Difference between revisions of "Glaciology" - New World Encyclopedia
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[[Image:glacier.zermatt.arp.750pix.jpg|thumb|right|250px|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.]] | [[Image:glacier.zermatt.arp.750pix.jpg|thumb|right|250px|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''' (from Middle French dialect (Franco-Provençal): ''glace'', "ice"; or Latin: ''glacies'', "frost, ice"; and Greek: λόγος, ''[[logos]]'', "speech" lit. "to talk about ice") is the study of [[glacier]]s, or more generally [[ice]] and natural phenomena | + | '''Glaciology''' (from Middle French dialect (Franco-Provençal): ''glace'', "ice"; or Latin: ''glacies'', "frost, ice"; and Greek: λόγος, ''[[logos]]'', "speech" lit. "to talk about ice") is the study of [[glacier]]s, or more generally [[ice]] and natural phenomena involving ice. It is one of the key areas of polar research. |
− | + | As an interdisciplinary [[earth science]], glaciology integrates [[geophysics]], [[geology]], [[physical geography]], [[geomorphology]], [[climatology]], [[meteorology]], [[hydrology]], [[biology]], and [[ecology]]. The impact of glaciers on humans adds the fields of [[human geography]] and [[anthropology]]. Glaciology also includes glacial history and the reconstruction of past glaciation. The presence of ice on [[Mars (planet)|Mars]] and [[Europa (moon)|Europa]] brings in an extraterrestrial component to the field. A person who studies glaciers is called a ''glaciologist''. | |
− | == | + | ==Types== |
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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. | 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. | ||
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==Glacial deposits== | ==Glacial deposits== | ||
===Stratified=== | ===Stratified=== | ||
− | ; Outwash sand/gravel : from front of glaciers, found on a plain | + | ; Outwash sand/gravel: from front of glaciers, found on a plain |
− | ; [[Kettle (geology)|Kettles]] : block of stagnant ice leaves a depression or pit | + | ; [[Kettle (geology)|Kettles]]: block of stagnant ice leaves a depression or pit |
− | ; [[Esker]]s : steep sided ridges of gravel/sand, possibly caused by streams running under stagnant ice | + | ; [[Esker]]s: steep sided ridges of gravel/sand, possibly caused by streams running under stagnant ice |
− | ; [[Kame]]s : stratified drift builds up low steep hills | + | ; [[Kame]]s: stratified drift builds up low steep hills |
− | ; [[Varve]]s : alternating thin sedimentary beds (coarse and fine) of a [[proglacial lake]]. Summer conditions deposit more and coarser material and those of the winter, less and finer. | + | ; [[Varve]]s: alternating thin sedimentary beds (coarse and fine) of a [[proglacial lake]]. Summer conditions deposit more and coarser material and those of the winter, less and finer. |
===Unstratified=== | ===Unstratified=== | ||
− | ; [[Till]]-unsorted : (glacial flour to boulders) deposited by receding/advancing glaciers, forming moraines, and drumlins | + | ; [[Till]]-unsorted: (glacial flour to boulders) deposited by receding/advancing glaciers, forming moraines, and drumlins |
− | ; [[Moraine]]s : (Terminal) material deposited at the end; (Ground) material deposited as glacier melts; (lateral) material deposited along the sides. | + | ; [[Moraine]]s: (Terminal) material deposited at the end; (Ground) material deposited as glacier melts; (lateral) material deposited along the sides. |
− | ; [[Drumlin]]s : smooth elongated hills composed of till. | + | ; [[Drumlin]]s: smooth, elongated hills composed of till. |
− | ; [[Ribbed moraine]]s : large subglacial elongated hills transverse to former ice flow. | + | ; [[Ribbed moraine]]s: large subglacial elongated hills, transverse to former ice flow. |
==See also== | ==See also== |
Revision as of 20:16, 6 August 2008
Glaciology (from Middle French dialect (Franco-Provençal): glace, "ice"; or Latin: glacies, "frost, ice"; and Greek: λόγος, logos, "speech" lit. "to talk about ice") is the study of glaciers, or more generally ice and natural phenomena involving ice. It is one of the key areas of polar research.
As an interdisciplinary earth science, glaciology integrates geophysics, geology, physical geography, geomorphology, climatology, meteorology, hydrology, biology, and ecology. The impact of glaciers on humans adds the fields of human geography and anthropology. Glaciology also includes glacial history and the reconstruction of past glaciation. The presence of ice on Mars and Europa brings in an extraterrestrial component to the field. A person who studies glaciers is called a glaciologist.
