coasts

• what is the littoral zone


  an area of shoreline where land is subject to wave action. it's subdivided into offshore, nearshore, foreshore and backshore
• what is a coast

  land adjacent to the sea and often heavily populated and urbanised
• what is backshore


  above high tide level and only affected by waves during high tides and major storms
• what is foreshore


  where wave processes occur between the high and low tide mark
• what is nearshore


  shallow water areas close to land and used extensively for fishing, coastal trade and leisure
• offshore


  area of deeper water beyond the point at which waves begin to break i.e. open
• what is a rocky coastline

  has cliffs varying in height from a few metres to hundreds of metres, cliffs are formed from rock but the hardness of the rock varies
• what are coastal plains

  the land gradually slopes towards the sea across an area of deposited sediment, with sand dunes and mud flats being the most common example
• what is a concordant coast


  sometimes referred to as 'pacific coasts', these coastlines have alternating layers of hard and soft rock that run parallel to the coast, e.g. dalmatian coast
• what is a discordant coast


  sometimes referred to as 'atlantic coasts', these coasts have alternating layers of hard and soft rock that are perpendicular to the coast, e.g. west cork, ireland
• what are joints


  these divide rock strata up in blocks with a regular shape
• what are fissures


  smaller cracks in rocks. often they are only a few cm long
• what is a fault

  a major line of weakness within the rock. this causes large fractures
• factors that affect the size of waves

  • fetch is how far the wave has travelled
  • strength of the wind and depth of water
  • how long the wind has been blowing for
• what is a horizontal dip

  steep profiles of 70-80 degrees producing a very stable cliff with reduced rockfalls
• what is a seaward deep (high angle)


  vertical or near vertical profile with notches reflecting strata that are more easily eroded
• what is a seaward dip (low angle)


  sloping, low angle profile with a rock later facing the sea, vulnerable to rock slides down the slope
• what is a landward dip

  profile may exceed 90 degrees producing areas of overhanging rock, very vulnerable to rock falls
• what is a dip on cliff profiles

  dip is the angle of rock strata in relation to the horizontal. dip is a tectonic feature

  the angle of the cliff dip profile can cause erosion to occur at different rates along the coastline
• what is lithology


  the general physical characteristics of a rock or the rocks in a particular area
• what are synclines


  a downward, u-shaped fold in the layers of rock in the earth's surface
• what are anticlines


  an upward, curved fold in the layers of rock in the earth's surface
• how are anticlines and synclines formed

  tectonic forces (sometimes ancient) can deform rock layers through compressional (pushed together) and tensional (pulled apart) forces. under high pressure and heat, rocks may bend or break apart, e.g. dalmation coast, croatia
• how do waves form

  waves are created by wind blowing over the surface of the sea. as the wind blows over the sea, friction is created - producing a swell in the water
• why do waves break

  1. waves start out at sea
  2. as waves approach the shore, friction slows the base
  3. this causes the orbit to become more elliptical
  4. eventually the top of the wave breaks over
• what are constructive waves

  this wave as a swash that is stronger than the backwash. this therefore builds up the coast
• what are destructive waves

  this wave has a backwash that is stronger than the swash. this therefore erodes the coast
• what are tides and how are they caused

  tides are the periodic rise and fall of sea levels. they are caused by the gravitational pull of the sun and the moon. the moon pulls water towards it, creating high tides. on the other side of the earth, a compensatory bulge is created causing high tides there as well. the area between the two bulges are where the tides are at their lowest
• what are spring tides

  twice in a lunar month when the sun, moon and earth are all in a straight line, the tide force is at its strongest and highest
• what is a neap tide

  twice a month the sun and moon are positioned at 90 degrees to each other in relation to the earth
• what is erosion


  breaking down and removal of material by the movement of wind and water
• what is attrition


  rocks that bash together to become smooth/smaller
• what is solution


  a chemical reaction that dissolved rocks
• what is abrasion


  rocks hurled at the base of a cliff to break pieces apart
• what is hydraulic action

  water enters cracks in the cliff, air compresses, causing the crack to expand
• what is transportation


  a natural process by which eroded material is carried/transported
• what is solution


  minerals dissolved in water and are carried along
• what is suspension 


  sediment is carried along the flow of the water
• what is saltation


  pebbles that bounce along the seabed
• what is traction


  boulders that roll along a seabed by the force of the flowing water