Glaciation Flashcards
When did the ice age begin
About 1,000,000 years ago and lasted til about 10,000 years ago
What happened during this time
Temperatures fluctuated and ice advance and retreated four times
What parts of Britain were covered in ice
Northern and eastern
The ice that covered nearly all the UK grew from which ice sheet
The Scandinavian ice sheet which was centred on Sweden and Finland
Where are large glaciers in Europe found
The mountain ranges such as the alps or Pyrenees
How do glaciers travel
They grow and flow down valleys
How much of the earth was covered in ice
30%
What happened since the beginning 2 million years ago
There were 4 vey cold periods
What are ice advances called
Glaciations
When was the last glaciation
70000 years ago and ended 10000 years ago
What were interglacial
Warm periods between glaciations where temperatures could be higher than today
Ice sheets
Huge advances of ice that are several kilometres thick
In Europe ice sheets spread from
The norths as the climate cooled
Ice sheets cover
Vast areas maybe even whole continents
What are some things that could have caused the ice age
•Variations in the sun’s energy. The sun’s output is not constant so during times when it is less, the Earth is cooler.
•Changes in the earth’s orbit so that for certain periods we were further from the sun making the planet colder.
•A massive volcanic eruption- the ash & dust blocking the suns energy
Glaciers
Large rivers of ice that move slowly downhill cane change the shape of the landscape
How do glaciers change the shape of landscapes
Through erosion and deposition
Where do glaciers form
Very cold places where there is lots of snowfall but not all of it melts
How do glaciers form
Regular snowfall but irregular melting leads to lots of different layers of snow lying on top of each other. As the snow layers build up year after year the lowest layers become compacted and compressed until the air is pushed out and the snow turns into ice and this gradually moves down slope under the force of gravity
What are the differences between ice sheets and valley glaciers
Masses of ice which cover large areas of a continent are called ice sheets whilst those which occupy mountain valleys are called valley glaciers.
How much of the earth right covered in ice
10%
When are the biggest glaciers currently found
Antarctic and Greenland
What are smaller glaciers found
High altitudes in various mountain ranger in the lower middle and higher laltitudes
Eg Mont Blanc Canadian rockies or the alps
Ice caps
Extensive sheets of ice . Technically they cover and area smaller than 50000km squared anything bigger and they are an ice sheet
What is anbexample of a glacier
Thé mer de glace
What does net de glacé mean
River of ice
When is the mer de glade found
French alps
Describe the mer de glace
The Mer de Glace is 7km long, 1200 metres wide and up to 200 metres thick.
What speed does the mer de glacé move
About 70m each year
What does a glacier system consist of
Inputs, transfers(flows), stores and outputs
Input
Comes from avalanche s along the sides of the glacier but mainly perception as snow
Storage
Over time snow accumulates and is compressed into ice. The water held in storage is the glacier
Flows/transfers
Under the force of gravity the glacier flows downhill
Output
Meltwater is the main output from a glacier along with some evaporation
Glaciers are formed where
The temperature is cold enough to allow snow accumulate over a period of yesrs
What 2pms is the length of glacier decided into
Accumulation and ablation
Accumulation
When the snow and ice are building up
Ablation zone
Where ice is melting
When does the glacier grow
When more snow falls than melts then accumulation is higher than ablation
When does the glacier retreat
When more snow melts than falls ablation is higher than accumulation
Describe how the glacier ,Ives through zones
All glaciers move slowly down hill. The highest part, where the snow falls and turns to ice, is called the accumulation zone. It is extremely cold here, lots of snow falls and the temperature rarely rises above freezing.
As the glacier moves downhill in starts to warm up and melt. The place where the glacier melts is known as the ablation zone.
How long does a snowflake spend on glacier
Up to 400 years
Describe how a glacier is a solid and liquid
Looks like a solid but behaves like a liquid
It pushes up against an object and is solid enough erode but fluid enough to move around like water in slow motion
How is the glacier able to move
Meltwater lubricates the glacier and helps it slip along the valley bottom often re freezing around rocks and carrying them with it
What process to glaciers carry out
Erosion
Weather material
Deposit
What are the erosion processes
Plucking
Abrasion
Weather process
Freeze thaw weathering
Plucking
This is the tearing away of blocks of rock which have become frozen onto the base and sides of the glacier
When does plucking occur
When rocks and stones become frozen to the base of the glacier and are ‘plucked’ from the ground as the glacier moves
Where does maximum erosion occur
Where the ice is heaviest
When does plucking happen
When glacier ice freezes and sticks to rock
What does plucking do to the back wall
Steepens it
Describe how plucking becomes abrasion
When the glacier moves, large angular pieces of rock are pulled/plucked away with it. These are then used for abrasion
Abrasion
This is the wearing away of the rocks at the base and sides of the glacier by the scouring action of ice containing rocks plucked from the Earth’s Surface. The ice acts rather like an enormous sheet of sand paper.
