Distinctive Landscapes

• Formation of a spit

  1. Prevailing wind pushes constructive waves at an angle up and down the beach, moving material through longshore drift
  2. Longshore drifts continues to the end of the mainland
  3. A change in direction of the coastline leads to sediment being deposited, building an extension of the land into sea
  4. Secondary winds cause sediment deposition to occur at a different angle, forming a recurved hook
• What is a beach?

  An area of accumulated sand, pebbles, stone or gravel deposited along a shore by the action of waves
• Formation of a beach

  1. Constructive waves deposit material through the strong swash
  2. Weak backwash moves little sediment back to sea
  3. Over time material builds up to form a beach. Smallest material is deposited nearer to the water by weak backwash from destructive waves, while larger sediment is at the back of the beach due to high-energy storm waves carrying large sediment
• Formation of a v-shaped valley

  1. Vertical erosion by hydraulic action, abrasion and solution occurs, deepening the valley
  2. As the river erodes downwards, the sides of the valley are exposed to freeze-thaw weathering, loosening the rocks and steepening the valley sides
  3. Over time, rocks break off the valley sides through mass movement and the material is transported further downstream by the river
  4. If there are areas of more resistant rock, the river will bend around them, creating interlocking spurs
• Formation of meanders

  1. Water flows fastest on the outside bend (thalweg), Causing more erosion through hydraulic action and abrasion
  2. The erosion undercuts the river bank, forming a river cliff
  3. River flows slower on the inside bend as there is more friction.
  4. Deposition occurs forming a slip off slope on the inside bend
• Formation of an oxbow lake

  1. Erosion and deposition continues, increasing the size of the meander
  2. The river current erodes the meander neck through lateral erosion, causing it to get narrower
  3. When it floods, the river cuts across the neck, taking the shorter and straighter route
  4. The flow of water at the entry and exit from the meander becomes slower
  5. The meander becomes cut off from the river channel, forming an oxbow lake