INTRODUCTION TO

GLACIERS

1. Basics and definitions

2. Formation of glacier ice

3. Glacier mass balance

4. Types of glacier

Snow compaction ultimately forms hexagonal ice crystals

Snow appears

white, but high-

density glacier

ice appears blue

Present-day snowline LGM snowline

Source: Broecker & Denton, 1990.

Accumulation zoneEquilibrium line

Ablation zone

COLDER

WARMER

Alpine glacier profile and mass

balance. Source: Christopherson, 2003, p. 526.

Firn/equilibrium line

Mer de Glace,

French Alps.

Recent behaviour of

twenty mountain glaciers

worldwide. Source: IPCC, 2001.

Pitztal Glacier, Austria. Source: National Geographic February 2006.

Area of surface melt on the Greenland ice sheet, 1992

and 2002. Source: Konrad Steffen, University of Colorado,

http://cires.colorado.edu/science/groups/steffen/

McCall Glacier, Alaska, 1958.

Source: National Snow and Ice Data Center glacier rephotography collection.

McCall Glacier, Alaska, 2003.

Source: National Snow and Ice Data Center glacier rephotography collection.

Glacier classification systems:

1. Morphology:

Continental glaciation:

Ice sheet/cap/dome

Ice shelf

Alpine glaciation:

Cirque/corrie/cwm glacier

Valley glacier

2. Temperature: warm-based vs. cold-based

Topography of the

Greenland ice sheet

ETH/CU research camp on the Greenland Ice Sheet(photo by Konrad Steffen)

Digital elevation model of Vatnajokull, Iceland

Quelccaya Ice Cap, Peruvian Andes

Map source: USGS

Quelccaya Ice Cap, Peruvian Andes(Source: Ohio State University)

The Antarctic ice sheet: a continental glacier.Source: University of Tokyo.

The Antarctic ice sheet: under-ice topography.Source: University of Tokyo.

Nunataks poking through the East Antarctic

Ice Sheet (Source: British Antarctic Survey)

Ice shelves

Antarctica without

the ice shelves(Source: USGS)

Perspective view of the Ross Ice Shelf,

Antarctica (Source: USGS)

Glacier classification systems:

1. Morphology:

Continental glaciation:

Ice sheet/cap/dome

Ice shelf

Alpine glaciation:

Cirque/corrie/cwm glacier

Valley glacier

2. Temperature: warm-based vs. cold-based

Cirque glacier in the

Annapurna massif,

Nepal

The Western

Cwm, Khumbu

icefall and

Khumbu glacier,

Mount Everest (Source: Joe Simpson,

Dark Shadows Falling)

Everest

Khumbu

Icefall

Western

Cwm

Lhotse

Khumbu

Glacier

Cirque glaciers feeding the Mer de Glace, French Alps

Another valley glacier: Aletschgletscher, Swiss Alps.

Chickamin Glacier, southeast Alaska, 1941(Source: NSIDC)

Glacier classification systems:

1. Morphology:

Continental glaciation:

Ice sheet/cap/dome

Ice shelf

Alpine glaciation:

Cirque/corrie/cwm glacier

Valley glacier

2. Temperature: warm-based vs. cold-based

Pressure melting point- ice and pressure.Source: Clowes and Comfort, 1982.