low energy coast - North Norfolk coast

• spec:

  • physical factors influence the formation of landforms
  • inter-relationship of landforms
  • how and why landforms change over time
• outline the coastal currents - physical factors

  • the coast is the meeting point between Scottish coastal waters and English Channel waters
  • there are currents from the North Atlantic drift
• outline the tides - physical factors

  • avg tidal range is 4 - 6 metres
  • spring tide is 5 - 6 metres
  • during neap tides, Blakeney is at 2 metres but Sheringham is at 3 metres
  • tidal marks are visible on all landforms and some are intertidal
• outline the geology - physical factors

  • almost entirely sedimentary
  • the eastern extent is newer sandstone and other mineral from the quaternary period
  • the centre is made of cretaceous limestone
  • during the last glacial maximum (22000 years ago) the coast was covered in ice sheets and when they melted , material from the ice was deposited which resulted in glacial till
  • glacial till = an impermeable layer of boulders and clay
• outline the winds - physical factors

  • in the spring and summer , winds come from the south which are calmer and creates milder conditions resulting in more spilling waves
  • in the autumn and winter , winds come from the north which are stronger and colder resulting in rough seas and more frequent storms which results in more coastal erosion from plunging waves
  • there have been many storm surges that have affected the north Norfolk coast. for example Storm Ciara in February 2020
• landforms in order:

  1. sheringham cliffs
  2. salthouse and cley beaches
  3. blakeney point spit
  4. blakeney point salt marshes
• outline the sheringham cliffs - landforms

  • the cliffs are composed of glacial till , sand and gravel making them more vulnerable to erosion
  • the cliffs have a height of 10 - 40 metres
  • lower layers of geology are made of clay and older glacial deposits making it more resistant to erosion
  • upper layers are made of sand and gravel which is vulnerable to erosion
  • slumping is common and the base is eroded by the sea
• outline the salthouse and cley beaches - landforms

  • the beach is composed of shingle which is usually flint released from the eroded glacial till cliffs of sheringham
  • the shingle is transported east from sheringham cliffs by long shore drift and deposited along the coastline
  • some shingle is also from offshore marine deposits
  • the beach has a steep profile but changes seasonally and during storms
  • if storm water breaches the ridge = flooding of the salt marshes
• outline the blakeney point spit - landforms

  • formation began 4000 - 6000 years ago when post-glacial sea level rise allowed enough deposition
  • begins at cley-next-the-sea on the mouth of the River Glaven where the coastline changes direction towards blakeney
  • approx. 6.4 km in length
  • already well established by the 18th century
• outline the blakeney point salt marshes - landforms

  • formed due to deposition of fine sediment behind the spit
  • composed of silt , clay , organic material
  • has channels were tidal seawater can enter and drain. the channels also interact with the Glaven estuary
  • the lower marsh contains pioneer species and experiences frequent flooding
  • the upper marsh contains more biodiversity and experiences less flooding