coasts

• arch’s to stacks

  • Erosion of cracks and faults in a headland can, in time, lead to the formation of a cave.
  • Continued erosion along lines of weakness, can break through to the other side of the headland, forming an arch.
  • Weathering of the roof of the arch could lead to a rockfall event and its collapse leaving behind a stack of rock.
• LSD is the zig zag movement of swash and backwash along a beach.
• fetch

  the distance of open water over which the wind can blow, the longer the fetch the more powerful wave
• swash is the forward movement of a wave up a beach
• backwash is the backward movement of a wave down a beach once the wave has broken
• spits are long narrow sandy deposits that form when there is a change in direction of the prevailing winds or currents
• concordant coastline is a coastline where the rock type and structure runs parallel to the coast.
• Concordant coastlines are formed when the rock layers that underlie the coast are parallel to the shore. This means that the rock type and structure do not vary significantly along the length of the coast. 
• discordant coastline is a coastline where the rock type and structure runs perpendicular to the coast. This results in a coastline that has many bays, headlands
• Discordant coastlines are formed when the rock layers that underlie the coast are perpendicular or at an angle to the shore.
• • for a cove to form, hard and soft rock must alternate
  • the hard rock may suddenly crack due to erosion weakening the cliff face
  • over time the hard rock erodes to expose the less resistant soft rock behind
  • the soft rock is less resistant so erodes quicker than the hard rock, so the cove widens in the soft rock more
  • erosion continues to widen but cannot break through the tough hard rock
• Wind, that produces waves, influences how quickly sediment is moved along a beach by the swash and backwash of longshore drift.
• • Storms generate destructive waves where the backwash has more energy than the swash, removing sediment from a beach and making it smaller.
• In summer there are more constructive waves, where the swash has more energy than the backwash, meaning that beaches are built up and made bigger by them.
• Discordant coastlines –

  90° to the sea,

  leading to alternating bands of hard and soft rocks

  creating a coastline formed of bays and headlands,

  e.g. Pembrokeshire coast.
• The building of groynes can stop longshore drift,

  resulting in the deposition and build-up of sediment which increases the size of the beach.

  This reduces the erosion rate of cliffs as wave energy is reduced by the deposition.