Glaciated Landscapes
OCR AS/A Level Geography Example Case Studies
Table of Contents
Valley glacier ............................................................................................................. 2
Snowdonia, Wales, United Kingdom ........................................................................................................... 2
Ice sheet.................................................................................................................... 4
Laurentide Ice Sheet, Minnesota, USA ........................................................................................................ 4
Human activity in a periglacial landscape ................................................................... 6
Prudhoe Bay, Alaska, USA .......................................................................................................................... 6
Human activity in a glaciated landscape ..................................................................... 8
Grand Dixence Dam, Switzerland ............................................................................................................... 8
1
,Snowdonia
BACKGROUND
Type of glacier Valley glacier
Location North Wales, United Kingdom
PHYSICAL FACTORS CLIMATE
Most recent glacial Devensian- 110,000 to 10,000 years ago
period in the UK (2) Last glacial was 13,000 to 10,000 years ago
Last Glacial 18,000 years ago
Maximum (LGM) (2) Formed Welsh ice cap- up to 1km thick
Influence on corries Cirque glaciers formed in cwms
(e.g. Cwm Idwal)/ Glacial ice needed to erode the hollow and steep edges
aretes (e.g. Y Gribin) through abrasion and plucking
(5) Cold conditions weather steep backwall through freeze-
thaw and frost-shattering
9 cirques formed along Western flank of Nant Ffrancon
Aretes form between corries
Influence on glacial Extended periods of cold temperatures needed to create
trough (Nant glacial ice
Ffrancon) (2) Cirque glaciers formed in cwms, feeding main valley
glacier in the Nant Ffrancon
Influence on other Extended periods of cold temperatures needed to create
landforms glacial ice, otherwise no glacial landforms would form
ASPECT & RELIEF
Influence on corries Aspect and relief determines direction of glacial
(e.g. Cwm Idwal)/ movement, therefore determining the location and
aretes (e.g. Y Gribin) direction of landform
Influence on Roche Aspect and relief determines direction of glacial
moutonée (2) movement, therefore determining direction of landform
Steeper relief = faster glacial movement = more erosion
to form Roche moutonée
GEOLOGY
Geology of High ground associated with igneous rocks
Snowdonia (2) Low ground associated with weaker mudstones
Geology of cirques 7 cirques carved from mudstone/ weak silty sandstones
(2) 6 have sidewalls of resistant igneous rocks
Influence on corries Made of highly resistant bedrock
(e.g. Cwm Idwal)/ Geology determines how deep the hollow gets
aretes (e.g. Y Gribin) Geology affects steepness and height of arete
(4) e.g. Y Gribin is very sharp and tall so it is formed from very
resistant rock
2
, Influence on Roche Area of more resistant rock (igneous extrusion) in an area
moutonée of less resistant rock (siltstone) needed, otherwise Roche
moutonée would not form
LANDFORM INTER-
RELATIONSHIPS
Cwm Idwal (corrie) Materials plucked and weathered from backwall of corrie
and Y Gribin (arete) Erosion steepens Y Gribin
(3) Materials fall transforming GPE to KE, becoming ‘tools’
for abrasion in Cwm Idwal
Cwm Idwal (corrie) Llyn Idwal tarn formed in an interglacial when melted
and Llyn Idwal (tarn) glacial ice water sits in hollow of Cwm Idwal
Cwm Idwal (corrie) Terminal moraine formed at the foot of Cwm Idwal
and terminal moraine Loss of energy so deposition of material
(2)
Corries and Nant 16 cwms (corries) line the Nant Ffrancon valley
Ffrancon (glacial During glacials, small cwms would feed main trough
trough) (3) During interglacials, not always as connected
Roche moutonnée Small strip of more resistant rock running through Nant
and Nant Ffrancon Ffrancon valley enabled formation of a Roche moutonée
(glacial trough)
Truncated spurs and Powerful erosive force of glacier in main Nant Ffrancon
Nant Ffrancon valley created truncated spurs
(glacial trough)
During interglacials… Few connections; only geographically connected
CHANGES OVER
TIME
Within minutes… Rockfall might occur in corries, on aretes or pyramidal
peaks
Within months… (4) Seasonal changes can speed up chemical and biological
weathering
Seasonal changes to glacier budget and mass balance
mean that erosion and deposition rates vary
Winter = more ice, so glacier advances
Glacial advancement can disturb previously deposited
sediments (e.g. moraine) or glaciofluvial sediments
Within years… (2) Glacial erosion and deposition can create landforms
Long term climate change can cause ice sheet
advance/retreat
Within thousands of Long term climatic changes
years… (3) Valley glaciers can become ice sheets and vice versa
Retreat and removal of a glacier can leave a post-glacial
landscape
Within millions of Long term shifts in Earth’s orbit (Milankovitch cycles) can
years… (3) cause repeated advance/retreat of ice sheets
Shifts in tectonic activity, such as continental drift/
presence of volcanoes can influence geodiversity and ice
sheet formation
Sedimentary rocks can appears as vertical strips as they
