Glaciation Flashcards
What is negative feedback?
The process that occurs is counteracted by an opposing process, causing the effects to cancel each other out and nothing changes
What is accumulation? (Systems and processes)
The addition of mass to the glacier
Mainly occurs at higher altitudes at the source
What is internal deformation? (Ice movement)
Stress builds up within the glacier, allowing the ice to behave with plasticity and flow.
Involves ice crystals moving in the same direction of the glacier movement and slides past each other.
What is basal sliding ? (Ice movement)
Lower levels of ice are under a great deal of pressure and combined with friction, it results in melting.
Meltwater acts as a lubricant which causes it to flow rapidly
What is albedo?
How reflective different parts of the planet are
What is a corrie? (Glaciation formation)
An armchair shaped rock hollow with a steep back wall and an over-deepened basin with a rock tip.
With water, it would be called a Tarn
What is compressional flow? (Ice movement)
Occurs when there is a reduction in the gradient of the valley floor
This leads to the deceleration & a thickening of the ice mass
Ice erosion is at its maximum at such point
What does ‘feedback’ mean?
When one of the elements in the system changes and the equilibrium is upset
What factors impact the ice flow ?
Gravity
Temp
Thickness
Bedrock
How does snow get into a glacier system ?
Direct snowfall
Blown snow
Avalanches from slopes surrounding the glacier
These inputs are known as accumulation
How is mass lost from the glacier ?
Either by melting and evaporation, or carving of ice blocks or icebergs
These are known as ablation.
What is ablation? (Systems and processes)
The loss of mass from the glacier
This includes meltwater, avalanches, sublimation and other processes
What is the glacial budget ? (Systems and processes)
The mass balance of a glacier e.g. the difference between accumulation and ablation
What is a positive glacial budget ? (Systems and processes)
When accumulation exceeds ablation so the glacier is advancing
What is a negative glacial budget? (Systems and processes )
Ablation exceeds the accumulation so the glacier is retreating
What is a feedback loop?
Type of chain reaction. One process leads to another process and so on.
There is two feedback loops: positive and negative.
What is a positive feedback?
When a process occurs and another one occurs. This starts a chain reaction which heightens the first process.
Give an example of positive feedback
Temp rise
Permafrost melts
Carbon dioxide is released
Greenhouse effect
Give an example of negative feedback
Temp rise
Permafrost melts
More plants to take in C02
Greenhouse effects lessens
Temp fall
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Where are polar environments located? (nature and distribution)
Located at the poles (high latitudes) within the Arctic circle (66°N) and the Antarctic (66°S)
How much of the earth is covered by ice?
10%
What is the polar climate like ? (Nature)
Long winters with temps below freezing
Often windy, little precipitation (average 100mm)
Scarce vegetation and there’s no soil as it’s made up if vegetation
What is frost shattering?
When water goes into the cracks and expands (by 9%)
What is the climate like in glacial environments?
Soil is present but they are usually covered in snow/ice
Some vegetation is present e.g. small shrubs
There is high snowfall in winter, as a result it accumulates more than what melts in the summer
What is niviation?
When snow creates a hollow and weathers it
What are two ways that ice erodes ?
Plucking
Abrasion
What is ablation till?
Till from when the glacier has melted
What is lodgement Till?
Till from underneath the glacier
How does the glacier transport material?
Supraglacial - top
Englacial - in
Subglacial - bottom
What are the 5 ways in which ice moves ?
Rotational
Extensional
Compressional
Basal sliding
Internal deformation
What is terminal moraine?
Where the snout was previously
What is lateral moraine?
It marks the point where the side of the glacier used to be
What landscapes does erosion create?
Corries, Arêtes, pyramid peaks and U shaped valleys
What is medial moraine ?
When two laterals have came together
What landscapes does depostion create?
Till plains, moraine (ablation till)
drumlins (lodgement till)
and erractics
You won’t get deposition without erosion
True or false?
True
What landscapes does water (fluvioglacial ) create ?
Eskers, kames, outwash plains
These are usually at the bottom of the glacier in low altitudes and the till is sorted
What landscapes does ice create ?
Drumlins lodgement till
Moraine ablation till