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 valleys of mountainous areas and forms a tongue of ice moving towards the plains below. Alpine glaciers tend to make the topography more rugged.
- Continental - an ice sheet found today, only 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, where the formation of ice is faster than its removal.
- Wastage or Ablation, where the sum of melting and evaporation (sublimation) is greater than the amount of snow added each year.
Movement
- Ablation
- wastage of the glacier through sublimation, ice melting and iceberg calving.
- Arête
- an acute ridge of rock where two cirques abut.
- Bergshrund
- crevasse formed near the head of a glacier, where the mass of ice has rotated, sheared and torn itself apart in the manner of a geological fault.
- Cirque, corrie or cwm
- bowl shaped depression excavated by the source of a glacier.
- Creep
- adjustment to stress at a molecular level.
- Flow
- movement (of ice) in a constant direction.
- Fracture
- brittle failure (breaking of ice) under the stress raised when movement is too rapid to be accommodated by creep. It happens for example, as the central part of a glacier movinges faster than the edges.
- Horn
- spire of rock formed by the headward erosion of a ring of cirques around a single mountain. It is an extreme case of an arête.
- Plucking/Quarrying
- where the adhesion of the ice to the rock is stronger than the cohesion of the rock, part of the rock leaves with the flowing ice.
- Tarn
- a lake formed in the bottom of a cirque when its glacier has melted.
- Tunnel valley
- The tunnel is that formed by hydraulic erosion of ice and rock below an ice sheet margin. The tunnel valley is what remains of it in the underlying rock when the ice sheet has melted.
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
- alternating thin sedimentary beds (coarse and fine) of a proglacial lake. Summer conditions deposit more and coarser material and those of the winter, less and finer.
Unstratified
- Till-unsorted
- (glacial flour to boulders) deposited by receding/advancing glaciers, forming moraines, and drumlins
- 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.
- Ribbed moraines
- large subglacial elongated hills, transverse to former ice flow.
See also
ReferencesISBN links support NWE through referral fees
- Benn, Douglas I., and David J. A. Evans. 1998. Glaciers & Glaciation. London: Arnold. ISBN 0340584319.
- Bennett, Matthew, and Neil F. Glasser. 1996. Glacial Geology: Ice Sheets and Landforms. Chichester: Wiley. ISBN 0471963453.
- Hambrey, M. J., and Jürg Alean. 2004. Glaciers. 2nd ed. Cambridge, UK: Cambridge University Press. ISBN 978-0521828086.
- Hooke, Roger LeB. 2005. Principles of Glacier Mechanics. 2nd ed. Cambridge, UK: Cambridge University Press. ISBN 978-0521836098.
- Knight, Peter. 1999. Glaciers. Cheltenham: Stanley Thornes. ISBN 0748740007.
External links
- Snow, Ice, and Permafrost. Geophysical Institute, University of Alaska Fairbanks. Retrieved August 6, 2008.
- Arctic and Alpine Research Group. University of Alberta. Retrieved August 6, 2008.
- International Glaciological Society. Retrieved August 6, 2008.
- Glaciers online. swisseduc.ch. Retrieved August 6, 2008.
- World Data Centre for Glaciology, Cambridge, UK. Retrieved August 6, 2008.
- National Snow and Ice Data Center, Boulder, Colorado. Retrieved August 6, 2008.
- Global Land Ice Measurements from Space. Retrieved August 6, 2008.
- North Cascade Glacier Climate Project. Retrieved August 6, 2008.
- Centre for Glaciology. University of Wales, Aberystwyth. Retrieved August 6, 2008.
- Welcome to the Home of Deep Glaciology. Caltech. Retrieved August 6, 2008.
- Glaciology. University of Washington. Retrieved August 6, 2008.
General subfields within the earth sciences |
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Atmospheric sciences | Geodesy | Geology | Geophysics | Glaciology |
Hydrology | Oceanography | Soil science |
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Biogeography · Climatology & paleoclimatology · Coastal/Marine studies · Geodesy · Geomorphology · Glaciology · Hydrology & Hydrography · Landscape ecology · Limnology · Oceanography · Palaeogeography · Pedology · Quaternary Studies |
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