SECTION A - Glaciated Landscapes
8 markers:
Explain how climate change affects the glacial movement for ice sheet/ glacier (8)
- Climate change such as periods of glacials and interglacials influences temperature,
precipitation, and meltwater production: all directly affect glacial movement in both ice
sheets and valley glaciers
- Ice sheet - main movement is through internal deformation
- However, with climate change, parts of the base may warm toward the pressure
melting point, potentially allowing localised basal sliding, especially near the
margins or beneath ice streams.
- In warm-based glaciers, rising temperatures cause increased surface melting,
leading to more meltwater at the base.
- This enhances basal sliding, especially through processes like slippage and
regelation creep, allowing glaciers to move faster
- Climate change can also steepen surface gradients through thinning, promoting
extending flow, which accelerates movement and increases crevassing
Explain the difference between a WBG and a CBG - way they move/size/found (8)
- WBGs and CBGs differ due to their basal temperatures, which influences how they
move, their size, and where they are located.
- WBGs are found in temperate or high-altitude regions such as the Andes or the
Rockies, where surface and basal temperatures are at or above the pressure
melting point.
- This allows for basal sliding as meltwater lubricates the bed. WBGs move mainly by
basal sliding using processes like:
- Slippage (ice slides over bed)
- Regelation creep (ice deforms over obstacles)
- Bed deformation (movement on saturated sediments).
- As a result, they are fast-moving, typically 20–200 metres per year, and highly
dynamic, with frequent seasonal advances and retreats.
- WBGs are usually smaller valley glaciers with steep relief and high erosion rates.
- In contrast, CBGs are found in polar, high-latitude regions such as Antarctica and
interior Greenland, where temperatures are below the pressure melting point
- They are frozen to the bed and move mainly by internal deformation, including:
- Intergranular flow (crystals shifting within ice)
- Laminar flow (ice layers sliding past one another)
- CBGs are very slow-moving (just a few metres per year) and often part of large
continental ice sheets with low relief
- These glaciers are more stable with little erosion and show minimal seasonal
variation in movement.
, 16 markers:
“To what extent are landforms interrelated for an ice sheet?” (16)
Argument: they are interrelated, Laurentide ice sheet which reached 1 km thick in some
places
1. Erosional landforms are interrelated - through glacial advance - “land of 10,000
lakes”, ellipsoidal basin from areal scouring and differential erosion - Oldest rocks lie
in alternating bands of granite (volcanic) and gneiss (metamorphic) - differential
erosion (large ellipsoidal basin) + areal scouring (causing hollows) caused the lakes
to form eg. Upper and Lower red lakes in N. Minnesota , Mountains reduced from
1500m to 500m
2. Depositional landforms are interrelated - through retreat and interglacials
- 4 different lobes- Wadena, Superior, Rainey and Des Moines. retreating -
depositing till, Red= northeast, Gray= northwest - forming deposition
landforms which are interrelated Drumlin fields such as in Otter Tail County -
direction of ice flow - deposited material which aligns with moraines
- Different types of moraines are interrelated - Wadena lobe deposits the
Itasca moraine (terminal) - links to other moraines such as recessional and
lateral moraines
3. Erosional and depositional linked - large rock or boulder that differs from the
surrounding geology/ area - believed to have been transported by glacial action
- Erratics as far as Kansas- 1000km, highlighting extent of ice sheet
- These appear isolated in the location they were deposited in and therefore
whilst they don’t appear interrelated to other landforms they are linked
through the processes and climatic conditions of the ice sheet make it
interrelated
- These erratics may have caused striations along the
“To what extent is human activity more influential on a periglacial landscape than a
glacial landscape”
Argument: both influential but periglacial environments are more sensitive
1. More influential - Alaska pipeline and homes - thawing permafrost - thermokarst
landscapes - destabilises the land - increased solifluction and patterned ground
(disrupted periglacial processes)
- Alaskan pipeline (1300 km from Prudhoe Bay to Valdez) oil is 49℃
2. More influential - Alaska - urban heat island - eg. Barrow 2.2 ℃ warmer than
surrounding area
- Area 1002 in ANWR expected to contain around 12 billion barrels of oil (lots
of activity such as drilling and flaring which releases methane and CO2 into
the atmosphere- enhanced greenhouse effect)
- Thawing permafrost = positive feedback loop - 1600 GT stored globally
8 markers:
Explain how climate change affects the glacial movement for ice sheet/ glacier (8)
- Climate change such as periods of glacials and interglacials influences temperature,
precipitation, and meltwater production: all directly affect glacial movement in both ice
sheets and valley glaciers
- Ice sheet - main movement is through internal deformation
- However, with climate change, parts of the base may warm toward the pressure
melting point, potentially allowing localised basal sliding, especially near the
margins or beneath ice streams.
