Glacial Systems and Landscapes Flashcards
Accumulation
Addition of mass to a glacier
Ablation
Loss of mass from the glacier
(Meltwater, avalanches, evaporation)
Glacial budget
Difference between total accumulation and ablation for one year
Positive glacial budget
Accumulation exceeds ablation, so the glacier advances
Open system
Matter and energy can be exchanged across the system’s boundaries
Closed system
Only energy (not matter) can be exchanged across the boundary
Positive Feedback
The inputs of a process are amplified by the outputs
Negative Feedback
The inputs of a process are nullified by the outputs
Glacier
Large mass of ice constantly moving under the pressure of its own weight
Mass Balance
Difference between total accumulation and ablation for any one time
Snout
End of the glacier where melting occurs
Basal Slippage
Layer of meltwater acting as a lubricant to help ice slide over bedrock
Macro scale glaciers
Over 50,000 km^2
Meso scale glaciers
Under 50,000 km^2
Dynamic Equilibrium
State of balance where process causing the balance are continual (always occurring)
Polar Environments:
Location
High latitudes at the poles (66 degrees North and South) at Arctic Circle and Antarctic Circle
Polar Environments:
Temperature
North Pole:
Summer 0 degrees C
Winter -40 degrees C
South Pole:
Summer -30 degrees C
Winter -60 degrees C
Polar Environments:
Climate, Vegetation and Soils
Below freezing temperatures
Little rainfall (<100 mm per year)
Only adapted mosses and lichen grow
Soil is low in nutrients and limits further plant growth
Alpine Environments:
Location
High altitude, mountainous regions
Alpine Environments:
Temperature
Temps fluctuate annually
Summer above 10 degrees C
Winter -15 degrees C
Alpine Environments:
Climate, Vegetation and Soils
More snowfall in winter than polar environments
Adapted animals live at high altitudes
Adapted nutrient rich vegetation grows in soil
Pressure melting point (PMP)
Temperature at which ice melts under pressure. The deeper the ice means more pressure on the base from mass above, creating more friction and a lower PMP
Periglacial Environments: Location
On the edge of cold environments - polar, alpine
Areas of permanently frozen ground (permafrost) - continuous, discontinuous, sporadic, isolated
Active layer thaws in summer
Periglacial environments: Temperature
Temps consistently below freezing
Summer temps thaws active layer
Periglacial Environments: Climate, vegetation and soils
Vegetation more than polar regions - only highly adapted plants
Poor soils and slow nutrient cycle - waterlogged soil in summer
Deoxygenated plants - nutrients leached out
Warm based glaciers
Alpine, fluctuating warmer temps and lots of melt water (erosion from basal sliding and internal deformation)
Summer - base temps below 0 degrees
Winter - -10 degrees
Cold based glaciers
Polar - consistently dry and cold, little meltwater
Internal deformation only, no basal sliding
Summer - <-10 degrees base temp
Winter - <-10 degrees base temp
