Summary

An ice age consists of cold glacial periods and warmer interglacial periods

The causes of the ice ages could be due to reductions in incoming solar radiation e.g. sunspot activity or blockage of incoming solar radiation by such things as volcanic eruptions

Glacial ice forms after many years from compacted snow which turns to firn or neve, then glacial ice as more and more air is squeezed out

Glaciers can be classified into four types: corrie (cirque or cwm) glacier, valley glacier, piedmont glacier, ice sheet (ice cap)

Glaciers, like rivers, behave as a system with inputs, outputs, stores and transfers

The upper part of a glacier where inputs exceed outputs is called the zone of accumulation.

The lower part of a glacier where outputs exceed inputs is called the zone of ablation

The annual budget of a glacier describes the input/output relationships of ice, firn and snow

Amount and type of glacier movement depends on whether the glacier is classified as warm (temperate) or cold (polar)

Glaciers can move by any of four processes: basal sliding, creep, extending-compressing flow and internal deformation