Glacial Landscapes

Question 1

Describe the formation of a pyramidal peak

Answer 1

During a period of glaciation, snow gathers in hollows on a mountain-side. As the snow builds up, the ice compacts and three or more corrie glaciers form

Due to the weight of the ice and gravity, the corrie glaciers begin to move. the glaciers move forward slowly, eroding the landscape beneath, making the hollows bigger

Ice sticking to the backwall pulls away blocks as glacier moves. This is known as plucking. Over time, the erosion of the backwall causes the corries to cut into the mountain-side further

The erosion results in a sharp pyramidal peak with radiating arêtes. An example Helvellyn in the Lake District

Question 2

Describe the formation of a hanging valley

Answer 2

During a period of glaciation, snow occupies a tributary river valley.

As the snow builds up the ice compacts and a glacier forms

Due to the weight of the ice and gravity, the glacier begins to move

The tributary glacier moves forward slowly, feeding into the main glacier. The glacier erodes the landscape beneath

As the glacier moves, the processes of abrasion and plucking are at work.

Over time, these processes result in the widening and deepening of the valley, giving a characteristic u- shape.

Tributary glacier is unable to erode the land as much as the main glacier so when the glaciers melt, the tributary valley is left hanging high up above the main glacial trough

Question 3

Describe the formation of a glacial trough

Answer 3

During a period of glaciation, a glacier occupies a former v-shaped valley. As the snow builds up, the ice compacts and a glacier forms

Due to the weight of the ice and gravity, the glacier begins to move. It is unable to wind around the interlocking spurs like a river does

As the glacier moves, the processes of abrasion and plucking are at work.

Over time, these processes result in the widening and deepening of the valley, producing steep sides called truncated spurs, and a flat valley bottom

Question 4

What is abrasion?

Answer 4

Abrasion occurs when the rocks carried along the bottom and side of the glacier wears away the sides and base of the valley

Question 5

What is plucking?

Answer 5

Plucking occurs when the ice sticks to the rock and pulls out loose fragments as the glacier moves forward

Question 6

Name all of the lower glacial features

Answer 6

Hanging valley
Truncated spurs
Glacial trough

Question 7

Name all of the upper glacial features

Answer 7

Arete
Tarn
Pyramidal peak
Corrie

Question 8

What are some features of a corrie

Answer 8

Steep backwall
Rock lip at the front of the corrie
Often has a circular lake, but not always

Question 9

Describe the formation of a corrie

Answer 9

During a period of glaciation, snow gathers in a small hollow in a mountain-side. As the snow builds up it becomes compressed and turns into glacial ice

Due to the weight of the ice and snow, the ice begins to move, forming a glacier. It is lubricated by water at the base. As the ice moves forward it does so in a circular motion known as a rotation slip

Ice sticking to the backwall pulls away blocks as glacier moves. This is known as plucking.

Loose rocks from freeze-thaw weathering and plucking become embedded in the ice which then scape of the bottom of the corries by erosion

After the ice melts, a deep circular hollow with a steep backwall is left behind. This is known as a corrie. Often a circular lake forms in the centre of a corrie, known as a tarn

Question 10

Why do corries normally face N/NE/E/SE?

Answer 10

The sun rises in the east and spends most of teh day in the south. This means that when the corry was formerly a glacier, the south and the west sides wouldn’t have as much time to build up and would melt more than the north and east side.

Question 11

Why does a glacier deposit?

Answer 11

• The ice melts
• When the ice is overloaded with material (not enough energy to transport it all)
• When it hits an obstacle

Question 12

What is glacial till?

Answer 12

Broken rock fragments

• Unsorted
• Angular (due to FTW)
• Also known as boulder clay

Question 13

What is glacial outwash?

Answer 13

Sandy and gravel material deposited by melting ice

• sorted (larger ones near snout, smaller ones further away)
• rounded (due to attrition)

Question 14

What are moraines?

Answer 14

They are piles of glacial till that are carried and deposited by a glacier

Question 15

What are the different types of moraine?

Answer 15

Lateral moraine
Medial moraine
Ground moraine
Terminal moraine
Recessional moraine

Question 16

What is a lateral moraine?

Answer 16

Piles of material deposited at the side of the glacier

Question 17

What is a medial moraine?