are moved
3
OCR AS/A Level Geography Example Case Studies
Table of Contents
Valley glacier ............................................................................................................. 2
Snowdonia, Wales, United Kingdom ........................................................................................................... 2
Ice sheet.................................................................................................................... 4
Laurentide Ice Sheet, Minnesota, USA ........................................................................................................ 4
Human activity in a periglacial landscape ................................................................... 6
Prudhoe Bay, Alaska, USA .......................................................................................................................... 6
Human activity in a glaciated landscape ..................................................................... 8
Grand Dixence Dam, Switzerland ............................................................................................................... 8
1
,Snowdonia
BACKGROUND
Type of glacier Valley glacier
Location North Wales, United Kingdom
PHYSICAL FACTORS CLIMATE
Most recent glacial Devensian- 110,000 to 10,000 years ago
period in the UK (2) Last glacial was 13,000 to 10,000 years ago
Last Glacial 18,000 years ago
Maximum (LGM) (2) Formed Welsh ice cap- up to 1km thick
Influence on corries Cirque glaciers formed in cwms
(e.g. Cwm Idwal)/ Glacial ice needed to erode the hollow and steep edges
aretes (e.g. Y Gribin) through abrasion and plucking
(5) Cold conditions weather steep backwall through freeze-
thaw and frost-shattering
9 cirques formed along Western flank of Nant Ffrancon
Aretes form between corries
Influence on glacial Extended periods of cold temperatures needed to create
trough (Nant glacial ice
Ffrancon) (2) Cirque glaciers formed in cwms, feeding main valley
glacier in the Nant Ffrancon
Influence on other Extended periods of cold temperatures needed to create
landforms glacial ice, otherwise no glacial landforms would form
ASPECT & RELIEF
Influence on corries Aspect and relief determines direction of glacial
(e.g. Cwm Idwal)/ movement, therefore determining the location and
aretes (e.g. Y Gribin) direction of landform
Influence on Roche Aspect and relief determines direction of glacial
moutonée (2) movement, therefore determining direction of landform
Steeper relief = faster glacial movement = more erosion
to form Roche moutonée
GEOLOGY
Geology of High ground associated with igneous rocks
Snowdonia (2) Low ground associated with weaker mudstones
Geology of cirques 7 cirques carved from mudstone/ weak silty sandstones
(2) 6 have sidewalls of resistant igneous rocks
Influence on corries Made of highly resistant bedrock
(e.g. Cwm Idwal)/ Geology determines how deep the hollow gets
aretes (e.g. Y Gribin) Geology affects steepness and height of arete
(4) e.g. Y Gribin is very sharp and tall so it is formed from very
resistant rock
2
, Influence on Roche Area of more resistant rock (igneous extrusion) in an area
moutonée of less resistant rock (siltstone) needed, otherwise Roche
moutonée would not form
LANDFORM INTER-
RELATIONSHIPS
Cwm Idwal (corrie) Materials plucked and weathered from backwall of corrie
and Y Gribin (arete) Erosion steepens Y Gribin
(3) Materials fall transforming GPE to KE, becoming ‘tools’
for abrasion in Cwm Idwal
Cwm Idwal (corrie) Llyn Idwal tarn formed in an interglacial when melted
and Llyn Idwal (tarn) glacial ice water sits in hollow of Cwm Idwal
Cwm Idwal (corrie) Terminal moraine formed at the foot of Cwm Idwal
and terminal moraine Loss of energy so deposition of material
(2)
Corries and Nant 16 cwms (corries) line the Nant Ffrancon valley
Ffrancon (glacial During glacials, small cwms would feed main trough
trough) (3) During interglacials, not always as connected
Roche moutonnée Small strip of more resistant rock running through Nant
and Nant Ffrancon Ffrancon valley enabled formation of a Roche moutonée
(glacial trough)
Truncated spurs and Powerful erosive force of glacier in main Nant Ffrancon
Nant Ffrancon valley created truncated spurs
(glacial trough)
During interglacials… Few connections; only geographically connected
CHANGES OVER
TIME
Within minutes… Rockfall might occur in corries, on aretes or pyramidal
peaks
Within months… (4) Seasonal changes can speed up chemical and biological
weathering
Seasonal changes to glacier budget and mass balance
mean that erosion and deposition rates vary
Winter = more ice, so glacier advances
Glacial advancement can disturb previously deposited
sediments (e.g. moraine) or glaciofluvial sediments
Within years… (2) Glacial erosion and deposition can create landforms
Long term climate change can cause ice sheet
advance/retreat
Within thousands of Long term climatic changes
years… (3) Valley glaciers can become ice sheets and vice versa
Retreat and removal of a glacier can leave a post-glacial
landscape
Within millions of Long term shifts in Earth’s orbit (Milankovitch cycles) can
years… (3) cause repeated advance/retreat of ice sheets
Shifts in tectonic activity, such as continental drift/
presence of volcanoes can influence geodiversity and ice
sheet formation
Sedimentary rocks can appears as vertical strips as they
are moved
3
