Coastal Landscapes - 2B.2-2B.3

Question 1

What are the four erosion processes

Answer 1

Hydraulic Action: air becomes trapped in joints and cracks - air is compressed when waves breaks which weakens cliff
Abrasion: bits of rock and sand in waves grind down cliffs
Attrition: waves smash rocks and pebbles into each other making them smoother
Solution: acids in sea water dissolve some types of rock

Question 2

What are features of a high energy coastline

Answer 2

Destructive waves, stormy conditions, long fetches, atlantic coasts, rocky landscape, wave-cut platform, cliffs

Question 3

what are features of a low energy coastline

Answer 3

constructive waves, deposition and transport, short fetches, beaches, spits, lowland coasts

Question 4

Marine erosion
- cliff profiles
- processes

Answer 4

• cliff steep and unvegetated
• little rock debris at base as its transported by waves
• undercutting

Question 5

Subaerial erosion
- cliff profile
- processes

Answer 5

• cliff not actively eroded at their base by waves
• shallower and curved profiles with lower reliefs
• surface runoff and mass movement move rock down downslope
• limited marine erosion means its not transported

Question 6

What is a fault and a joint

Answer 6

Fault: fracture surface in earth’s crust
Joint: crack in a rock without any clear signs of movement

Question 7

How do discordant coastlines change

Answer 7

• headland will be eroded more overtime which reduces the difference between them smoothing the coast line

Question 8

Describe the process of wave refraction

Answer 8

-as waves approach shallow water offshore headlands they slow down and wave height increases
-in bays wave crests curve to fill the bay decreasing wave height
-straight waves crests refract spreading out in bays and concentrating on headlands

Question 9

What is a fissure and fault

Answer 9

Fissure: smaller cracks in rock (than joints) that represent weaknesses erosion can exploit
Faults: major weaknesses in rock layers either side of a fault line (often fractured or broken)

Question 10

What are the rates of erosion and locations of 4 types of rock

Answer 10

Igneous (granite) - very slow - cornwall 1 mm/yr
Metamorphic (marble) - slow - North Wales 1mm-1cm/yr
Sedimentary (limestone) - moderate - joints make them permeable - deveon 1 cm-1 m/yr
Unconsolidated (boulder clay) - fast - not cemented - Holderness 1 m-10 m/yr

Question 11

How are sand dunes formed

Answer 11

• form from wind blown sand that is initially deposited against an obstruction (rock)
• as more sand particles are deposited the dune grows in size, forming rows at right angles to the prevailing wind direction
• if vegetation, such as marram grass and lyme, begins to grow on the dune its roots will help to bind the sand together, stabilising the dune

Question 12

What are Halophytes and Xerophytes

Answer 12

Halophytes - plants that can tolerate salt water
Xerophytes - plants that can tolerate very dry conditions

Question 13

How does vegetation help to stabilise dunes

Answer 13

• Pioneer species (marram grass) which are halophytic trap sand which lead to formation of embryo dunes
• In yellow (main) dunes marram grass can grow long roots to bind the sand together
• Further inland climax vegetation is found (trees) as soil is more nutrient and moist as water table is close to surface

Question 14

What is the involvment of vegetation is salt marshes

Answer 14

• green algae (first plants to colonise inter-tidal mudflats) can tolerate being submerged for up to 12 hours
  –> trap mud causing it to accumulate
• Spartina (pioneer stage) has long roots to stabilised mud and enables it to trap more - halophytes
• Lavender (stabilisation stage) - form a thick mat increasing salt marsh height (tolerate 4 hours of submergence )
• Climax vegetation further inland can grow as soil profile has developed - only submerged by high spring tides