Glaciers Flashcards
Ablation
The removal of surface snow or ice by sublimation, melting or evaporation
Abrasion
Rocks and other materials carried by the sea are picked up by strong waves and thrown against the coastline causing more material to be broken off and carried away by the sea
Accumulation
The addition of mass to the glacier, usually as snow
Bulldozing
When rocks and debris found at the front of the glacier are pushed downhill with the ice
Deposition
The laying down of sediment carried by wind, flowing water, the sea or ice
Englacial debris
Within the ice of a glacier, believed to have been formerly within the ice of a glacier
Erosion
The geological process in which earthen materials are worn away and transported by natural forces such as wind or water
Firn
Snow that is at least one year old and has therefore survived one melt season, without being transformed to glacier ice
Freeze-thaw action/ freeze-thaw weathering/ frost shattering
Occurs when rocks are porous or permeable. Water enters cracks in the rock and when temperatures drop, the ice freezes and expands causing the cracks to widen. The ice melts and water makes its way deeper into the cracks.
Glacial outwash
A plain formed of glaciofluvial deposits due to meltwater outwash at the terminus of a glacier
Nevée
A young, granular type of snow which has been partially melted, refrozen and compacted yet precedes the form of ice
Snout
The lowest end of a glacier
Plucking
As the glacier moves over rock, meltwater freezes into joints or cracks in the rock. When the glacier moves it ‘plucks’ out pieces of rock.
Rotational Slip
The semi-circular motion of a mass of rock and/or soil as it moves downslope along a concave face
Stratified
Dividing sampling into groups
Subglacial debris
Material found at the base of the glacier
Striations
Linear furrows, or linear marks, generated from fault movement
Till
Sediment that has been transported and deposited by or from glacier ice, with little or no sorting by water
Transportation
The movement of material by suspension, solution, traction or saltation
Weathering
The wearing down or breaking of rocks while they are in place
Zone of ablation
The low-altitude area of a glacier/ ice sheet below firn with a net loss in ice due to melting, sublimation, evaporation, ice calving- aeolian processes like blowing snow, avalanche or other ablation
Zone of accumulation
Refers to the area above the firn line, where snowfall accumulates and exceeds the losses from ablation
Formation of a glacier
Snowfalls- compressed so air is squeezed out- this forms firn of nevées- more compression squeezes more air out, forming glacial ice over approximately 20 yrs- the ice moves downhill due to gravity to form a glacier
Bulldozing
The glacier pushes sediment in front of it at its snout
Glacial till
material which has been dropped by a glacier
Stratified
vertical layering/ lines created by annual layers of sediment
Outwash material
dropped by meltwater some distance from the snout
Arête
Where two corries erode back to back
Pyramidal peak
Where 3 or more corries erode back to back
Truncated spurs
Interlocking spurs are chopped off by a glacier leaving steep valley sides
Hanging valley
Where the tributaries used to flow into the main river valley but the main valley got deeper leaving behind the tributary valley
Moraine
Accumulations of rock deposited by a glacier
Drumlins
Small hills made of till that were shaped under a glacier
Erratics
Large blocks of rock which are different to the place where they were dropped by a glacier
4 types of moraine
Terminal, Ground, lateral, medial
National Park
An area of countryside protected for the benefit and enjoyment of people
Honeypot site
A place which attracts a disproportionate number of tourists for its size
