Glaciation

Question 1

What is an ice age?

Answer 1

A long period in time when the earths temperature was reduced resulting in the expansion of continental and polar ice sheets and glaciers.

Question 2

When was the last ice age in Europe?
How thick?
Where from?

Answer 2

Ended about 18,000 years ago, several kilometres thick, spread down from the north as the climate cooled and glaciers filled and eroded the valley.

Question 3

Look at glacier in Europe/uk in notes

Answer 3

*

Question 4

What are interglacial periods?

Answer 4

The warmer periods during the ice age, they often last thousands of years.

Question 5

What does mer de glace mean?

Answer 5

Sea of ice

Question 6

What is a glacier?

Answer 6

A slow moving mass

Question 7

What is glaciation?

Answer 7

The process or state of being covered by ice glaciers or ice sheets

Question 8

How is a glacier formed?

Answer 8

A glacier is ged by new snow high up in the mountains where it is coldest. Over many years the snow becomes compacted to form ice. It then starts to move down hill due to gravity.

Question 9

Name the features of a glacier.

Answer 9

Heavy snowfall
Crevasses
Glacier
Snout
Abrasion
Terminal moraine
Plucking

Question 10

Features glaciation produces?

Answer 10

Corrine
Arêtes
Pyramidal peaks
U shaped valleys
Hanging valleys
Truncated Spurs

Question 11

What are crevasses?

Answer 11

Deep cracks in the ice
They can be metres across and perhaps 5-10m deep
Crevasses form when the ice is stretched as it flows down a steep slope.

Question 12

What is moraine?

Answer 12

Debris like Fragments of rock and stone covering a glacier

It comes from the surrounding mountain slopes as rocks are broken off by processes of erosion

Question 13

What is weathering and erosion?

Answer 13

Freeze-thaw weathering
Water enters cracks in rocks and freezes and expands.
Repeated freeze thaw weathering means cracks in the rock expand until the rock is fractured.

Question 14

What is abrasion?

Answer 14

The moraine frozen into the glacier scours and scrapes the valley sides and floor.

Question 15

What is plucking

Answer 15

The water at the bottom of the glacier freezes into rock on the valley base. As the glacier moves the rock is pulled away from the valley base.

Question 16

What are corries?

Answer 16

A Corrie or cirque is a bowl shaped valley that has been deepened by snow.
Over time, more snow collects in the hollow and the extra weight compresses the snow underneath turning it into ice.
The hollow is deepened and widened by the Corrie glacier through the process of abrasion and plucking.

Question 17

What is an arête?

Eg?

Answer 17

A knife-edge ridge. It is formed when two neighbouring Corrie run back to back. As the glacier erodes Esther side of the ridge, the edge becomes steeper and the ridge becomes narrower.
Striding edge found on helvellyn in the Lake District.

Question 18

What is a pyramidal peak?

Eg?

Answer 18

Formed when three or more corries and arêtes meet. The glaciers have carved away at the top of the mountain creating a sharply pointed summit.
Mont Blanc
Matterhorn
Mount Everest.

Question 19

What is a u shape valley?

Answer 19

Formed by glaciers in mountain valleys and have a characteristic u shape, with steep, straight sides and a flat bottom. They are formed when a glacier travels across and down a slope, carving the valley. When the ice retreats or thaws the valley is often covered with small boulders that were transported within the ice glacial till.

Question 20

What are truncated spurs?

Answer 20

On a u shaped valley the interlocking spurs are cut off by the glacier moving down the valley, they are called truncated spurs

Question 21

Name the five types of moraine.

Answer 21

Recessional moraine - as the glacier recedes it leaves piles of moraine behind.
Ground moraine - material that was at the bottom of the glacier. It is on the valley floor when ice melts. This is also called till.
Lateral moraine - occurs at the sides of the glacier. It is made up of rocks that have been weathered from the valley sides by freeze thaw.
Terminal moraine - material that is left at the snout of the glacier.
Medial moraine - occurs in the centre where two glaciers have joined.

Question 22

What is a drumlin?

How are they formed?

Answer 22

A low oval mound or small hill, typically one of the group, made up of one compacted boulder from past glacial action.
Formed from glacial till. They are elongated features that can reach a kilometre or more in length, 500m in width and over 50m in height.
A collection of drumlins is called a swarm.

Question 23

What is an erratic?

Answer 23

An erratic is a boulder that is different to the bedrock upon which it is sitting. They have been transported and deposited by a glacier. Therefore erratics are useful indicators of patterns of former ice flow.

Question 24

What is an avalanche?

Answer 24

A mass of snow and ice that moves rapidly down a mountain side.

Question 25

How are avalanches caused?

Answer 25

Increase in temperature at the surface causes melted layers which may freeze and form a layer of ice.
Fresh snow falling on this surface can be unstoppable.
Any distribution can cause upper layers of snow to lose grip and begin to slide, causing an avalanche.
Can be triggered by skiers, snowboarders or even a small earthquake.

Question 26

Some impacts of avalanches?

Answer 26

An avalanche can obstruct anything in its path. Roads and railways can be blocked, power supplies cut off and they can tear down trees and ski lifts. A powerful avalanche can destroy buildings.
People can also be killed, 90% of people who die from avalanches trigger themselves. They usually die from a lack of oxygen when buried in snow rather than getting too cold. But they may also suffer from impact injuries and fractures.