- In warm-based glaciers, rising temperatures cause increased surface melting,
leading to more meltwater at the base.
- This enhances basal sliding, especially through processes like slippage and
regelation creep, allowing glaciers to move faster
- Climate change can also steepen surface gradients through thinning, promoting
extending flow, which accelerates movement and increases crevassing
Explain the difference between a WBG and a CBG - way they move/size/found (8)
- WBGs and CBGs differ due to their basal temperatures, which influences how they
move, their size, and where they are located.
- WBGs are found in temperate or high-altitude regions such as the Andes or the
Rockies, where surface and basal temperatures are at or above the pressure
melting point.
- This allows for basal sliding as meltwater lubricates the bed. WBGs move mainly by
basal sliding using processes like:
- Slippage (ice slides over bed)
- Regelation creep (ice deforms over obstacles)
- Bed deformation (movement on saturated sediments).
- As a result, they are fast-moving, typically 20–200 metres per year, and highly
dynamic, with frequent seasonal advances and retreats.
- WBGs are usually smaller valley glaciers with steep relief and high erosion rates.
- In contrast, CBGs are found in polar, high-latitude regions such as Antarctica and
interior Greenland, where temperatures are below the pressure melting point
- They are frozen to the bed and move mainly by internal deformation, including:
- Intergranular flow (crystals shifting within ice)
- Laminar flow (ice layers sliding past one another)
- CBGs are very slow-moving (just a few metres per year) and often part of large
continental ice sheets with low relief
- These glaciers are more stable with little erosion and show minimal seasonal
variation in movement.
, 16 markers:
“To what extent are landforms interrelated for an ice sheet?” (16)
Argument: they are interrelated, Laurentide ice sheet which reached 1 km thick in some
places
1. Erosional landforms are interrelated - through glacial advance - “land of 10,000
lakes”, ellipsoidal basin from areal scouring and differential erosion - Oldest rocks lie
in alternating bands of granite (volcanic) and gneiss (metamorphic) - differential
erosion (large ellipsoidal basin) + areal scouring (causing hollows) caused the lakes
to form eg. Upper and Lower red lakes in N. Minnesota , Mountains reduced from
1500m to 500m
2. Depositional landforms are interrelated - through retreat and interglacials
- 4 different lobes- Wadena, Superior, Rainey and Des Moines. retreating -
depositing till, Red= northeast, Gray= northwest - forming deposition
landforms which are interrelated Drumlin fields such as in Otter Tail County -
direction of ice flow - deposited material which aligns with moraines
- Different types of moraines are interrelated - Wadena lobe deposits the
Itasca moraine (terminal) - links to other moraines such as recessional and
lateral moraines
3. Erosional and depositional linked - large rock or boulder that differs from the
surrounding geology/ area - believed to have been transported by glacial action
- Erratics as far as Kansas- 1000km, highlighting extent of ice sheet
- These appear isolated in the location they were deposited in and therefore
whilst they don’t appear interrelated to other landforms they are linked
through the processes and climatic conditions of the ice sheet make it
interrelated
- These erratics may have caused striations along the
“To what extent is human activity more influential on a periglacial landscape than a
glacial landscape”
Argument: both influential but periglacial environments are more sensitive
1. More influential - Alaska pipeline and homes - thawing permafrost - thermokarst
landscapes - destabilises the land - increased solifluction and patterned ground
(disrupted periglacial processes)
- Alaskan pipeline (1300 km from Prudhoe Bay to Valdez) oil is 49℃
2. More influential - Alaska - urban heat island - eg. Barrow 2.2 ℃ warmer than
surrounding area
- Area 1002 in ANWR expected to contain around 12 billion barrels of oil (lots
of activity such as drilling and flaring which releases methane and CO2 into
the atmosphere- enhanced greenhouse effect)
- Thawing permafrost = positive feedback loop - 1600 GT stored globally
