EQ2 Flashcards
Névé or firn
Partially melted and compacted snow that survives the year’s ablation season (it can become glacier ice).
Extrusion flow
The theory that glacier ice flows faster at a greater depth.
Equilibrium point
Ablation losses and accumulation gains are balanced within a glacier.
Benchmark glacier
A glacier chosen to be monitored annually for ablation and accumulation.
Basal sliding
The sliding of a glacier over the surface it rests on. Caused by the gradient of the slope and the weight of the glacier’s mass. Comes in two forms: relegation slip and (to be undated)
Internal deformation
A ‘creep’ method found generally in cold based glaciers where the ice crystals orientate themselves in the direction of ice movement. This allows ice crystals to slide past one another.
Intergranular flow
When individual ice crystals deform and begin to move in relation to each other.
Laminar flow
Where individual layers of the glacier move.
Glacial surge
Occurs where instabilities in flow result in a rapid forward movement of the snout of the glacier.
Abrasion
Physical wearing and grinding of a surface through friction and impact by material carried in water or ice.
Plucking.
Erosive process of particle detachment by moving glacial ice. In this process basal ice freezes in rock surface cracks. As the main body of ice moves material around, the ice in the cracks in pulled and plucked out. Also called quarrying.
Fracture and traction.
Results from the crushing effect of the weight of ice passing over rock and any variations in pressure resulting in freeze that action (can aid the plucking process)
Dilation
Happens when overlying material is moved, causing fractures in the rock that are parallel to erosion surfaces as the bedrock adjusts.
Meltwater erosion
Similar to fluvial erosion except meltwater is under hydrostatic pressure and chemical weathering
Supraglacial
Situated or occurring at the surface of the glacier.
