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Coastal Landscapes

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Coastal Landscapes Introduction The sea, just like rivers and ice is a very powerful agent of erosion. It erodes a variety of landforms, and just like all agents of ... – PowerPoint PPT presentation

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Date added: 7 March 2019
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Title: Coastal Landscapes


1
Coastal Landscapes
  • Introduction

2
  • The sea, just like rivers and ice is a very
    powerful agent of erosion.
  • It erodes a variety of landforms, and just like
    all agents of erosion, it also transports the
    material it erodes and makes new landforms where
    it deposits this material.

3
Processes of coastal erosion
  • Waves that have a lot of energy are able to erode
    the land at the coast.
  • Waves erode the land by three main processes.
  • Hydraulic action, Corrasion and solution.

4
Hydraulic Action
  • This is the sheer power of the waves smashing
    against the cliffs, compressing the air in its
    cracks, which makes the cracks wider and longer
    until pieces of rock break off.

5
Corrasion
  • This is when the sand, shingle and pebbles that
    waves are carrying are hurled against the cliff,
    causing pieces of rock to eventually break off.
  • The rocks that break off the cliff and lie on the
    beach are then picked up by other waves and used
    to corrade the cliff even more.
  • The rocks themselves are broken up into smaller
    and more rounded pieces.

6
Solution
  • This occurs as salt and other chemicals in the
    sea water slowly dissolve minerals in the rocks,
    causing them to break up.

7
Processes of Coastal deposition
  • The coastline of the British isles is being worn
    away, but this does not mean that our land will
    eventually disappear.
  • The material that waves erode is deposited and
    builds up land elsewhere.

8
  • Waves deposit in areas where they have very
    little energy.
  • They deposit the largest particles first, so the
    material is sorted according to size.

9
Processes of coastal transportation
  • When a wave breaks near the shore and washes up
    the beach this is called swash.
  • When it runs back down the beach and back into
    the sea, it is called backwash.
  • Along many of our coastlines the swash travels up
    our beaches at an angle.

10
  • As it has some energy it picks up sand and
    shingle and takes them up the beach.
  • Backwash returns to sea down the steepest slope.
  • The backwash carries the sand and shingle with
    it.

11
  • The swash from the next wave then picks the same
    particles up and repeats the process.
  • In this zig-zag way sand and shingle are
    transported along the beach.
  • The process is called longshore drift and it
    takes place in the direction of the prevailing
    winds.

12
Longshore Drift
13
Questions
  • 1) Describe the 3 processes by which waves erode.
  • 2) Waves deposit sorted particles. What does
    this mean?
  • 3) What is the difference between swash and
    backwash?
  • 4) What name is given to the movement of sand
    along a beach?
  • 5) Using a diagram, explain how material is moved
    along a beach.
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