KQ3-Emergent Landforms

Question 1

What is eustatic change?

Answer 1

Change in the volume of water in the global ocean store

Question 2

What influences eustatic change?

Answer 2

influenced by variations in global temperatures, affecting water in ocean store and it’s density

Question 3

what is isostatic change?

Answer 3

change in the land level- impacts sea level

Question 4

Give 4 physical factors affecting changes in global temperature.

Answer 4

1. variations in earths orbit around the sun- 400000 year cycle
2. variations in amount of energy produced by the sun, 11 year cycle
3. variations in earths tilt, 41,000 year cycle
4. changes in atmospheric composition due to volcanic eruptions

Question 5

why do sea levels fall during glacial periods?

Answer 5

Cooler temperatures, more precipitation in the form snow, so more water stored on land as solid rather than being returned to the ocean store, so sea levels drop.

Question 6

1 degree Celsius fall in global temperatures leads sea levels to fall by

Answer 6

2m

Question 7

Compare the temperatures and sea levels during the Tyrrhenian inter-glacial period and Riss glacial period.

Answer 7

1. Tyrrhenian inter-glacial period- 130,000 years ago, temperatures were 3(degree Celsius) higher than today and sea levels were 20m higher
2. Riss glacial period- 108,000 years ago, temperatures were 7(degree Celsius) lower than today and sea levels dropped by 100m

Question 8

• EWhat are emergent landforms?

Answer 8

Landforms formed by wave processes during times of higher sea levels are exposed when sea levels drop and therefore can be found a distance inland

Question 9

Give 3 examples of emergent landforms often found together

Answer 9

Raised beaches, marine terraces and relic cliffs

Question 10

What are raised beaches?

Answer 10

they are areas of former shore platforms, left at a higher level than coast due to drop in sea level

Question 11

What key features can you find in abandoned cliffs?

Answer 11

Wave cut notches, arches and caves

Question 12

Name one similarity and one difference between Raised beaches, marine terraces and relic cliffs.

Answer 12

They are all essentially formed similarly, by marine erosion during times of higher sea level. But Marine terraces are often at a much larger scale found a distance inland

Question 13

How high is the raised beach at the Isle of Portland?

Answer 13

15m above sea level

Question 14

When was raised beached formed at the Isle of Portland?

Answer 14

Thought to be Tyrrhenian period

Question 15

How was the Portland limestone eroded? AND what were the rates of erosion.

Answer 15

The limestone thought to have been eroded by hydraulic action, exploitation of the bedding planes. Erosion rates considered to be around 1m/year

Question 16

Exposure of emergent landforms to waves has reduced but what 2 processes are they still affected by?

Answer 16

Mass movement and weathering

Question 17

Describe the evidence of peri-glacial conditions at Isle of Portland.

Answer 17

At the top of relic cliff, there is a 1-1.5m layer of frost shattered limestone debris, considered to have formed in the last glacial period as it underwent periglacial conditions. Moreover, there are peri-glacial processes such as cryoturbation due to contortions in fragmented limetsone

Question 18

Explain 3 ways in which climate change may impact emergent landforms.

Answer 18

1. Chemical weathering by carbonation of limestone may increase due to more acidic ocean water
2. Colonisation of marine terraces by marine organisms on the surface, (e.g. Limpets and whelks) may increase biological weathering
3. Rising sea levels, may place emergent landforms at risk of wave processes and perhaps making them more difficult to distinguish