Glaciated Landscapes Can Be Viewed As Systems Flashcards
Inputs
Kinetic energy from wind and glacier movement
Thermal energy from heat of the sun
Potential energy from material on slopes
Material from processes of weathering
Mass movement and deposition
Processes/ throughputs
Stores such as ice,water and debris accumulations
Flows and transfers such as the movement of ice
Water and debris and downslope under gravity
Outputs
Glacial and wind erosion from rock surfaces
Evaporation
Sublimation
Meltwater
Flow and energy
What is a system
Interrelated objects that have relationships between them
Examples
What are glacial systems
Open systems which means matter can cross the boundary of the system to the environment
Combination of inputs,processes and outputs form distinctive landforms from erosional to depositional created by natural geomorphic processes and the reflection upon human activity
Transfer material within a few days to millennia
Equilibrium
Inputs and outputs are equal
The rate at which snow and ice are added to a glacier equals the rate at which snow and ice melt = glacier is the same size
Answer
A glacier can be seen as an open system with interrelated objects of inputs, processes, stores and outputs connected and functioning together as a unit. Equilibrium is reached when the inputs such as snow and ice fall are equal to the outputs of ablation and sublimation of snow and ice.
Inputs can include Kinetic energy, gravitational potential and precipitation in the form of direct and blown snow fall followed by heavier avalanches, aeolian deposits and rock fall from mass movement . Along with energy also provided by solar radiation and geothermal heat these inputs contribute to glacial accumulation zone within the upper reaches of the glacier if ablation is not occurring at the same or at a quicker rate therefore the mass balance would be positive and lead to glacial advance.
Erosional processes occurring through ice movement under the influence of gravity such as plucking by the action of ablation and re-freezing. Also, abrasion can accumulate debris from the valley floor and upland areas particularly when the glacier is at its highest rate of movement. This can include shaping erosional landforms such as striations,arêtes and hanging valleys.
Outputs occur in the lower levels can include glacial and aeolian erosion from rock surfaces causing melting, sublimation and the carving of glacial and fluvio -glacial sediments. If these outputs are increasing faster than the inputs in the ablation zone is likely sustain leading to the glacier retreating up valley.
Equilibrium is the idealistic state for the glacier and if it is not achieved the glacier will undergo self- regulation to restore known as dynamic equilibrium. The system produces it’s own response as an example of negative feedback. Seasonal variations occur within the glacial budget with accumulation exceeding ablation in the winter and ablation exceeding accumulation in the summer months. Therefore, it can be possible with varying annual and seasonal weather conditions and longer periods of climate changes for some advance to the glacier even in a year when the net budget is negative and some retreat when it is positive. The act of gravity can lead to the glacier moving across the equilibrium line appearing it is advancing when it is retreating.
