Glacial systems and landscapes Flashcards
Ablation
The loss of mass from the glacier, e.g. meltwater, avalanches, sublimation, evaporation.
Abrasion
Small rocks within the base of the glacier rub against the bedrock.
Accumulation
The addition of mass to the glacier, usually as snow.
Active Layer
The top layer of soil above permafrost, which thaws annually in summer.
Alpine Regions
Areas of low temperature in high altitude, mountainous regions.
Arêtes
- A ridge formed between two corries.
Basal Ice Melting
The weight of a temperate glacier causes meltwater, which will then erode the
bedrock through fluvial erosion
Basal Sliding
Glaciers sliding over bedrock, due to meltwater between the two surfaces.
Blockfields
Rock-strewn landscape caused by extensive frost action.
Cold-Based Glacier
- (Also called Polar Glaciers) The glacier’s temperature remains below zero
degrees, so the base of the glacier remains frozen and moves very little.
Compressional Flow
Ice builds up and thickens due to friction as a glacier travels upwards along
a shallow gradient.
Corries
A round hollow in the side of a hill, widened from an initial smaller hollow by a glacier
within the hollow.
Crushing
The weight of the glacier causes fracturing in the bedrock
Drumlins
When a glacier hits an obstacle that cannot be eroded, deposition from underneath the
glacier builds up behind the obstacle.
Environmental Fragility
An environment is vulnerable or at risk, with low resilience or ability to
adapt to changes.
Erratics
Boulders transported and deposited by a glacier. The type of rock that forms the erratic
will usually differ from the rock types in the surrounding landscape.
Esker
- A long, winding ridge of fluvio glacial deposition.
Extensional Flow
- Ice thins out, creating crevasses, due to an increase in the glacier’s velocity
down a shallow gradient.
Fluvial Erosion
Water within the glacier erodes the base of the glacier over time through:
hydraulic action, attrition, corrosion.
Frost Heave
The freezing and expansion of water beneath the ground, resulting in floor uplift.
Glacial Budget
The difference between accumulation and ablation for a glacier.
Glacial Period
- A period of time of colder average global temperatures causing the growth of ice
cover, glacial advances and sea levels to fall.
Glacial Trough
A U-shaped valley formed from a v-shaped river valley that becomes filled and
eroded over time by a glacier.
Hanging Valleys
A valley with a wall at one end, due to the glacier that filled the valley previously
being low energy.
Holocene Epoch
Our current glacial period of limited ice cover, lasting over 10,000 years.
Ice Wedge
Water infiltrates small cracks in the permafrost and expands on freezing repeatedly
Interglacial Period
A period of time of warmer average global temperatures, resulting in reduced
ice cover, glacial retreat and sea levels to rise.
Internal Deformation
- Glacial movement caused by the weight of the glacier above deforming the
ice.
Kames
Piles of material, sorted due to the differing weight of sediment, left on the valley floor after
a glacier melts.
Milankovitch Cycles
Changes to the tilt and shape of the orbit will affect the average temperature
of the Earth.
Meltwater Channels
Streams of meltwater (melted glacier) formed by higher temperatures.
Moraines
Deposits of eroded material that has been transported by a glacier. Moraines may be
lateral, medial, ground, recessional or terminal.
Nivation
Erosional processes involving snow and ice.
Orbital Eccentricity
How far a planet’s orbit is from being a perfect circle.
Outwash Plain
Material is washed out and deposited due to large volumes of meltwater as a
glacier recedes.
Patterned Ground
Patterned ground is formed through the frost heave of stones in and
underneath the active layer.
Periglacial
Landscapes found at the edge of glacier, polar and alpine regions. Permafrost occurs,
with low precipitation and only highly adapted plant species survive.
Permafrost
Permanently frozen soils throughout the year.
Pingos
A mound produced as ground is forced upwards through frost heave.
Plucking
Rocks on the bedrock are frozen within the glacier. As the glacier moves, the rocks are
pulled from the bedrock and moved.
Polar Regions
Areas of maximum ice sheets and limited vegetation, located at high latitudes on
Earth.
Roches Moutonnées
Rock shaped by a glacier flowing over it and eroding it.
Solifluction
The movement of waterlogged soil, trapped between the active layer and permafrost.
Solifluction Lobes
As the active layer thaws, soil falls down the hillside in tongue-shaped lobes.
Terracettes
Ridges running parallel across a hillside, believed to be created by vegetation
trapping sediment falling loose down the hillside, created through frost heave.
Thermokarst
Marshy, boggy wetlands caused when permafrost melts.
Till Plains
An ice sheet detaches from the main glacier and melts, releasing all loose till and
sediment across the bedrock.
Warm-Based Glacier
- (Also called Temperate Glaciers) Faster travelling glaciers due to basal
meltwater trapped underneath the glacier, acting as lubrication to allow the glacier to move.