Answer 17

Piles of material deposited along the centre of the valley floor. (Formed when 2 lateral moraines join up)

Question 18

What is a ground moraine?

Answer 18

Piles of material left behind by a melting glacier spread over a wide area (forming a hummocky surface)

Question 19

What is a terminal moraine?

Answer 19

A semi-circular mound of material extending across a valley which was dropped at the snout of the glacier-the further point reached by the ice

Question 20

What is a recessional moraine?

Answer 20

Piles of material in narrow ridges across the valley-showing where the ice is receding from

Question 21

Describe the formation of a lateral moraine

Answer 21

During a period of glaciation, a glacier occupies a former v-shaped valley.

The glacier moves slowly through the valley due to gravity and the sheer weight of the ice

High up on the valley sides, above the glacier, freeze thaw weathering takes place

Repeated freezing and thawing weakens the rock and eventually it will drop down onto the glacier. Lots of fragments of rock are deposited and accumulate at the side of the glacier. This is known as lateral moraine

Question 22

What is freeze thaw weathering?

Answer 22

Water enters cracks in rocks. When temperatures drop (usually at night), this water freezes and expands. this places pressure on the crack. When the temperature rise, usually during the day, the ice melts. This reduced the pressure on the crack

Question 23

What are erratics?

Answer 23

Large boulders that have been transported and deposited far away

Question 24

What are some of the characteristics of a drumlin?

Answer 24

• A low, egg-shaped hill
• 30-40 metres high
• 300-400 metres long
• blunt end, tapered end

Question 25

Describe the formation of a drumlin

Answer 25

During a period of glaciation, a glacier fills a valley and slowly moves into lowland areas

At this point, the glacier is overloaded with material and melting is taking place

If the ice hits any small obstacle, such a s a resistant outcrop of rock/sediment, the ice will deposit some of its material

Most of the deposition occurs around the upstream and of the obstacle forming a brunt end which has a steeper slope

As the glacier moves slowly forward around the obstacle, it moulds further material on the downstream side creating a tampered end which is more gently sloping.

Question 26

What are the economic uses of glaciated areas?

Answer 26

Farming
Forestry
Tourism
Quarrying

Question 27

What sort of economical impacts are tourists are tourists having on North Wales

Answer 27

Lots of employment however it is seasonal and low-paid

Extremely high house prices

Price of goods are higher because of tourists

Question 28

What sort of social impacts are tourists having on North Wales?

Answer 28

• Increased traffic, congestion and less parking
• Employment opportunities can prevent out-migration
• Ghost village as lots of homes are 2nd homes

Question 29

What sort of environmental impacts are tourists having on North Wales?

Answer 29

• Footpath erosion, vegetation is tramples and destroyed and soil underneath is vulnerable
• Litter, BBQs and bonfires ruin landscape
• Water sports-noise pollution, fuel spills, waves erode the shoreline

Question 30

What are some management strategies to manage the impact of tourism?

Answer 30

Provision of litter bins

Manage water sports-permits and certain boats banned (Llyn Tegid)

Information boards

Footpath maintenance-good signposting and repair with hard wearing stone

Question 31

Facts about Snowdonia

Answer 31

1 million people walk Snowdon

91% arrive by car

Tourism worth £400M per year

10M visitors every year

Question 32

What are scree slopes?

Answer 32

Loose pieces of sharp rock lying at the foot of a rocky slop

Formed by freeze-thaw weathering

Question 33

What are misfit streams?

Answer 33

They are rivers that now appear to be too small for its valley

Resulting from a valley being enlarged and broadened by glaciation

Question 34

What is a rouche moutonee?

Answer 34

Ice smoothened rock with a steeper jagged side facing down valley

Resistant rock remains after ice abrasion on the ice-direction facing side and plucking on the lee side

Question 35

What are striatations?

Answer 35

Thin parallel scratches on rock surfaces

Formed by ground moraine in the ice which is dragged along the surface of the rock

Question 36

Explain the formation of a ribbon lake

Answer 36

During a period of glaciation, a glacier fills a v-shaped valley.

Due to the weight of the glacier and gravity, the glacier moves slowly through the valley.

Processes that are involved are plucking and abrasion.

Over time, the valley becomes wider and deeper and sometimes overdeepens the valley floor.

This creates a ribbon lake. An example of this would be in the Lake District