Glaciated Landscapes- Key Question 1 // How can glaciated landscapes be viewed as a system?

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What is a glacier?
A land based ice mass that is thick enough to flow under its own weight
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What is a glaciated landscape?
Glaciated landscapes have been shaped, at least in part of, by the action of glaciers. It could be a glacier on it now or it could have been in the past (relict)
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What is a valley glacier?
Rivers of ice which flow down from high mountains in river valleys
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What is an ice sheet?
Areas of ice spread out over land and sea, extend for more than 50,000 km2
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Where are glaciers found?
They are found where the temperatures are close to 0 and the altitude is more than 60 degrees north and south of the equator
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What is the present day distribution of glaciers?
Currently, 10% of the earths surface is covered by ice. Out of this 6.9% are ice sheets and 3.1% are glaciers. Ice sheets can be found in places such as Greenland and Antarctica. Glaciers are found in the rocky mountains, Canada and the Andes, Chile.
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What is an ice age?
An extended period of time where the earth experiences a cycle of very cold phases (glacials), interspersed with warmer phases (interglacials)
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What does Glacial mean?
A very cold phase where global temperatures dropped by approximately 5 degrees resulting in the spread of ice
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What does Interglacial mean?
Warm phase where temperatures increased to present level or above
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What was the past distribution of glaciers during the last Pleistocene like?
Approximately 30% of the earths surface was covered with ice. Glaciation of the southern hemisphere was less extensive because of the configuration of the continents. The Laurentide ice sheet covered north america
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What is Accumulation?
The addition or gain of snow and ice to a glacier over time
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What is Ablation?
The loss of ice and snow, especially from a glacier, through melting, evaporation and sublimation
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What is Equilibrium?
A long term balance between inputs and outputs of a system. Amount of ablation= Amount of accumulation
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What is the Accumulation Zone?
Where accumulation exceeds ablation. (higher altitudes)
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What is the Ablation Zone?
Where ablation exceeds accumulation. (lower altitudes)
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What is the Glacial net balance?
The difference between accumulation and ablation. Where you have a +ve net balance, acc>abl. Where you have a -ve net balance, abl>acc
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How do you work out the Glacial net balance?
Accumulation - Ablation = Glacial net balance
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What is the Glacial mass balance?
The difference between the amount of snow and ice Accumulation and the amount of Ablation occurring in a glacier over a one year period
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What is a system?
A set of interrelated elements comprising of components (stores) and processes (links) that are connected together to form a working unit or unified whole
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What are the types of energy involved in the glacial system? (3)
Potential, Kinetic and Thermal
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What is potential energy?
It is stored energy. In terms of a glacier on a mountain it is energy stored in the glaciers height. The higher and heavier the glacier, the more energy is stored
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What is kinetic energy?
The capacity to do work as a result of motion. The heavier the thing is and the faster it moves the more of this energy it has
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What is thermal energy?
The capacity to do work as a result of heat. It is the energy that comes from the movement of atoms in a substance
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What are the 4 types of ablation?
Melting, evaporating, sublimation and calving
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What is a warm based glacier (temperate glaciers)?
Usually have high altitude locations and in places of steep relief. Water is present throughout and acts as a lubricant.
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What is a cold based glacier (polar glaciers)?
Usually found at high latitude locations and in places of low relief. The ice remains frozen at the base, therefore there is little water and movement
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What is the pressure melting point?
The temperature at which ice is at the verge of melting
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What combination of mechanisms does basal sliding involve?
Slippage, relegation and substrate deformation
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What combination of mechanisms does internal deformation involve?
Intergranular slip and laminer flow
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What is the rigid zone?
The upper zone of the glacier where the ice is brittle and breaks. the movement of the rigid zone is due to the movement of the ice below
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What is the plastic zone?
The lower zone of the glacier, where under pressure the ice deforms
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What are the factors affecting the movement of glaciers? (4)
Gradient, thickness of ice, internal temperature of ice and the glacial budget
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What is the weathering called that occurs in a glacier?
Freeze- thaw
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What are the 2 types of erosion that occur in a glacier?
Plucking and Abrasion
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What is freeze- thaw?
Water is confined in rock joints and expands when it freezes, this then causes the rock to break into smaller particles
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What is plucking?
Rocks that have been frozen to the base or the sides of the glacier are plucked as the glacier moves. This leaves behind a jagged landscape
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What is abrasion?
Rocks are rubbed against the sides and base of the glacier. This causes the wearing away of the landscape as the glacier behaves like sandpaper
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What are the inputs of a glacial system? (6)
Potential energy, Thermal energy, Kinetic energy, Rockfall, Avalanches and Snow
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What are the throughputs of a glacier? (6)
Abrasion, Plucking and freeze- thaw (processes). Glacial ice (stores). Debris and Kinetic energy (transfers- flows)
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What are the outputs of a glacier? (8)
Meltwater, evaporation, calving, icebergs, glacial drift, sublimation, debris and thermal energy
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What is a closed system?
These have transfers of energy into and beyond the system boundary, but not matter
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What is an open system?
Where matter and energy can be transferred across the boundary into the surrounding environment
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What is dynamic equilibrium?
A state of balance between continually changing processes
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What is negative feedback?
It acts to minimise or dampen the effect on change. It doesn't go around in a loop instead it starts and ends.
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What is positive feedback?
It acts to reinforce or amplify the effect on change. It does around in a cycle/ loop.
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What are the 4 physical factors that can affect glaciated landscape systems?
Climate, Latitude and longitude, Relief and slope aspect and Geology
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How would temperature affect the mass balance?
High temperatures means more ablation, meaning that the glacier could retreat A variation in temperatures throughout the year or day and night could lead to more freeze- thaw weathering
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How would precipitation affect the mass balance?
High precipitation could mean more accumulation, because the rain can freeze into ice and add to the glacial mass balance
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Other cards in this set

Card 2

Front

What is a glaciated landscape?

Back

Glaciated landscapes have been shaped, at least in part of, by the action of glaciers. It could be a glacier on it now or it could have been in the past (relict)

Card 3

Front

What is a valley glacier?

Back

Preview of the front of card 3

Card 4

Front

What is an ice sheet?

Back

Preview of the front of card 4

Card 5

Front

Where are glaciers found?

Back

Preview of the front of card 5
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