Geog

• What accounts for the majority of sediment in the coastal zone?

  Rivers
• Why are estuaries important wildlife habitats?


  They are brackish and provide a unique environment for various species.
• When does most erosion occur along coastlines?

  During the winter months due to frequent storms.
• What is a coastal energy source that can cause sand to be blown along a beach?


  Wind
• Where does sediment transport by winds typically occur?

  In sand dunes, glacial, and desert environments.
• How do glaciers contribute to sediment deposition?


  They deposit sediment stored in the ice when they calve into the ocean.
• How is sediment transferred to the coastal zone?


  Through waves, tides, and currents eroding offshore sediment sinks.
• What is longshore drift?


  It is the movement of sediment along the beach due to prevailing winds altering wave direction.
• What are the main sources of energy at the coast?


  • The sun is the primary energy source for natural systems.
  • High winds form offshore waves.
• How do waves form?


  Waves form when wind moves across the surface of the water.
• What happens to wave height as they approach the coastline?


  The wave height increases as they approach the coastline.
• What is the wavelength?


  The distance between two wave crests.
• What occurs when waves enter shallower water?


  The wavelength reduces, causing waves to break and surge up the beach.
• What factors affect wave energy?

  Strength of the wind, duration of the wind, and size of the fetch.
• What type of waves build up and create a beach?


  Constructive waves
• What are the characteristics of constructive and destructive waves?

  **Constructive Waves:**

  • Formed by smaller systems in the ocean
  • Long wavelength
  • 6-8 waves per minute
  • Low waves that build up the beach
  • Occur on gently sloped beaches

  
  

  **Destructive Waves:**

  • Formed by larger storms with strong winds
  • Short wavelength
  • 11-16 waves per minute
  • High waves that plunge onto the beach
  • Occur on steeply sloped beaches
• When do destructive waves dominate?


  In winter months.
• What effect do constructive waves have on beaches?


  They increase the width of beaches.
• What happens to beaches during storms with destructive waves?


  Destructive waves may erode beaches rapidly.
• How does coastal management affect wave types?


  It may affect the type of waves that occur.
• What is the negative feedback process between beaches and waves?


  • Destructive waves cause deposition at cliff bases.
  • Material is removed from the upper beach profile.
  • Destructive waves become less powerful as they approach the beach.
  • This leads to the creation of constructive waves.
  • Beach profile becomes gentler in summer with fewer storms.
• What is the difference in height between high tide and low tide called?

  Tidal range
• When do spring tides occur?


  When the sun and moon are in alignment.
• What is a neap tide?


  It occurs when the sun and moon are perpendicular, creating the smallest tidal range.
• What are rip currents?


  Powerful underwater currents occurring close to the shoreline.
• What are the characteristics of high-energy and low-energy coastlines?

  **High-Energy Coastlines:**

  • Powerful waves
  • Exposed to large fetch
  • High headlands and sea cliffs
  • Frequent destructive waves
  • Erosion exceeds deposition

  
  

  **Low-Energy Coastlines:**

  • Less powerful waves
  • Occur in sheltered areas
  • Constructive waves prevail
  • Sandy areas with deposition exceeding erosion
• What is wave refraction?


  It is the process by which waves turn and lose energy around a headland.
• What is the negative feedback process related to headlands and bays?


  • Erosion forms headlands from resistant rocks.
  • Bays form where less resistant rocks are found.
  • Wave processes reduce the coastline in bays.
  • Headlands are worn away, shortening erosion in bays.
• What are the main processes of marine erosion?


  • **Corrosion:** Sand and pebbles hurled against cliffs.
  • **Abrasion:** Sediment wears down the shore.
  • **Hydraulic Action:** Air compresses in cracks, causing rock breakage.
  • **Implosion:** High-pressure waves create jets of water that erode.
  • Corrosion (solution): Mildly acidic seawater erodes alkaline rocks.
  • **Wave Quarrying:** Breaking waves pull away rocks from cliffs.
• What factors affect coastal erosion?


  Waves, beach slope and profile, activity of geomorphic processes, rock faults, and rock lithology.
• What are the processes of transportation in coastal environments?

  • **Traction:** Large, heavy sediment is moved.
  • **Suspension:** Fine sediment is carried within water currents.
  • **Saltation:** Smaller sediment bounces along the sea bed.
  • **Solution:** Dissolved material is carried within the water.
• How does longshore drift occur?


  Waves hit the beach at an angle determined by the prevailing wind.
• What causes deposition to occur?


  When sediment becomes too heavy for the water to carry or if wave energy changes.
• What happens in high-energy environments regarding sediment?


  Smaller sediment continues to be transported, while larger rocks are deposited.
• What is weathering?


  The breakdown of rocks over time, leading to material transfer into sediment cells.
• What is the positive feedback process related to weathering?


  • Higher removal rate of weathered rock promotes further weathering.
  • Increases exposed rock area.
  • Increases erosion and supply of rocks for erosion processes.
• What is the negative feedback process related to weathering?


  • Slower removal of weathered rock leads to debris buildup.
  • Reduces exposed cliff area.
  • Decreases weathering and erosion rates.
• What are the types of mechanical/physical weathering?

  • **Freeze-Thaw (Frost Shattering):** Water freezes in cracks, expanding and causing cracks to widen.
  • **Salt Crystallisation:** Saltwater evaporates, leaving salt crystals that widen cracks.
  • **Wetting and Drying:** Rocks expand when wet and contract when dry, leading to cracking.
• What is the process of freeze-thaw weathering?


  Water enters cracks in rocks, freezes, and expands, causing cracks to widen.
• How does salt crystallisation contribute to weathering?


  Salt crystals grow in cracks, forcing them to widen over time.