Dynamic Planet Study Document

What are the main types of snow?

The four main types of snow are: individual ice crystals, névé, firn, and glacial ice.

What is névé?

Névé is a granular type of snow that has been partially melted and can contribute to glacier formation.

Define firn.

Firn is a type of snow that has been recrystallized into a denser substance that is denser than névé and eventually becomes glacial ice.

What is the equilibrium-line altitude (ELA)?

The ELA marks the area on a glacier where accumulation is balanced by ablation over a one-year period.

What causes ablation in glaciers?

Ablation is caused by processes such as sublimation, fusion or melting, and evaporation.

Name two key processes involved in glacial flow.

Basal sliding and internal deformation.

How do glaciers flow?

Glaciers flow due to gravity, primarily through basal sliding, internal deformation, and bed deformation.

What is a valley glacier?

A valley glacier is a stream of flowing ice confined within steep-walled valleys, usually following the course of an ancient river valley.

What are ogives?

Ogives are alternating crests and valleys in glacier ice that appear as dark and light bands of ice, linked to the seasonal movement of a glacier.

Define crevasses.

Crevasses are deep cracks or fractures in a glacier formed when ice undergoes brittle deformation due to extreme stress.

What is thermal regime in glacial studies?

The thermal regime is a classification of glaciers based on the temperature at the base, distinguishing between cold-based and warm-based glaciers.

What types of landforms result from glacial erosion?

Erosional landforms include cirques, U-shaped valleys, hanging valleys, arêtes, and horns.

What are terminal moraines?

Terminal moraines are ridges of glacial debris deposited at the end of a glacier.

What is marine ice sheet instability?

Marine ice sheet instability occurs when rising temperatures cause ice sheets that lie below sea level to collapse, a significant issue in West Antarctica.

How are proglacial lakes formed?

Proglacial lakes are freshwater bodies formed behind a moraine or ice dam left by a retreating glacier.

Describe the function of ablation stakes.

Ablation stakes are used to measure the rates of accumulation and ablation on a glacier.