Glaciers Revision Notes

Open system

A system that can have inputs added to it, such as mass and energy in a glacial system.

Annual glacier mass balance

The difference between accumulation and ablation over one year.

Accumulation zone

The top of the glacier where there is least melting, leading to a positive mass balance.

Ablation zone

The lower section of a glacier (snout) where negative mass balance occurs due to loss of mass.

GPE

Gravitational potential energy, which transforms to kinetic energy during the downslope movement of glaciers.

Diagenesis

The process through which glacier ice forms from low density snow, compressing into firn, and then into glacial ice.

Constrained glaciers

Smaller glaciers limited by terrain, such as valley and corrie glaciers.

Unconstrained glaciers

Larger glaciers that can erode the surrounding landscape, including ice sheets and ice caps.

Warm based glaciers

Glaciers that are formed at high altitudes and low latitudes, moving rapidly and having basal temperatures above the pressure melting point (PMP).

Cold based glaciers

Glaciers formed at high latitudes with low altitudes, moving slowly due to basal temperatures below PMP.

Glacial erosion processes

Includes plucking (where rocks are frozen to the glacier and pulled off) and abrasion (where debris in the glacier wears away at the underlying rocks).

Freeze-thaw weathering

A physical weathering process where water enters cracks, expands when frozen, and breaks apart the rock.

Chemical weathering

A weathering process that involves chemical reactions between water and minerals in rocks, often increasing in warmer temperatures.

Corries

Glacial landforms that are eroded hollows caused by plucking and abrasion, often forming a bowl shape.

Aretes

Sharp ridges formed between two neighboring glacier-corrie systems due to erosion.

Roche moutonnee

An obstacle shaped by glaciers where one side is smooth (stoss) and the other jagged (lee) due to erosion processes.

Moraines

Depositional landforms created from till, including terminal, lateral, and recessional moraines.

Erratics

Rocks that have been transported and deposited by glaciers to areas where they do not typically occur.

Drumlins

Streamlined hills made by glacial deposits, with a steep side (stoss) and a shallow tail (lee) side.

Mass balance

The relationship between accumulation and ablation which determines whether a glacier advances or retreats.