DISTRIBUTION AND TYPES OF GLACIERS

(i) Present Day-Distribution of Glaciers

The distribution of glaciers today is controlled by climate. They exist where temperatures are cold enough to allow the accumulation of ice each year to exceed the process of ablation (growth of glacier occurs where accumulation > ablation). Today, glaciers may be found in:

1. Areas of HIGH LATITUDE - where annual temperatures are low and there is a high albedo, reflecting large amounts of solar radiation back to space - these conditions are ideal for glacier formation. Examples include: Antarctica and Greenland.

2. Areas of HIGH ALTITUDE - atmospheric pressure falls with increasing altitude, causing an expansion in the volume of air and decreasing temperatures. The Alps, Andes and Himalayas all have glaciers. Glaciers can even exist at the equator above 5000m due to the conditions at high altitude (e.g. Cotopaxi Volcano - Ecquador)

(ii) Types of Glaciers

There are a number of different types of glaciers, mainly classified according to size / the area they occupy. Types of Glaciers include:

• Ice Sheets
• Ice Caps
• Mountain Ice Caps
• Ice Field
• Valley Glacier
• Corrie Glacier
• Piedmont Glacier
• Ice Shelf

You should make sure you are clear about the distinction between these different glaciers and learn named examples and their locations (see class work and powerpoint below)

THE GLACIAL SYSTEM

Glaciers are systems, they represent the balance between inputs; outputs; stores and transfers.

(See Glacier System Diagram handout completed during lesson - blank copy below)

INPUTS - these include snow, precipitation, rock debris, heat energy;

OUTPUTS - these include ablation (formation of meltwater); sublimation of snow and ice; calving; sediment deposits and heat energy;

TRANSFERS / PROCESSES - diagenesis (snow transformed to ice); transport; erosion and deposition;

STORES - in the form of snow, ice, meltwater and debris (stored in, on and under the ice)

Remember - Glaciers form when it is cold enough for snow to remain frozen throughout the year - enabling accumulation to occur - and overtime diagensis as the layers of snow are compressed (see previous notes on ice formation).

Glacier System Diagram:

Lesson Resources (Handouts and Extra Links)

Handouts / Lesson Resources:

Types of Glacier (Powerpoint Presentation) - if you haven't got powerpoint on your computer you may need to download the free powerpoint viewer from the Microsoft site (click here)

Types of Glacier (Worksheet - pdf file)

Glacier System Diagram (pdf file)

Suggested Background Reading:

Geobytes Glaciation Web (See Classification and Distribution of Glaciers Sections)

Types of Glaciers (external link)

What types of Glaciers are there? (external link)

Glacial Systems and Mass Balance (a brief introduction) (external link)