Coasts

• What four parts is a system made up of?

  Inputs, outputs, stores or components and processes or transfers
• Inputs

  Energy and sediment brought into a coastal landscape
• Outputs

  The loss of energy/sediment from the coastal landscape
• Stores or components

  Where energy and/or sediment is stored in the landscape
• Processes or transfers

  Actions which link one part of the system to another
• Give examples of energy inputs in a coastal landscape

  . Wind

  . Waves

  . Tides

  . Ocean currents

  . Sun’s heat

  . Position of material on slope
• Give examples of sediment inputs in a coastal landscape

  . Offshore/marine

  . Fluvial deposits

  . Geology

  . Artificial stores
• Give stores that are erosional landforms

  . Headlands and bays

  . Cliffs

  . Wave cut platform

  . Cave, arch, stack, stump

  . Geos and blowholes
• Give stores that are depositional landforms

  . Beaches and spits

  . On shore bars

  . Tombolos

  . Salt marshes

  . Sand dunes

  . Estuaries
• Give examples of outputs in a coastal landscape

  . Sediment removed by marine and aeolian erosion

  . Evaporation
• What is longshore drift?

  Longshore drift is the name of the process where materials are moved along the coastline

  . Waves approach the coast at an angle

  . Swash carries sediment up the beach at an angle

  . Backwash carries sediment down the beach with gravity - at right angles to the beach

  . This creates a zig-zag movement of sediment along the beach
• What is a spit?

  An extended stretch of sand or shingle jutting out into the sea from the land. Spits occur when there is a change in the shape of the landscape or there is a river mouth
• How are spits formed?

  . Sediment is carried by longshoreman drift

  . When there is a change in the shape of the coastline, deposition occurs. A long, thin ridge of material is deposited (spit)

  . A hooked end can form is there is a change in wind direction

  . Waves cannot get past a spit, therefore the water behind the spit is very sheltered. Silts are deposited here to form salt marshes or tidal mudflats.
• What are sediment cells?

  A length of coastline within which the movement of sediment is largely self contained
• How many sediment cells are there in England and Wales?

  11
• What are the key features of sediment cells?

  .Closed systems

  .Inputs and outputs are mostly balanced

  .Well-defined boundaries (headlands, deep stretches of water)

  .Sources of sediment include rivers, cliff erosion, offshore sources

  .Sinks or stores of sediment e.g. beach ridges, spits, sand dunes, offshore banks
• What causes waves?

  Wind
• What is the distance over open water in which waves are formed called?

  Fetch
• What kind of energy are waves created from?

  Kinetic
• What kind of energy will waves possess as they break?

  Gravitational potential
• What type of waves occur in winter months and how do they influence the beach gradient?

  High energy waves often occur during winter months and tend to remove material from the top of a beach and transport it to the offshore zone, reducing beach gradient.
• What type of waves occur in summer months and how do they influence the beach gradient?

  Low-energy waves, typically of summer months, build up the beach face, steepening the gradient.
• What are the characteristics of constructive waves?

  .Gentle beach

  .Spilling waves

  .Deposition most common

  .Strong swash pushes sand up the beach

  .Weak backwash

  .Wave crests far apart

  . 6-8 waves per minute

  . Berms form on beach
• What are the characteristics of destructive waves?

  .Steep beach

  .Plunging waves

  .Erosion most common

  .Strong backwash pulls sand out to sea

  .Weak swash

  .Waves close together

  .13-15 waves per minute

  .Large ridge
• What is a tidal range?

  The difference in height between successive high and low tides
• What is the lithology of a rock?

  The characteristics of rocks especially their resistance to erosion and permeability
• What is the structure of a rock?

  Describes the joints, bedding planes and faults found within a rock
• what is strata?

  Layers of rock
• What are bedding planes?

  Horizontal cracks. These are natural breaks in the strata, caused by gaps in time during periods of rock formation
• What are joints?

  Vertical cracks. These are fractures, caused either by contraction as sediments dry out or by earth movements during uplift
• What is the dip of a rock?

  Refers to the arrangement of layers (strata) in the rock
• What are the characteristics of igneous and metamorphic rocks?

  They erode slowest because:

  . Have dense, interlocking crystals which are hard to break apart

  . Strong, resistance rocks which can form high vertical cliffs

  . Formed through millions of years of intense pressure (metamorphic)

  . Formed through cooled magma (igneous)
• What are the characteristics of sedimentary rocks (chalk/limestone)?

  Chalk is often described as a soft rocks but is fairly resistant to erosion so it can form high and steep cliffs especially if there are horizontal bedding plans and well compressed rock. Limestone has clear vertical and horizontal cracks in the rock and are weakened by weathering and erosion.
• What are the characteristics of clay, glacial deposits and mudstones?

  They erode quicker because:

  . Unconsolidated material, bonds between particles are weak and easily broken

  . Can’t form steep slopes so cliffs rend to be no more than 50m

  . Clay is formed through rocks interacting with water so will naturally be softer
• What are concordant coastlines?

  Has the same type of rock along its length