Coasts Flashcards
(23 cards)
What is a coast?
Where the land meets the sea. It is a dynamic zone.
What is coastal erosion?
The wearing away of the land by the sea.
What is hydraulic action?
The hammering of the waves breaking rock.
What is abrasion?
When pebbles and sand get flung against the rock, scraping and scouring it away.
What is attrition?
When rock fragments and pebbles are flung against each other, wearing each other away.
What is solution?
When the water dissolves some materials.
How is a a cave formed?
Over time when waves form cracks at the base of the headland and it becomes larger
How is a stack formed?
When the arch gets bigger and eventually collapses leaving a stack separated from the mainland
How is a stump formed?
When the stack erodes and becomes much smaller
What is longshore drift?
The movement of material along a coast by waves which approach at an angle to the shore but recede directly away from it.
What is the equation for finding out the wave angle?
tan^-1(longshore drift per min/ swash distance)
What is a spit?
An extended stretch of beach material that projects out to sea and is joined to the mainland at one end
What is suspension?
Small particles are carried in the water, e.g. silts and clays, which can make the water look cloudy. Currents pick up a large amounts of sediment in suspension during a storm, when strong winds generate high energy waves
What is saltation?
Load is bounced along the seabed, e.g. small pieces of shingle or large sand grains. Currents cannot keep the larger and heavier sediment afloat for long periods
What is traction?
Pebbles in largest sediment are rolled along the seabed
What is deposition?
When the sea loses energy, it drops the sand, rock particles and pebbles it has been carrying
When does deposition happen?
When the swash is stronger than the backwash and is associated with constructive waves
Where does deposition happen?
When the waves into an area of shallow water
When the waves into a sheltered area, e.g. a cove or bay
When there is little wind
When there is a good supply of material
What is a headland?
A section of land jutting out into the sea
What is a bay?
The areas where the softer rock has eroded away, next to the headland
How are headlands formed?
When the sea attacks a section of coast with alternating bands of hard and soft rock. The bands of soft rock, such as sand and clay, erode more quickly than those of more resistant rock, such as chalk
What are discordant coastlines?
Where the geology alternates between the bands of hard rock and softer rock
What is a concordant coastline?
The same type of rock along its length. These coastlines tend to have fewer bays and headlands
