glacial systems and processes

accumulation

1) The addition of mass (precipitation such as snow) to the glacier

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2) Mainly occurs at higher altitudes at the source of the glacier

ablation

1)The loss of mass from the glacier

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2)Includes meltwater, avalanches, sublimation, evaporation and other processes

glacial budget

1) the mass balance of a glacier

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2) the difference between accumulation and ablation

positive glacial budget

1) shows accumulation exceeds ablation

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2) so the glacier is advancing

negative glacial budget

1) shows ablation exceeds accumulation

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2) so the glacier is retreating

natural systems

1) glaciers are these systems

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2)this means that there are specific interactions with their development and sustaining that allow glaciers to work

concept of natural systems

1) something enters the system which allows for processes to occur

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2)eventually leading to something leaving the system

open system

1) there are inputs from outside the system’s set area

closed system

all the inputs and processes occur within the system’s set area

inputs

1) addition/accumulation to the glacier

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2)precipitation such as snow or hail are inputs to the glacier→ as well as avalanches from other areas entering the system

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3)Debris that has been eroded can also fall into a glacier’s system→ consequently can be transported and deposited elsewhere

outputs

1) things that leave the glaciers system→ usually in form of meltwater

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2)All ablation processes are outputs

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3) Calving is form of this

energy

1) Glaciers all have vary amount of energy→ depends on their MASS, ENVIRONMENT and COMPOSITION

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EXAMPLE: a glacier with more meltwater underneath it will move faster

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2)Glacial energy is usually in the form of kinetic energy as the glacier moves→allows erosion to occur

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3)Gravity allows the glacier to have energy→ forces the glacier downhill

stores

1) are the mass that glaciers hold

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2)Majority of stores within the glaciers are ice, but sediment from erosion and meltwater from lakes/channels also contribute to stores

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3) 3 types of store:

>Subglacial

>Englacial

>Supraglacial

flows

1)occurs in glaciers through the transfer of mass or energy

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2) There are flows in mass and energy from ice on the glacier to meltwater leaving the glacier

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3) the glacier also moves through flows such as compressional flow

dynamic equilibrium

1)refers to a state of balance

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2)this balance is dynamic when the processes causing the balance is continual (always occurring)

feedback loops

1) is a type of chain reaction

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2) Where one process leads to another process, leading to another process, and so on

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2)two types of feedback loops: Positive and Negative

positive feedback loops

1)a process occurs

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2) Which causes another process to occur

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3)Which starts a chain reaction that heightens the first process

negative feedback loops

1) the process that occurs is counteracted by an opposing process

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2) Causing the effects to cancel each other out and nothing to change

mass balance

the difference between accumulation and ablation

calving

1)is a common output

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2)is when large pieces of glacier break off at the snout (the end)

three types of stores

1) Subglacial

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2)Englacial

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3) Supraglacial

subglacial

underneath the glacier

englacial

within the glacier

supraglacial

on top of the glacier

example of dynamic equilibrium

>even if the glacier is constantly gaining inputs and losing outputs

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>if the amount of these are the same, the mass of the glacier does not change annually

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>and the glacier is at a dynamic equilibrium

equilibrium line

1)The area where mass gain = mass loss