How does abrasion affect the landscape
This leads to the valley getting steeper, deeper and wider. The bedrock is polished smooth by the ice as it moves across it
What form when rocks scrape/grind the base and sides of the valley
Striations or smooth polish finish
Why are striations important
They show the direction of ice
Describe freeze thaw weathering
Where water enters cracks in rocks , freezes and when it does expands. Repeated freezing and thaw means cracks in the rock expand until, the rock is fractured. Leading to material falling off the glacier or breaking down
Describe weather erosion
Small crack in the rock surface water enters the crack in the rock from rainfall at night temperatures fall and water freezes .the ice expands nearly 10% and put pressure on the rock and eventually causes the rock to split/further and eventually breakthrough 
Plucking is what
The tearing away of of blocks of rock which have become frozen onto the base and sides of glacier. It occurs when rocks and stones become frozen to the base of the glacier and are ‘plucked’ from the ground as the glacier moves
Abrasion is what
Wearing a way of rock at the base sides of the glacier by scoring action of ice containing rocks plucked from the Earth surface. ice acts rather like an enormous sheet of sandpaper 
Corrie
This is a steep sided bowl shaped hollow at the head of a glaciated valley. It is often described as an ‘armchair’ shaped allow
A lake the forms in a corrie is a
Tarn
How is a corrie formed
Snow collects natural hollow on the side of a mountain over time further Snow in the Hollow, the extra weight compressed the snow underneath turning into ice. The hollow was deep and widened by the Corrie glacier through the process of abrasion and plucking the overdeepning leads to armchair and causes rock clip to be formed 
Pyramidal peak
Also known as horns are formed when three or more Corries cut backwards into the same mountain
Famous example of pyramidal peak
Matterhorn(Switzerland/italy)
What is an arête
A steep rocky ridge between two corries. This is a knife edge like ridge between two corries that have eroded back towards each other
How are u shaped valleys formed
As the glacier flows down an old V-shaped valley. As the glacier flows it erodes the sides and bottom of the valley by abrasion and plucking. The valley becomes U shaped with very steep sides and flat bottom
Crevasses
Large cracks in the ice
Describe crevasses
Few metres wide and several metres deep.
Where is the deepest crevasses
Found in Antarctic and Greenland are over 30 metres deep
How are crevasses formed
When the ice is forced to stretch and then crack as it flows down a steep slope
How are crevasses dangerous
Crevasses are extremely dangerous. They open and close as the glacier moves. They are often hidden under fresh snow and skiers and walkers have to watch out for them
What is moraine
Type of landform that is created when a glacier deposits the material hat it has been transporting.
What is moraine made of
It is made up of unsourced angular rocks. It often makes the glacier look dirty
Lateral moraine
Down the side
Medial
Down the middle because 2 glacier have joined
When does deposition occur
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
Where is the material deposited
Either on the valley floor or across lowlands at the foot of highland areas by the ice or meltwater streams
What are deposition features
Moraine and drumlins
What cause deposition terms
Ice melt, water and wind deposition
What are the 4 types of moraine
Ground
Terminal
Lateral
Medial
Terminal moraine
At the snout of glacier
What are drumlins formed from
Boulder clay sometimes called till
What are the two ends of a drumlin
Blunt end and tapered end
What are a collection of dru,links
“Basket of eggs” or drumlin swarm
Describe a drumlin
They are elongated(stretched out) features-egg shaped hills. They can reach a kilometre or more in length, 500 meters or so in width and over 50 metres high
Explain the height of drumlins
One end is quite steep whilst the other end tapers away to ground level
What way did ice flow over drumlins
Steep to ground level
The stoss end is
The steeper of the two ends and used to face the ice flow
Drumlin field
A cluster of dozens to hundreds of similarly shale, sized and oriented drumlins. Also known as a drumlin swarm
Erratics
An erratic is a boulder that is different to the bedrock upon which is sitting they have transported and deposited by a glacier 
What are erratic useful for?
They are useful indicators of patterns of former ice flow 
Give an example of an erratic
Large piece of larvikite rock from Norway find an east Yorkshire beaches 
