coastal landscapes

• a concordant coastline have alternating bands of hard and soft rock parallel to the coast
• discordant coastlines have alternating bands of hard and soft rock at 90 degrees to the coast


  erosional landforms are more common on discordant coastlines
• in Dorset, the coastline consists of Portland limestone making headlands and bays
• rocks with joints and faults are more susceptible to the processes of erosion and weathering
• bedding planes that dip towards the sea create a gentler cliff profile than those that dip away from the sea
• bedding planes that dip towards land tend to create a steeper cliff profile


  these cliffs are more vulnerable to erosional processes
• the angle that the rock layer forms with the horizontal bedding plane is referred to as the dip
• igneous rocks, such as granite, form from the crystallisation of magma


  they are more resistant to erosion and weathering
• sedimentary rocks, such as limestone, forms from the build up of sediments compacting together


  more susceptible to weathering
• metamorphic rocks such as marble are formed from the change in the structure of sedimentary rocks and igneous rocks, caused by heat and pressure


  resistant to erosion
• the existence of sedimentary, igneous and metamorphic rocks affects the rate of recession along a coastline
• vegetation is important in supporting the development of sandy coastlines
• sand dunes need a continuous supply of sand, wind and obstacles to trap sand, like plants
• a typical sand dune transect goes from the mobile dune, nearest the sea (embryo, fore and yellow) to the fixed dunes nearest the back ( grey dunes and dune slack)
• xerophytes can withstand periods of dry weather
• halophytes can withstand high concentrations of salt water
• yellow dunes tend to be colonised my marram grass


  they have deep roots and are salt tolerant
• how do igneous rocks form?

  from the crystallisation of magma