4 mark questions

Question 1

Explain the formation of barrier beaches

Answer 1

• extension of a spit
• longshore drift moves sediment across coastline until change in direction
• deposition occurs, a spit develops and eventually it reaches across the whole bay
• colonisation by vegetation can stabilise the barrier beach, trapping further sediment

Question 2

Outline the process of sub-aerial weathering in the development of coastal landscapes

Answer 2

• Chemical weathering occurs when weak carbonic acid in rainwater attacks limestone cliffs
• Mechanical weathering occurs when repeated freezing and thawing of water absorbed in pervious rock leads to the breakdown of rocks
• Biological weathering refers to the burrowing of plants and animals into the rock at the coast
• Sub-aerial weathering involves the action of rainwater and insolation upon landforms in the coastal landscape

Question 3

Outline the process of coastal hydraulic action

Answer 3

• process of marine erosion
• via the sheer force of water alone without any debris
• With high energy waves this can exert enormous pressure on the rock surface, weakening or breaking off rock particles

Question 4

Explain the development of saltmarsh environments

Answer 4

• develop in sheltered estuaries behind spits
• the area behind it becomes sheltered
• Silt is deposited by the river which gradually builds up to form mudflats
• stabilised/colonised by halophytic vegetation

Question 5

Explain the difference between eustatic, isostatic and tectonic sea level change

Answer 5

• Eustatic change is a global, whereas isostatic is a more localised
• isostatic is regional changes in land relative to the sea, eustatic is global changes in sea level relative to the land
• glaciation/ice can cause isostatic, when it melts- rebound
• Tectonic change is brought about by tectonic activity usually at plate boundaries. This can cause dramatic and immediate changes to the land relative to the sea
• eustatic fjords, isostatic raised beaches

Question 6

Explain the concept of the sediment cell

Answer 6

• A sediment cell is a closed system usually bounded by headlands or a change in longshore drift
• there is erosion, transport and deposition of sediment
• inputs into the sediment come from erosion from the sea bed or land
• little or no movement of sediment between cells

Question 7

Outline characteristics of high energy coasts

Answer 7

• exposure to strong and steady prevailing winds
• create high energy waves
• rates of erosion greater than deposition
• erosional landforms including headlands, cliffs and wave-cut platforms

Question 8

Outline characteristics of constructive waves

Answer 8

• Constructive waves have a long wave length
• low amplitude
• longer period
• stronger swash than backwash

Question 9

Outline how the coast is described as a natural system

Answer 9

• described as an open system
• Inputs originate from outside the system
• example energy from waves, wind, sediment from rivers
• Outputs move to the outside
• linked to other natural systems

Question 10

Outline the role of wind in affecting coastal energy

Answer 10

• generation of waves as friction occurs at the surface of the water
• stronger winds = higher energy/destructive waves
• Wind also affects currents
• potential for longshore drift

Question 11

Why are waves important in transport?

Answer 11

• Longshore drift is the gradual movement of sediments along a
  coastline
• waves strike the coast at an angle, sediments are moved up the beach at that same angle with the swash
• backwash returns sea water and sediments perpendicular to the
  coastline
• Repeated wave action in this way moves sediments along parallel to the coastline