Glacier Formation and Movement

Flashcards covering key concepts of glaciology, including processes of glacier formation, movement types, erosion, and the effects of glaciers on landscapes.

Glacier Formation Process

The transformation of snow to ice, occurring through snow accumulation, compression, and air removal leading to dense, blue glacial ice.

Firn

Granular, partially compacted snow that is an intermediate stage between snow and glacial ice.

Conditions for Glacier Formation

Cold temperatures below freezing most of the year, sufficient snowfall, and accumulation of snow faster than it melts.

Accumulation

The addition of snow or ice to a glacier, which includes processes such as snowfall and avalanches.

Wastage (Ablation)

The loss of ice from a glacier through melting, sublimation, and calving.

Internal Deformation

A movement type of glaciers where ice crystals slide over each other in parallel planes due to gravity and pressure.

Basal Sliding

A movement type where the glacier slides over bedrock, often aided by meltwater.

Plucking

A glacial erosion process where meltwater seeps into cracks in rocks, freezes, and breaks them apart for the glacier to carry away.

Abrasion

A glacial erosion process where rocks embedded in ice scrape against bedrock, creating smooth and striated surfaces.

Till

Unsorted, unlayered sediment deposited directly by a glacier.

Stratified Drift

Sorted and layered sediment deposited by meltwater.

Terminal Moraine

A ridge of till deposited at the furthest advance of a glacier, marking its edge.

Drumlins

Streamlined hills of till shaped by the movement of ice.

Eskers

Long, winding ridges of sand or gravel formed by subglacial rivers.

Erratics

Large rocks transported away from their source by glacial action, differing from the surrounding bedrock.

Cirques

Bowl-shaped depressions at mountain heads where glaciers form.

Arêtes

Sharp ridges that form between two cirques.

Horns

Pointed peaks formed by erosion from multiple cirques, such as the Matterhorn.

Glacial Impacts

Changes to drainage and sea level caused by glaciers, including new valley formation, river rerouting, and sea level rise due to melting.