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Lateral moraine on a glacier joining the Gorner Glacier, Zermatt, Switzerland. The moraine is the high bank of debris in the top left hand quarter of the picture. For more explanation, click on the picture.Glaciology is the study of glaciers, or more generally the study of ice and natural phenomena that involve ice. The word glacier is derived from the Latin glacies, meaning ice or frost.
Glaciology is an interdisciplinary earth science that integrates geology, climatology, meteorology, hydrology, biology, and ecology. The discipline also forms a part of physical geography. The presence of ice on Mars and Europa brings in an extraterrestrial component to the field.
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Overview
Areas of study within glaciology include glacial history and the reconstruction of past glaciation patterns, effects of glaciers on climate and vice versa, the dynamics of ice movement, the contributions of glaciers to erosion and geomorphology, lifeforms that live in the ice, and so forth.
Unsurprisingly, glaciology is one of the key areas supported by polar research.
Types
There are two general categories of glaciation which glaciologists distinguish: alpine glaciation, accumulations or "rivers of ice" confined to valleys; and continental glaciation, unrestricted accumulations which once covered much of the northern continents.
- Alpine - ice flows down the valley of mountainous areas and forms an apron of moving ice onto the plains below. Alpine glaciers tend to make the topography more rugged.
- Continental - an ice sheet found only in in high latitudes (Greenland/Antarctica), thousands of square kilometers wide and thousands of meters thick. These tend to smooth out the landscape.
Zones of glaciers
- Accumulation
- Wastage
Movement
- Ablation
- wastage through evaporation and melting
- Bergshrund
- crevasse formed at the head of a glacier, where it breaks away from the mountain face.
- Fracture (30-60m thick)
- brittle fracturing creates crevasses due to central part of glacier moving faster than sides/floor.
- Flow
- plastic due to extreme pressure.
- Plucking/Quarrying
- moving glacier picks up large block of stone and transports them, sometimes up to a mile.
- Cirques
- bowl shaped depression where the glacer started and has now melted away.
- Tarn
- lake that forms in the cirque floor
- Horn
- spire of rock formed by the headward erosion of a ring of cirques around a single mountain
- Arěte
- a number of cirques gnaw into a ridge from opposite sides (become jagged)
Glacial Deposits
Stratified
- Outwash sand/gravel
- from front of glaciers, found on a plain
- Kettles
- block of stagnant ice leaves a depression or pit
- Eskers
- steep sided ridges of gravel/sand, possibly caused by streams running under stagnant ice
- Kames
- stratified drift builds up low steep hills
- Varves
- thin sedimentary beds (coarse to fine), summer deposits more material and in the winter, less.
Unstratified
- Till-unsorted
- (glacial flour to boulders) deposited by receding/advancing glaciers, forming moraines, and drumlines
- Moraines
- (Terminal) material deposited at the end; (Ground) material deposited as glacier melts; (lateral) material deposited along the sides.
- Drumlins
- smooth elongated hills composed of till.
References
- Hambrey, Michael and Jürg Alean. Glaciers 2nd ed. Cambridge University Press, 2004. ISBN 0-521-82808-2
- Benn, Douglas I. and David J. A. Evans. Glaciers and Glaciation. London; Arnold, 1998. ISBN 0-340-58431-9
See also
External links
- International Glaciological Society
- World Data Centre for Glaciology, Cambridge, UK
- National Snow and Ice Data Center, Boulder, Colorado
- Global Land Ice Measurements from Space, USGS
- Centre for Glaciology, University of Wales
- Caltech Glaciology Group
- Glaciology Group, University of Copenhagen
- Institute of Low Temperature Science, Sapporo
- National Institute of Polar Research, Tokyo