Geoographyy😭

• Coast


  The area where the land meets the sea
• Sea


  A large body of saline water located on the margins of continents
• Ocean


  A large and extensive body of saline water occupying a basin between continents
• Waves


  Moving ridges of water on the sea
• Waves are formed when the wind blows over an open water body causing oscillation of water particles. The length of water the wind blows over is called its fetch. The stronger the wind is, the longer it blows for, and the longer the fetch, the larger the waves will be and the more energy they will have
• Parts of a wave

  • Crest
  • Trough
  • Wavelength
  • Height/Amplitude
• When a wave reaches the shore, the water particles below the surface start touching the ocean floor causing it to break. There is a forward movement of water to the beach which is called a swash/send. The water rushing up the sand is called the uprush. There is backward movement of water to the sea due to gravity called backwash. The rest flows at the bottom back into the sea in a water current called undertow
• Types of waves

  • Constructive waves
  • Destructive waves
• Tides


  Periodic rise and fall in the level of the ocean and other large water bodies
• Tides occur when the moon, and to some extent the sun, exert gravitational pull on the water bodies on the Earth
• Tidal phases


  • Low tide
  • High tide
• Tidal range


  Difference between the highest level reached by high tide and the lowest level reached by low tide
• Tidal range changes through the year because the pull on the sea changes as the moon orbits the Earth, and the Earth orbits the Sun
• Wave erosion

  1. Abrasion

  2. Corrasion

  3. Attrition

  4. Hydraulic action

  5. Solution

  6. Corrosion
• Abrasion involves the scratching of the ocean floor by materials (load) that are carried by the backwash
• Corrasion involves the hurling of pebbles and rock fragments against the rocks causing some particles to break off
• Attrition breaks down sediments into smaller sized particles, and the repeated collision blunts any of the particles’ sharp
• Erosion by abrasion


  Small fragments break away from the rock face
• Rocks quickly eroded by abrasion


  • Soft sedimentary rocks like chalk, mudstones, clays, unconsolidated materials like boulder clay
• Attrition


  Breaks down sediments into smaller sized particles, blunts sharp edges of particles, making sediments increasingly rounded
• Hydraulic action


  Removal of materials from the coast by the force of moving water
• Solution


  Soluble minerals in the rock dissolve directly in water and are carried away in solution form leaving cavities in the rocks
• Corrosion


  Rock minerals like limestone react with sea water containing dissolved carbonic acid, carried away in solution form
• Factors influencing wave erosion

  • Waves
  • Slope
  • Load
  • Amount of water in a wave
• Wave transportation

  Waves carry eroded materials away, some to the sea and some along the coastline
• Longshore drift


  Waves transport the load across the shoreline by breaking at an angle
• Factors influencing wave transportation

  • Strength of waves
  • Tides
  • Ocean currents
  • Gradient of the shore
  • Orientation of the coastline
  • Nature of load
• Wave deposition


  Materials transported by waves are laid down on the shore
• Factors influencing wave deposition

  • Load
  • Waves
  • Gradient of the shore
  • Depth of water
• Landforms created by waves

  • Cliff
  • Headland
  • Wave-cut platform
• Cliff is a steep rock face bordering the sea
• Headland is a piece of land jutting into the sea
• Big bay is called a gulf
• Wave-cut platform is a fairly flat part of the shore formed when a cliff retreats inland
• Platform


  A fairly flat part of the shore formed when a cliff retreats inland
• Formation of a platform


  1. Breaking waves erode the rock surface of a steep coast cutting a notch on it

  2. Erosion process continues causing the base of the rock to be undercut resulting in an overhanging rock

  3. Undercutting continues, causing the overhanging rock to collapse and form a cliff

  4. This process is repeated and a fairly flat part of the shore is formed between the new and a former cliff
• Bay


  A piece of sea water jutting into the land or a curved inlet of the sea
• Cave


  A natural cylindrical tunnel-like chamber that extends into the cliff or into the side of a headland
• Formation of a cave


  1. A small hollow forms on a weak area of the cliff after limestone is acted upon by carbonation

  2. Corrosion and direct dissolving of the minerals in the limestone erode the hollow, extending it into the cliff to form a cave
• Arch


  An opening from one side of a headland to the other