Pa rtic dia les m go ov na ed lly
8 Coastal environments
Particles roll back to new position
Beach
Wave fronts meeting beach at an angle
Wind direction Groyne
Beach
Beach material piled against groyne
Now test yourself
Direction of longshore drift
Source: Advanced Geography: Concepts & Cases by P. Guinness & G. Nagle (Hodder Education, 1999), p.295
5 Explain what is meant by the term ‘littoral cell’ (sediment cell). 6 Distinguish between bedload and suspended load.
Answers on p.218
Figure 8.6 Longshore drift
Tested
8.2 Coastal landforms of cliffed and constructive coasts Cliffs and erosion
Revised
Cliff profiles are very variable and depend on a number of controlling factors. One major factor is the influence of bedding and jointing. The dip of the bedding alone will create varying cliff profiles. For example, if the beds dip vertically, then a sheer cliff face will be found. By contrast, if the beds dip steeply seaward, then steep, shelving cliffs with landslips will be found. To some extent each cliff profile is unique, but a model of cliff evolution or modification has been produced to take into account not only wave activity, but also sub-aerial weathering processes (Figure 8.7).
Sea level
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A cliff is a rock-face along the coast, where coastal erosion, weathering and mass movements are active and the slope rises steeply (over 45°) and for some distance.
Cliff
Wave-cut platform Source: Goudie, A, The Nature of the Environment, Blackwell, 1993
Figure 8.7 Evolution of wave-cut platforms
120
Cambridge International AS and A Level Geography Revision Guide
