Coasts Flashcards
What is abrasion?
Process of rock and pebbles carried by the waves wearing away rocks as they are thrown against cliffs.
What is attrition ?
This happens when rocks and pebbles carried by the waves smash into each other, wearing each other away and gradually becoming smaller,rounder and smoother.
What is solution?
This is when chemicals in the seawater dissolve minerals in the rocks, causing them to break up.
What is hydraulic action ?
Sheer force of waves crashing against the cliffs. The power of the waves forces air into the cracks, compresses it and blows the rock apart as the pressure is released.
what is swash and backwash?
waves travelling to and from the beach/coast
How is a cliff and wave-cut platform formed?
Waves attack the foot of the cliff through abrasion and hydraulic action. Overtime this creates a wave-cut notch. As it gets bigger the cliff above is left unsupported and collapsed due to gravity.
This continues and the cliff retreats and increases in height. The gentle sloping expanse of the retreating cliff is called a wave-cut platform.
Describe the formation of headland and bays?
A headland is an area of land which juts out to sea and is surrounded by sea on three sides. Headlands form in coastlines where there are hard rocks and soft rocks which causes differential erosion. Hard-resistant rocks are more difficult to erode than softer rocks. Harder rock (e.g. Limestone) forms the headlands and the softer rock (e.g. Clay) is eroded back to form the bays. The softer rock is eroded faster by abrasion and hydraulic action.
Describe the formation of caves, arches, stacks and stumps ?
Once headlands and bays form, the headlands are then attacked by powerful waves.
The waves pound against all sides and erode first the weakest parts of the headland.
These are the places where the cliffs have cracks. By abrasion and hydraulic action the waves make the cracks wider.
In time, this weak area will be eroded more and more until a cave forms.
The waves now erode the sides and back of the cave until they reach the other side of the headland and the cave becomes an arch.
The rock around the bottom of the arch is now attacked by waves so that it becomes wider.
Meanwhile, the rocks above the arch become more unstable. Cracks appear and in time the rock collapses.
This leaves a pillar of rock separated from the headland, called a stack.
Over time, the waves pound against the stack and eventually it will collapse to form a stump.
Describe longshore drift?
Along many of our coastlines the swash travels up the beach at an angle due to prevailing winds.
As it has some energy it picks up sand and shingle and takes them up the beach.
But it doesn’t go back along the same route. Instead, the backwash returns to the sea down the steepest slope due to gravity.
The backwash carries the sand and shingle with it, which it deposits where it loses energy.
This results is a zig-zag motion along the beach.
Describe the formation of a sandpit ?
When the coastline changes direction, longshore drift will continue to transport sediment in the same direction as the original coastline.
This sediment is deposited in the open water and builds up new land over time.
A temporary change in the wind direction causes a spit to curve as it ends.
This area of water sheltered by the spit fills up with mud and forms into a ‘salt-marsh’.
Describe the formation of sandbars ?
A ‘bar’ is formed if deposition continues across a bay and joins up with a beach on the other side. Shallow, stagnant water, trapped behind the bars is called a ‘lagoon’.
Describe the formation of tombolos ?
A tombolo will form when a spit grows out into the open water and reaches an island. The island is then joined to the mainland by a tombolo.
Give examples of conflicts between tourists vs locals ? (7)
Increased traffic congestion on coastal roads, especially at peak times (1)
Prevents local people from going about their daily activities (1)
Air and noise pollution rises due to increased tourist cars(1)
Holiday/second home ownership increases(1) forcing some local people/first time buyers to move away (1) as they struggle to get on the property ladder.
Services may close as second home owners are not permanent residents(1)
Visitors leave litter on beaches such as Chesil beach(1)
Footpath erosion occurs in popular walking areas such as Studland(1)
Give examples of conflicts between tourists vs tourists ?(3)
Swimmers and sunbathers may be disturbed from the noise of motor boats and water sports.
Anglers e.g. At Chesil beach may be disturbed by activities such as water skiing
Camp and caravan sites spoil views for tourists.
Give examples of conflicts between tourists vs renewable energy ?(2)
Wind turbines spoil the natural beauty of the coastline in places such as Poole(1) and may put some tourists off visiting (1)
This could reduce the profits for local businesses that rely on tourism (1) and may lead to unemployment if tourists related services have to close(1)
