4.3 C Flashcards
What are the different types of sedimentary transportation and how do they effect longshore drift
Saltation
Solution
Suspension
Traction
These methods of transport move materials and the prevailing winds push them onto the shore with swash and pull them off with a backwash
Explain the transport methods
Saltation- sediment is transported by bouncing around the sea large clumps are quite hard to move over a long period of time .
Solution- Minerals are dissolved in the water. They are then carried in a solution . This solution is not visible . The load can come from cliffs made from chalk.
Suspension - small particles e.g chalk are moved across the sea usually making the water cloudy .
Traction- pebbles are rolled across the sea bed
How is a spit formed
A spit is an extended stretch of beach material that projects out to sea and is joined to the mainland at one end. Spits are formed where the prevailing wind blows at an angle to the coastline, resulting in longshore drift.
How are bars formed
Bars are formed when Spits connect with other land forming a bar shape . Longshore drift is responsible as it extends the spits . The water at the back is trapped meaning that a lagoon is formed . Winds can blow and deposit materials into the bar creating dunes. The lagoon will eventually soak up and turn into a salty marsh and over time the marsh will have many ,materials deposited into it. Due to the formation sand banks are also formed .
How are beaches formed
Beaches are usually made up of eroded materials from rocks which been transported and clumped together . Constructive waves are responsible for this formation . The waves will push off eroded materials and will clump them together in shallow waters. A cross-section of a beach is called a beach profile. The shingle ridges often found towards the back of a beach are called berms.
Smaller materials are placed at the ends of the beach while the larger materials are usually clumped at the beginning of the formation . Waves that break the shoreline often leave sediment which also goes to the beach. This is called attrition.
The most common means of transport is salutation and us the process where fragments of materials are bumped about each other until they reach the larger mass of sand .
What are the natural and human processes going on in swanage bay
Human. Natrual
Durslton bay. Minimal defences. Mass movement
And costal erosion
Swanage bay south Well defended Costal erosion deposition
Swanage bay north. Unprotected Some erosion of hard
Lime stone cliffs
Explain why discordant coastlines erode at a faster rate than concordant coastlines.
They erode quicker as they have more of a variety of soft and hard rock meaning that the waves can erode it quicker than you could if you a concordant coast line
Give a step by step description on how a wave cut platform is formed
- The sea starts to erode the cliff at the base starting to create a notch
- As the notch widens the structure of the cliffs start to slowly weaken over time
- The cliff face collpapses and a wave cut platform is formed
Name and describe defences that humans use to preserve land and beaches .
Groynes- collect and prevent sediment from being pulled away slowing down the weathering of beaches.
Sea wall- this protects cliffs land and buildings from erosion however they are expensive to build, maintain and the wall will start to erode.
Describe the costal management in holderness
Holderness is located in the south of england and is one of the most vulnerable beaches to erosion . It retreats at a rate of 2 metres a year.
The reason why this is so much of a problem is that the beach is made of soft clay so it is extremely easy to erode .
The village of Mappleton is on top of holderness and the properties their are extremely vulnerable to floods.
In 1991hard engineering methods have been used to prevent flooding by placing rock armor around the city
