Geography 2

• Littoral zone


  The breakwater area where waves come onshore, nearest to the coastline where high and low tides happen
• Sections of the littoral zone

  • Offshore
  • Nearshore
  • Foreshore
  • Backshore
• Offshore


  • Farthest section out to sea, deepest area where waves start to break
• Nearshore


  • Closer to coast, area of shallow water beyond low tide mark, more friction between seabed and waves distorts the waves
• Foreshore


  • Area between high and low tides, covered in water during high tide and exposed during low tide
• Backshore


  • Area above high tide mark, affected by wave action only during storm events
• Types of coastlines


  • Rocky/cliff
  • Sandy
  • Estuarine
• Rocky/cliff coastline


  • High relief, resistant rock, high energy environment, erosion greater than deposition, destructive waves
• Sandy coastline


  • Low relief, soft rock, deposition greater than erosion, constructive waves with strong swash and weak backwash
• Estuarine coastline


  • Low relief, salt marshes, river mouth, deposition greater than erosion, low energy environment
• Dynamic equilibrium


  Balance between inputs of sediment, outputs, and flows of sediment due to energy at the coastline
• Short-term coastal classifications


  • Tides
  • Currents and river flows
  • Precipitation
  • Gravity and tectonics
  • Sediment inputs and deposition/erosion rates
  • Advancing/retreating coastlines
  • Emergent/submergent coastlines
• Long-term coastal classifications


  • Geology/lithology
  • Concordant/discordant coastlines
  • Sea level changes
  • Tectonic plate movements
  • Climate change
• Rocky coastline in UK

  • Around 1000km, mainly in north and west, resistant geology, high energy erosion but slow erosion rates, little deposition
• Sandy plain coastline in UK

  • Flat or gently sloping, wetlands and salt marshes, low energy environment, high deposition rates, can be sand, shingle or cobbles, mainly in south and east
• Concordant coastline


  Rock runs parallel to the sea in one consistent band
• Discordant coastline


  Differing bands of hard and soft rock perpendicular to the sea
• Concordant coastline examples


  • Georgia, South West UK
• Discordant coastline examples


  • East coast UK, Holderness
• Other coastline types


  • Dalmatian coastline (Croatia)
  • Half-coast lines (e.g. Curonian Spit)
• Coastal dip


  Angle of rock from horizontal, produces different cliff profiles
• High angle seaward dip


  • Slow, low-sloping angled profile, vulnerable to subaerial processes and weathering
• Low angle seaward dip


  • Steeper profile, can exceed 90 degrees, leads to major cliff collapse from undercutting
• Faults


  Major fractures in rock created by tectonic plates, increase rate of erosion
• Joints


  Fractures in rock that can also increase erosion rates
• Degrees which produces a slow low sloping angled profile

  • Run lock fade one lock facing the sea
  • Vulnerable coastlines
  • Vulnerable to be attacked by subaerial processes and weathering
• Low angle of sea wood dip

  • Produces a steeper profile of the rock which may even exceed 90 degrees
  • Produces major cliff collapse
• Marine erosion


  1. Creates an overhang

  2. Leads to cliff constantly collapsing and collecting into the sea
• Faults


  • Major fractures created by tectonic plates
  • Increase the rate of erosion
  • Lead to rocks being easily eroded over time
• Joints


  • Fractures without the rock being moved
  • Caused by weathering and compression
• Fissures


  • More open than fractures and joints
  • Deep open ravines in rock
• Folding


  • Bends that occur in rock
  • Produce a layering effect
  • Main types are anticlines and synclines
• Rock type in bedrock at the sea

  • Influences the rate of coastal recession or retreat
  • Influenced by how reactive the rock is to chemicals
  • Influenced by whether the rock is less resistant or more resistant
• Igneous rocks


  • Erode very slowly
  • Weather very slowly
  • Crystals are interlocking
  • Form x-like shapes and bands
  • Contain very few joints and weaknesses
  • One of the hardest and most resistant types of rocks
• Metamorphic rocks


  • Recrystallized or reformed through heat and pressure
  • Have a crystalline structure made up of crystals
  • More resistant than sedimentary rocks but less resistant than igneous rocks
• Sedimentary rocks


  • Formed by compression and compaction over millions of years
  • Least resistant type of rock
  • Heavily jointed and cracked
  • Have weak structures
  • Moderate erosion rates, erode faster than igneous and metamorphic rocks
• Unconsolidated sedimentary material


  • Alluvium - not yet cemented or compacted sand and other types of rocks
  • Very easily eroded at around 2-10 meters per year
• Less resistant layers or bands of rock or strata

  • Erode quickly and weather quickly
  • Produce wave cut notches
• Resistant rocks


  • Erode slowly and weather slowly
  • Form a bench at the cliff base
  • Lead to an overhang of the cliff above
• Permeable rocks


  • Allow water to travel through them due to pores and joints
  • Tend to be less resistant as weathering can take place more easily