3.b. Submergent coastal landscapes form as sea level rises

Question 1

What are submergent coastal landforms

Answer 1

-landfroms that form as sea level rises

Question 2

How does climate change lead to sea level rise

Answer 2

rise in global temperature, melting of ice stores on the land, increase in the volume of water in the oceans, sea level rise. A 1degrees rise in global temperature could lead to a rise of 2m at sea level

Question 3

How does sea level rise influence geomorphic processes and landforms

Answer 3

• the main influence of a rise of sea level is the submergence of river valleys, forming rias, and glacial valleys forming fjords
• shingle beaches appear when former coastal sediment is pushed onshore by wave action

Question 4

Description of rias

Answer 4

• submerged river valleys, formed as sea levels rise
• the lowest part of a rivers course and the floodplains are submerged
• the higher valley sides, middle and upper course remain exposed
• the centre is deeper and the exposed valley sides slope

Question 5

Example of rias

Answer 5

• examples found in Devon and cornwall
• names include Fowey and Kingsbridge
• alluvial deposits were laid down during glacial periods
• thresholds can form at the mouth of each river

Question 6

Modification of rias and fjords

Answer 6

• modified by the wave processes acting on their sides at the present day sea level
• the valley sides may be affected by the operation of sub-aerial processes-lead to a reduction in the steepness of the valley sides of fjords
• sea levels predicted to rise by 0.6m in the next 100 years
• marine erosion will increase

Question 7

Description of fjords

Answer 7

• submerged glacial valleys
• steep, cliff like valley sides
• u shaped cross section
• the threshold at the end is shallower due to limited erosion
• further deepened during the Flandrain Transgression

Question 8

Example of fjords

Answer 8

• can be found in Scotland, Norway and Nea Zealand

- scottish fjords less well developed as ice was never thick

Question 9

Description of shingle beaches

Answer 9

• when sea level falls and the land based ice increases, large areas of ‘new’ land emerge
• rivers, meltwater and constructive waves accumulate sediment on the surfaces
• as eustatic level rise occurs, wave processes puch sediments onshore
• contribute to the formation of tombolos and bars

Question 10

Example of shingle beaches

Answer 10

• Chesil beach is a tombolo formed during Flandrian transgression
• sediment was carried into the English Channel by meltwater during Würm glacial period
• as sea levels rose, sediment was carried north east due to a south westerly wind

Question 11

Modification of shingle beaches

Answer 11

• the tombolo at Chesil beach has been affected by longshore drift
• shingle may move northest and a beach will cause storms