
- Strong swash
- Weak backwash
Features of destructive waves
- Erodes beaches
- Weak swash
- Strong backwash
- Shorter wave length
- High wave frequency
- Taller waves
- Creates steep, narrow beach
What are the 4 types of erosion ?
- Abrasion (sediment scrapes against rockface)
- Attrition ( rocks & pebbles hit eachother)
- Hyrdraulic action (air forced into cracks)
- Soloution (Acidic seawater errodes limestone)
What is the order of erosional landforms ?
Crack, Cave, Arch, Stack, Stump
What is the case study for erosional landforms ?
Old Harry rocks , Studland - Poole
What is swash ?
Water rushing up the beach
Which waves are associated with costal errosion ?
Destructive waves
What is backwash ?
Water draining back down the beach
What is weathering ?
Weathering is the breakdown of rock at or near the surface by water.
What are the main 2 types of weathering ?
Mechanical weathering ( Freeze thaw)
Chemical weathering ( acid rain )
What is mass movement ?
When rocks loosened by weathring move down a slope under gravity.
What is slumping ?
When the clay becomes saturated during heavy rain and oozes down towards the sea.
What is sliding ?
When large chunks slide down slope quickly without any warning
What is rockfall ?
Where material breaks off the cliff and falls down the slope.
How is sediment transported along the coastline ?
Longshore drift
How does longshore drift work ?
1) Waves hit the beach at an angle determined by prevailing winds
2) Waves push sediment in this direction and up the beach in the swash
3) Due to gravity the wave carries sediment back down the beach in the backwash
4) This moves sediment along the beach
What is deposition ?
When the sea looses energy , it drops the sand, rock particles and pebbles that it has been carrying.
How do headlands and bays form ?
Where coasts are made from alternating bands of hard and soft rocks, destructive waves will erode the less resistant (softer rock) more to form bays and coves. The more resistant (harder) rocks sticks out into the sea to form headlands.
What is the fetch of a wave ?
The length of water over which the wind has travelled
What is beach nourishment?
The addition of sand & sediment to an eroding beach by humans.
What is a groyne ?
A low - lying concrete or wooden barrier constructed perpendicular to the seafront and run out to sea. They trap sediment being moved by long shore drift.
What is impermeable rock ?
A rock that water cannot pass through.
What is permeable rock ?
A rock which allows water to pass through it.
