Physical landscapes in the UK Flashcards
What would you find in the upper course of a river?
Characteristics - small stream, erosion occurs, steep gradient, high velocity, lots of friction
Features - waterfalls, V-shaped valleys, gorges
What would you find in the middle course of a river?
Characteristics - highest velocity, erosion and deposition, shallower gradient, flat surrounding land
Features - Meanders, Ox-bow lakes
What would you find in the lower course of a river?
Characteristics - very wide, very shallow gradient, deposition, low velocity
Features - mud flats, deltas, U-shaped valleys, estuaries
What is erosion?
The wearing away of sediment along a river due to high velocity.
What types of erosion occurs at the coastline?
Corrasion - when destructive waves pick up material and hurl it at the base of a cliff (produces a wave-cut notch)
Abrasion - sandpaper effect - where smaller sediments wear away the base of a cliff or headland
Hydraulic power - waves with high energy collide with the cliff and wear away, leaving the cliff prone to weathering
Attrition - when waves cause rocks and pebbles to bump into each other to break apart, becoming smaller and more rounded
What is transportation?
The movement of material along a water source, such as the sea or a river.
What types of transportation occur at coasts?
Longshore drift - the movement of material along the coast
Traction - Large pebbles/boulders rolling across the sea bed usually from high energy destructive waves
Saltation - small stones, pebbles or silt bouncing along the sea bed, moved by both constructive and destructive waves
Suspension - fine particles of clay/sediment are suspended in the sea and transported by both types of waves
Solution - when material is dissolved and carried by the sea
What is deposition?
When material being transported by water is dropped due to a lack of energy.
Why and where does deposition occur at coastlines?
Deposition occurs when waves have lost energy, in other words when the swash is stronger than the backwash in constructive waves. It is likely to occur when: waves enter areas of shallow water, there is little wind, or the amount of material being transported is greater than the wave energy can transport.
What is wave crest?
The highest point of the wave
What is the wave trough?
The lowest point of the wave
What is the wavelength?
The horizontal distance between two crests or troughs
What is the wave height?
The vertical distance between the crest and trough of the wave
What is swash?
The forwards movement of a wave up the beach
What is backwash?
The backward movement of back into the sea when a wave breaks
What is fetch?
The length of water which the wind has blown over, affecting the size of the wave
What is a constructive wave?
Waves that build beaches. The wave breaks and carries material up the beach in its swash, and material is deposited as the backwash soaks into the sand.
Long wavelength, low frequency
What is a destructive wave
Waves that destroy beaches. High, short wavelength and are frequent. Weak swash and strong backwash, causing a loss of beach material
What are the examples of mass movement?
Sliding
Slumping
Rock falls
How does rock type affect formations?
As more resistant rock erode more slowly, they project into the sea as headlands
Less resistant rocks usually cause mass movement and formations of bays
What is a concordant coastline?
Rock beds run parallel to the edge of the sea
What is a discordant coastline?
Rock beds run perpendicular to edge of the sea
How do headlands and bays form?
Headlands form along discordant coastlines, meaning the soft rock is eroded faster, leaving a section of sand jutting out (headlands). The areas where the soft rock has eroded away next to the headland is a bay.
How do spits and bars form?
Longshore drift moves material along the beach. When there is a change in the shape of the coastline, sediment is deposited forming a long ridge of material called a spit. When the spit extends across the bay and joins two headlands together, it forms a bar, trapping a lagoon behind it.
