Coasts - landscape development

Question 1

How are headland and bays formed?

Answer 1

Areas with alternating hard and soft rocks, the soft rocks erode quicker forming bays, and the harder rocks erode slower forming headlands – headlands receive highest energy waves and bays get lower energy waves allowing more deposition forming beaches.

Question 2

How are wave cut platforms formed?

Answer 2

Wave Cut platforms form when a=waves penetrate base of cliff creating wave cut notch, as the cliff retreats over time it creates a wave cut platform.

Question 3

How are the features on a headland formed?

Answer 3

cracks, caves, arches, stacks, stumps

Question 4

How are depositional landforms formed?

Answer 4

• Prevailing winds push waves along a beach, longshore drift collects and deposits sediment along the mouth of an estuary forming a spit over time. (then a mudflat and salt marsh form on the inside of the spit).
• Same thing occurs across a bay to form a bar and lagoon.
• Tombolo = same thing occurs across to an island along off a beach.

Question 5

How are sand dunes formed?

Answer 5

• Sand is trapped at the back of a beach at high tide
• An embryo dune accumulates from windblown sand stabilising the surface
• These grow over time and build up of more sand called fore dunes and vegetation begins to grow
• Fixed dunes gradually form.

Question 6

How are mudflats formed?

Answer 6

• Sheltered shorelines that are not exposed to powerful waves, they are often submerged at high tide and are made from slit and clay
• Where a river (fresh water) and sea (saltwater meet) sediment and fine materials are deposited
• These particles form together due to flocculation and the larger particles deposit on the seabed with little currents. Over time this process forms mudflats.

Question 7

How do salt marshes form?

Answer 7

These form a similar process to the sand dunes with sediment building up in land from the mudflat above the high tide mark allowing pioneer plants to grow, as these grow more plants are colonised the land rises.

Question 8

Explain eustatic and isostatic change?

Answer 8

• Eustatic change = sea level change
• Isostatic change = land changes
  These changes occur over thousands of years.

Sequence of sea level rise:
- Pillow analogy:
During a glacial period when there were glaciers on the Scottish Highlands the land underneath was heavier – this means the land in the southeast of England is higher from sea level as there is less water entering the ocean causing eustatic fall. Over thousands of years the ice from glaciers melts causing the land in Scotland to rebound and rise as there is less weight, this intern causes the land in the southeast to fall like a pillow when you take your hand off it.

Question 9

Name 2 submergent features and how they are formed?

Answer 9

Submergent features form when eustatic change occurs – a fjord forms when a U-Shaped valley is flooded, and a Ria is formed when a V-shaped valley floods.
Dalmatian coast also a submergent landform but it runs parallel to the coast not at a right angle inland like a ria or fjord.

Question 10

Name an emergent feature and how it’s formed?

Answer 10

Emergent features like a raised beach form when land previously lower due to weight from ice melts and isostatic rebound occurs. E.g. North Scotland