Beach Profiles

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Beach Profiles

  1. 1. Beach Profiles<br />AS Geography<br />
  2. 2. Learning Objectives<br />Understand that beaches contain different landforms created by deposition<br />Look at the associated features of beaches<br />Understand the key terms and factors that dictate how each feature is formed<br />
  3. 3. What is a beach Profile?<br />What can you tell me about beaches?<br />The are full of sediment<br />They constantly change<br />They are a store of inputs<br />They are the source of outputs<br />They are buffer between the land and the sea<br />
  4. 4. Most Beaches have 3 main components<br />Nearshore<br />Foreshore<br />Backshore<br />
  5. 5. Nearshore<br />What factors affect the nearshore<br />
  6. 6. Nearshore<br />Zone extending seaward of the shoreline well beyond the breaker zone. Zone in which nearshore currents occur.<br />The gentle gradient results from the smoothing out of sediment associated with the back and forth movement of the waves<br />Due to the loss of energy, some sediment can be deposited in sand bars<br />
  7. 7. Foreshore<br />What factors affect the foreshore?<br />
  8. 8. Foreshore<br />Once a wave breaks, its water moves as a sheet upslope as swash, and falls back toward the sea as backwash. The narrow area in which this occurs is called the swash zone.<br />The location of swash zone shifts due to the rising and falling of the water level, associated with tides.<br />The area affected by the swash zone on a daily basis is called the foreshore (between low and high tide marks)<br />
  9. 9. As the flow of swashslows (and eventually stops) in its upper reaches, some of the sediment carried by the water can be deposited. <br />But much of the sediment is returned back down to the upper shoreface due to backwash.<br />
  10. 10. Describe the changing characteristics of the storm beach from SW to NE. (7 marks)<br />
  11. 11. Backshore<br />What effects the backshore?<br />
  12. 12. Backshore Zone<br />Beyond the Foreshore is a backshore zone, characterized by dunes. <br />Sediment can also be transported to the backshore area during storms, when big waves can reach far inland.<br />
  13. 13.
  14. 14. The features<br />Berms <br />A nearly horizontal or landward-sloping portion of a beach, formed by the deposition of sediment by storm waves<br />
  15. 15. Ridges and Runnels<br />Ridgesare areas of the foreshore that are raised above the adjacent shore which dips into a Runnel. The cross-section is similar to that of hills and valleys.<br />Ridge and Runnel Systems are formed due to the interaction of tides, currents, sediments and the beach topography. They will only form on shallow gradient beaches<br />
  16. 16. Cusps<br />Beach cusps are rhythmic shoreline features formed by swash action<br />They develop in a variety of environments but commonly on coarse-grained beaches with low wave energy<br />
  17. 17. Spits<br />long narrow ridges of sand and shingle which project from the coastline into the sea.<br />They begins due to a change in the direction of a coastline - the main source of material is from longshore drift<br />Where there is a break in the coastline and a slight drop in energy, longshore drift will deposit material at a faster rate than it can be removed and gradually a ridge is built up, projecting outwards into the sea <br />
  18. 18. Bars<br />A bar may form where there a changes in coastal direction and drop in tidal energy creating sedimentation<br />
  19. 19. Using pages 93 to 96 answer these questions:<br />Distinguish between a spit, bar and tombolo<br />Outline three pieces of evidence that indicate the direction of longshore drift along a coastline.<br />Using an example(s), describe the main features of a spit. (Draw annoted sketch)<br />Choose either a beach or a spit. Describe the chosen landform and explain the role played by longshore drift in its formation<br />

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