3.a. Emergent coastal landscapes form as sea level falls

Question 1

What is eustatic sea level change

Answer 1

• this is a global change in the volume of sea water, resulting from a rise or fall in the level of the sea itself e.g. caused by the retreat of ice following a glacial period
• eustatic changes are influenced by variations in mean global temperature

Question 2

What is isostatic sea level change

Answer 2

• this is a local change in sea level resulting from the land rising or falling relative to the sea e.g. tectonic movements
• isostatic related to vertical movements

Question 3

What are emergent landforms

Answer 3

• these are landforms that form as sea level falls
• they may be found inland, some distance from the coastline
• examples are raised beaches, marine terraces and abandoned cliffs

Question 4

What physical factors affect changed in global temperature and the volume of water in the oceans

Answer 4

• variations in the earths orbit
• variations in solar output
• major volcanic eruptions
• variations in the tilt of the earth’s axis

Question 5

How does climate change lead to sea level fall

Answer 5

fall in global temperature, more precipitation in the form of snow, snow turns to ice, more water stored on the land as solid ice raher than liquid water which is returned to the oceans

Question 6

Describe how climate changes occurred during a previous time period and the resultant sea level fall

Answer 6

• over the past 400,000 years, the temperature change increases every 100,000 years and it fluctuates. Great fluctuations in temperature change are much closer together in inter-glacial periods
• over the past 400,00 years, sea level has declined massively from the 1st inter glacial period

Question 7

Würm glacial period (25,000 years ago)

Answer 7

-temperatures were 9 degrees lower and sea level was 90m lower than present

Question 8

Riss glacial period (108,000 years ago)

Answer 8

-tempertaures 7 degrees lower and sea level was 83m lower than present

Question 9

How does sea level fall influence geomorphic processes and landforms

Answer 9

• landforms shaped by wave processes when the se level was higher are exposed when sea level falls
• they may be found inland from present coastlines
• these landforms includes raised beaches and abandoned cliffs

Question 10

What landforms are formed as sea level fallls

Answer 10

• raised beaches are areas of former shore platforms that are left at higher level than the present sea level
• they are found a distance inland from tthe present coastline
• behind the beach along the emergent coastline, abandoned cliffs can be found
• marine terraces are at a much larger scale and are formed during a previous period of higher sea level
• on the southern tip of the Isle of Portland, there is a raised beach which has a height of 15m above sea level-formed 125,000 years ago

Question 11

How are these landforms modified by present and future climate and sea level change

Answer 11

• geomorphic processes-landform affected by weathering and mass movement
• in post glacial periods when the climate is wetter and warmer, vegetation develops
• warming is predcited in the future, and this could lead to chemical and biological weathering becoming more influential
• if the rise in temperature is enough for sea level to rise, these emergent features may then becomecloser to the coastline and wave processes will be an influential factor

Question 12

What is Flandrian Transgression

Answer 12

This is the significant rise in sea levels