Glaciation Flashcards
What is a cold environment?
Areas of land permanently covered by ice. They are covered by glaciers, ice sheets and have frozen soil/rock. The temperature is constantly below freezing.
What is latitude?
The distance from the equator.
Why do temperatures drop the further away you are from the equator?
Due to the curvature of the earth.
Why are the geographical poles colder than other areas?
Sunlight has to pass through a greater distance of atmosphere. At the earth’s surface, the rays are further spread out resulting in a loss in energy and temperature.
What is altitude?
The height above sea level.
Why do locations at higher altitudes have colder temperatures?
At higher altitudes, the air is under less pressure which means heat is less well maintained.
How does the sun heat up the air?
Air is heated up into the atmosphere when sunlight heats up the land. The further you are away from land, the less warming it receives.
How much does the temperature decrease per 100m?
-1°C
What is continentality?
The distance from the ocean or sea.
Why can coastal areas become warmer in winter?
The world’s oceans and sea take a long time to warm up in comparison to land. But when the sea has warmed up, it retains its heats for much longer.
Why do places in the middle of continents become colder in winter?
They do not receive the warming affect of the sea and will be colder, but warmer in summer.
What is a glacier?
A glacier is a huge mass of ice that slowly moves over land.
How does a glacier form?
When there is a build up of snow over a number of years.
Where are glaciers found?
They can be found at altitude or sea level.
What happens in the input?
As the snow in the glacier becomes increasingly compacted, it turns from powder snow to dense, blue ice.
What else provides input?
When avalanches from surrounding mountain sides provide inputs to the glacial system
What happens in the process?
The weight of the compacted ice with gravity results in the glacier slowly moving downhill.
What happens to the valley during the process?
The moving glacier transports sediment that has dropped onto it, so the valley gets eroded
What comes out from the output?
Ice and meltwater - together with large amounts of sediment
What are the two zones that a glacier can be divided into?
The accumulation zone and the ablation zone
What is the accumulation zone?
This is where there are inputs into the glacial budget
What is the ablation zone?
This is where there are outputs from the glacial budget
What are some examples of inputs in the accumulation zone?
Avalanches, rock from the mountains and snowfall
What are some examples of outputs in the ablation zone?
Heat from the sun, icebergs, rocks, evaporation and meltwater
What occurs in both zones?
Gravity
Why do glaciers advance?
When the accumulation is greater than the ablation
Why do glaciers retreat?
When the ablation is bigger than the accumulation
When do glaciers advance?
In winter due to higher amounts of snowfall and limited melting
When do glaciers retreat?
In summer due to the rapid melting of ice
What is plucking?
Plucking is when meltwater from a glacier freezes to the base rock and lumps of cracked and broken rock. When the ice advances downhill, rock is plucked from the back wall.
Why does abrasion occur?
Abrasion happens when rocks, which have frozen to the base and the back of the glacier, scrape the bedrock.
What can be used to describe abrasion?
Sandpaper
What is freeze-thaw weathering?
Freeze-thaw is when meltwater/rain gets into cracks in the bedrock. At night the water freezes, expands and causes the cracks to get larger, eventually breaking away.
