Glaciation

Question 1

How many years ago was 30% of the land covered in ice

Answer 1

18,000 years ago

Question 2

What is an ice age

Answer 2

It when there is a period of time when thick ice sheets cover vast areas of land as the global temperature stays below 0°c

Question 3

What is a glacier

Answer 3

A large body of ice moving down a slope slowly over a wide area of land.

Question 4

What are the 3 processes which glaciation affects

Answer 4

Erosion
Transportation
Deposition

Question 5

How are glaciers formed

Answer 5

They form in very cold places. Lots of snow falls but not all melts. This means lots of layers of different snow lie on top of each other.
The bottom layers of snow get compressed by the top layers. This means that the air is pushed out of the snow getting turned into ice forming a glacier.
The glacier gradually moves down the slope under the force of gravity.

Question 6

What is the difference between an ice sheet and a glacier

Answer 6

Masses of ice which cover Large areas of a continent are called ice sheets, whilest those which occupy mountain valleys are glaciers

Question 7

Countries in Europe that were covered with ice during the ice age

Answer 7

Iceland
All of Ireland
Norway
Sweden
Finland
Denmark

Question 8

What are interglacials

Answer 8

We call times with large ice sheets “glacial periods” (for ice ages) and times without large ice sheets ‘interglacial periods

Question 9

How much of the world is covered in glaciers today

Answer 9

About 10%

Question 10

Where are the biggest glaciers today

Answer 10

In Antarctica and Greenland

Question 11

What does the glacier system consist of

Answer 11

Inputs, transfers (flows) stores and outputs in the same way as a river

Question 12

The glacier system explained short

Answer 12

Come from avalanches along the sides of the glacier, but mainly from precipitation as snow.
Over time snow accumulates and is compressed into ice . The water held in storage is the glacier. Under the force of gravity the glacier flows down hill. Melt water is the main output from the glacier, along with evaporation.

Question 13

What is accumulation

Answer 13

Accumulation happens when the input is bigger that the output on a glacier. In the winter, more is added to the glacier system than is lost. This happens near to the head of a glacier and leads to a zone of accumulation. This can cause the glacier to advance.

Question 14

What is ablation

Answer 14

Ablation is when the output is higher than the input. In the summer and at lower altitudes, more is lost from the glacier system than is added. This leads to a zone of ablation and can cause the glacier to retreat.

Question 15

What are the three main processes that operate in the glacier system

Answer 15

Frost
Shattering
Ablation
Plucking

Question 16

What is frost shattering

Answer 16

Frost shattering describes the action of glacial meltwater on joints, cracks and hollows in rock. During the day the water enters the cracks in a rock.
When the water reaches freezing point the water inside cracks,freezes, expands and causes the cracks to widen.
When the temp rises the water thaws and contracts. This eventually causes rocks to break up.

Question 17

What is abrasion

Answer 17

The moraine frozen into the glacier scours the valley sides and base. This is a sand papering effect, similar to corrosion by a river but on a far larger scale.

Question 18

What is plucking

Answer 18

Water at the bottom of the glacier freezes onto rock on the valley base.as the glacier moves,the rock is pulled away from the valley base. Plucking mainly occurs when the rock is well jointed.

Question 19

What is a corrie

Answer 19

It’s when snow collects in a natural hollow on the side of a mountain over time, further snow collects in the hollow. This is extra weight compresses the snow underneath, turning it into ice.

Question 20

How does a corrie formed step by step (5steps)

Answer 20

1. Snow gathers in a hollow and turns into ice,
   2.material from the base of the hollow is plucked out by the ice and a-braised the hollow to make it deeper
2. Eventually the ice out grows fine hollow and goes down slope due to gravity
3. When the ice melts it leaves a depend hollow called a corrie
4. Sometimes the Corry fills up with water to form a lake this is called a tarn.

Question 21

What is an arête and how is it formed

Answer 21

-An arête is a ‘knife edged’ ridge formed between two corries.
-when two Corries form next to each other and their adjacent walls are eroded backwards until they meet, a narrow and pointed rock ridge is formed. This is often likened to a knife edge, with a near vertical sides and a sharp top edge

Question 22

What is a pyramidal peak and how is it formed

Answer 22

A pyramidal peak is formed when three or more Corries are formed back to back. The Matterhorn in the alps and Mount Everest in the Himalayas are famous pyramidal peaks

Question 23

What are u-shaped valleys

Answer 23

As glaciers move downhill they change v-shaped valleys into u-shaped valleys or glacial troughs. The ice has great erosive power.
Whereas a river creates v-shape valley because it acts mainly in the base of the valley. Glaciers fill the valley and create steep sides and the side bases.

Question 24

Formation of a u-shaped valley

Answer 24

1. Before glaciation a v-shaped valley is formed by a river. During the ice age a glacier moves down this valley.
   2.rocks trapped in the bottom of the ice act like sandpaper wearing away the valley by abrasion.
   3 the glacier deepens, straightens and Widens the valley by abrasion.
2. After the ice melts a u-shaped valley remains

Question 25

What are some characteristics of the u-shaped valley or glacial trough

Answer 25

-hanging valley between two truncated spurs are hanging valleys which have not been eroded as deeply as the main valley.
-misfit stream- the river that flows through the valley after the ice age is described as a misfit stream e.g the river could have never eroded the valley
-interlocking spurs are truncated as the glacier cuts straight through the landscape.
- wide a and flat valley floor.

Question 26

When does deposition occur

Answer 26

Deposition occurs when a rise in temperature causes ice to melt and the glacier is no longer able to carry as much material so it dumps it.

Question 27

What are 3 main landforms created by glacial deposition

Answer 27

-moraines
-drumlins
-erratics

Question 28

What is a moraine

Answer 28

A moraine is a type of landform that is created when a glacier deposits the material (till) that it has been transporting. It is. Made up of unsorted angular rocks

Question 29

What is a drumlin

Answer 29

Drumlins are smooth mounds of deposited material that reach a kilometer or more in length, 500m or so in with and over 50m in height. It is thought they were formed when the ice became over loaded with sediment. A group of drumlins is called a swarm

Question 30

What are striations

Answer 30

These are scratches on material that the glacier is carrying. They give an indication of the direction that the glacier was travelling in.

Question 31

What are erratics

Answer 31

Erratics are large boulders that has been carried out by the glacier and then deposited in an area f different rock type, so they look completely out of place.e