Glaciation and Glacial Landforms

What are alpine glaciers?

Glaciers that form in mountains and valleys

What are the different types of alpine glaciers

• Valley

• Piedmont

• Icefield

• Cirque

• Tidewater

What are the types of glaciers?

• Alpine glaciers

• Ice Sheets (Continental glaciers)

Zone of Accumulation

Area where there is a build up of snow and ice

Equilibrium Line

Boundary between accumulation and ablation

Zone of Ablation

Area where melting and evaporation exceed accumulation (zone of wastage

Label the areas

1. Zone of Accumulation

2. Equilibrium Line

3. Zone of Ablation

Describe the zone of fraction and where it occurs

Occurs on the upper portion of the glacier where ice behaves in a brittle matter

Describe the zone of flow and where it occurs

Occurs on the lower portion of the glacier where ice behaves as a plastic due to overlying mass

Internal Flow

Gradual melting and re-freezing of internal ice structure

Basal Slip

Movement of glacier over the meltwater at the base of the glacier

Causes of U shaped and V shaped valleys

• Glaciers cause U-shaped valleys

• Rivers cause V-shaped valleys

Glacial Drift

General term for materials (gravel, sand, silt, clay) deposited by glacial processes

Glacial Till

Unsorted and unstratified material deposited from glacial processes

What are the different types of moraines?

• Lateral - sides

• Medial - middle

• Terminal - end

Cirque

A bowl shaped depression located at the head of the glacier, where snow accumulated, the underlying earth is slowly eroded away to create a cirque

What happens when a cirque metls?

A tarn lake is created

Crevasses

Are formed when the upper portion of a glacier cracks. Generally formed over sudden drops or changes in elevation.

Plucking

Eroded material gets “stuck” in the ice and moves along with the glacier suspended ice

Glacial Erratic

Larger pieces of plucked material that are left behind during glacial retreat

Striations

As glaciers advance pushing plucked rocks and debris forward the underlying bedrock becomes grooved and worn

Rafted Bedrock

Massive pieces of bedrock broken away from source material and relocated by glacial movement

Fluting

Surficial ridges formed parallel to the ice movement direction

Drumlin

hills of till sediment formed and elongated due to glacial movement

Hummocky Disintegration Moraine

Glacial drift deposited at the toe of a retreating glacier amongst blocks of melting ice resulting in knob and kettle topography

Moraine Plateau

Glaciolacustrine sediments are deposited resulting in large flat-topped area once the meltwater flows away

Linear Disintegration Ridge

Glacial till deposited in crevasses resulting in a net patter of narrow ridges following glacial retreat. Also known as crevasse filling

Glaciofluvial

Erosion or deposition caused by flowing meltwater, from melting glaciers, ice sheets, and ice caps

Esker

Long winding ridge of sand or gravel

Kame Delta

Steep side mound of sand and gravel deposited at the perimeter of a stagnant glacier

Kame terrace

Narrow steep sided ridge with a flat top

Outwash Plain

Fan shape deposit of sand and gravel spread out in front of a glacier by glacial runoff

Glaciolacustrine

Sediments deposited into lakes that have formed due to glacial runoff or where glacial meltwater ponds