coastlines

• sandbars form when a sandpit stretches all the way across a bay to reach land on the other side. if a river flowing into the bay a fresh water lagoon may form.
• a tombolo forms when a sandspit stretches and connects to an island.
• sand spits grow outwards into the sea or a river from the far end of a lacteral beach.
• sand spits form as a result of long shore drift. the swash laps onto the shore at an angle, pushing material up the beach in the same direction. the backwash returns to the sea at a perpendicular angle as it is driven by gravity on the slope of the beach.
• when the coastline changes direction, the process of LD contest in the same direction as before.
• Crack

  Vertical joint or crack in sedimentary rock (e.g. chalk)
• Sedimentary rock


  • Chalk
• Erosion of joint by sea

  Erodes joint into a cave on either side of the headlands
• Cave

  • Forms when 2 caves form back to back and eventually connect to form an arch
• Arch

  • Forms when 2 caves connect back to back
• Stack


  • Formed by continued erosion of an arch until the roof is no longer supported and collapses due to the force of gravity
• Stump

  • Remaining part of a stack after further erosion
• cliff form easily when the rock type is sedimentary. this because sedimentary rocks contain bedding planes (horizontal layers) and joints (vertical cracks)
• when the tide is in, the sea attacks weakness at the base of the slope to create a wave-cut notch. the notch forms as a result of erosion.
• once the wave-cut notch is large enough the cliff face will collapse. this is made easier due to the vertical joints in the rock. a steep cliff face starts to appear. this process will continue until the cliff is fully formed. at the base of the cliff a wave-cut platform is revealed at low tide.