Glaciation Key Terms Flashcards
(56 cards)
What is Ablation?
The process of melting and sublimation by which a glacier loses ice and snow.
What is Accumulation?
The process of snow and ice being added to a glacier, primarily through snowfall.
What is the Active Layer?
The top layer of soil above permafrost that thaws in summer and refreezes in winter, allowing limited biological activity and geomorphic processes.
What is Albedo?
A measure of how much sunlight a surface reflects, ranging from 0 (no reflection) to 1 (total reflection). Surfaces like ice and snow have high albedo, while darker surfaces have low albedo.
What is an Arête?
A sharp knife-edged ridge formed between two glacial corries.
What is Basal Crushing?
The process where rock fragments at the glacier base are ground down by the weight and movement of the ice, producing fine rock flour.
What is Basal Melting?
The melting of ice at the base of a glacier caused by geothermal heat and pressure melting, which contributes to basal sliding.
What is Bed Deformation?
When soft sediments beneath a glacier deform and flow, allowing the overlying ice to move more easily.
What is a Bergschrund?
A crevasse that forms between the moving glacier ice and the stationary ice or firn above it.
What are Braided Rivers?
River channels that split and rejoin multiple times, typically found in meltwater-dominated environments.
What is Continuous Permafrost?
A thick, unbroken layer of frozen ground found in the coldest regions, where the ground remains frozen year-round.
What is a Corrie (Cirque or Cwm)?
A bowl-shaped hollow with a steep back wall, formed by glacial erosion and freeze-thaw weathering, often holding a tarn.
What is Crag and Tail?
A resistant rock (crag) protects softer material behind it, forming a tapering ridge (tail).
What is a Crevasse?
A deep open crack that forms in a glacier due to differential movement.
What is the Cryosphere?
The portions of the Earth’s surface where water is in solid form, including ice sheets, glaciers, ice caps, sea ice, snow cover, and permafrost.
What is Discontinuous Permafrost?
Areas where permafrost occurs in patches, interspersed with unfrozen ground, due to slightly warmer conditions.
What is a Drumlin?
Streamlined, elongated hills of glacial till, formed beneath a glacier and indicating the direction of ice flow.
What are Erratics?
Large rocks or boulders transported and deposited by a glacier far from their source region.
What is an Esker?
Long, winding ridges of sand and gravel deposited by meltwater rivers under a glacier.
What is Firn?
Compacted, granular snow that has undergone partial melting and refreezing but has not yet transformed into glacial ice.
What is a Fjord?
A glacial trough flooded by rising sea levels after ice has melted.
What is Freeze-Thaw Weathering?
The breakdown of rock caused by the repeated freezing and thawing of water within cracks or pores in the rock.
What is Frost Heave?
The upward swelling of soil due to the formation of ice lenses during freezing conditions.
What is Glacial Till?
Unsorted sediment deposited directly by glacial ice.