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.]]
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[[Image:glacier.zermatt.arp.750pix.jpg|thumb|right|300px|Lateral moraine on a glacier joining the Gorner Glacier in Zermatt, Switzerland. The moraine is the high bank of debris on the left side of the image.]]
  
'''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 that involve ice.  
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'''Glaciology''' is the study of natural forms of [[ice]], particularly [[glacier]]s, and phenomena related to ice. It includes the study of how glaciers are formed and depleted, how they move, and how they affect the physical landscape, the [[climate]], and living [[organism]]s. It is one of the key areas of polar research. It also involves research into glacial history and the reconstruction of past glaciation, thus providing insights into the [[ice age]]s. The apparent presence of ice on [[Mars (planet)|Mars]] and [[Jupiter]]'s moon [[Europa (moon)|Europa]] brings in an extraterrestrial component to the field.
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{{toc}}
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Thus, glaciology is an interdisciplinary [[earth science]], integrating [[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]]. A person who studies glaciers is called a ''glaciologist.''
  
Glaciology is an interdisciplinary [[earth science]] that 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]]. The presence of ice on [[Mars (planet)|Mars]] and [[Europa (moon)|Europa]] brings in an extraterrestrial component to the field.  
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== Etymology ==
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The word ''glacier'' can be traced to the Middle French dialect (Franco-Provençal) term ''glace,'' meaning "ice," derived from the [[Latin]] term ''glacies,'' meaning "frost" or "ice." The word "glaciology" is formed by combining this root with the Greek word λόγος ''([[logos]])'', meaning "speech" or "word."
  
==Overview==
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==Types==
Areas of study within glaciology include glacial history and the reconstruction of past glaciation. A glaciologist is a person who studies glaciers. Glaciology is one of the key areas of polar research.
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The process of glaciation is placed in two general categories, described below.
  
==Types==
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* '''Alpine glaciation:''' It corresponds to accumulations or "rivers of ice" confined to valleys. As ice flows down the slopes of mountainous areas, it forms a "tongue" moving toward the plains below. Alpine glaciers tend to make the [[topography]] more rugged.
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.
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* '''Continental glaciation:''' It corresponds to unrestricted ice sheets that once covered much of the northern continents but are now found only at high latitudes, such as in [[Greenland]] and [[Antarctica]]. The sheets are thousands of square kilometers wide and thousands of meters thick. They tend to smooth out the landscape.
*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==
 
==Zones of glaciers==
*Accumulation, where the formation of ice is faster than its removal.
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*Accumulation zone: A zone where ice is formed faster than it is removed or lost.
*Wastage or Ablation, where the sum of melting and evaporation (sublimation) is greater than the amount of snow added each year.
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*Wastage or Ablation zone: A zone where the sum of melting and evaporation ([[sublimation]]) of ice is greater than the amount of snow added each year.
  
==Movement==
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==Glacial movements and their effects==
; [[Ablation]] : wastage of the glacier through sublimation, ice melting and iceberg calving.
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[[Image:Striding Edge.jpg|thumb|right|250px|Striding Edge, an arête viewed from [[Helvellyn]] with the corrie [[Red Tarn]] to the left and Nethermost Cove to the right.]]
; [[Arete (landform)|Arête]] : an acute ridge of rock where two cirques abut.
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; [[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.
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* [[Ablation]]: In glaciology, ablation means wastage (depletion) of a glacier (or ice or iceberg) through such processes as sublimation, melting, and iceberg calving.
; [[Cirque (landform)|Cirque]], [[Cirque|corrie or cwm]] : bowl shaped depression excavated by the source of a glacier.
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* [[Arête]]: An arête is a thin, almost knife-like, ridge of [[Rock (geology)|rock]] that is typically formed when two [[glacier]]s erode adjacent, [[U-shaped valley]]s. It may also be formed when two glacial cirques erode headwards toward each other.
; [[Creep (deformation)|Creep]] : adjustment to [[Stress (physics)|stress]] at a [[Molecule|molecular]] level.
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* [[Bergshrund]]: A crevasse formed near the head of a glacier, where the moving ice has torn itself apart from stationary ice, in the manner of a geological fault.
; [[Fluid mechanics|Flow]] : movement (of ice) in a constant direction.
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* [[Cirque (landform)|Cirque]] (coombe, combe, or corrie): A bowl-shaped depression excavated by the head of a glacier.
; [[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.
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* [[Creep (deformation)|Creep]]: The adjustment or deformation of solid material under the influence of [[Stress (physics)|stress]]es.
; [[Pyramidal peak|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.
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* [[Fluid mechanics|Flow]]: The movement (of ice) in a constant direction.
; [[Plucking (glaciation)|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.
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* [[Fracture]]: The breaking of ice under stress, especially when movement is too rapid to be accommodated by creep. It happens, for example, as the central part of a glacier moves faster than its edges.
; [[Tarn (lake)|Tarn]] : a lake formed in the bottom of a cirque when its glacier has melted.
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* [[Pyramidal peak|Horn]]: It is a 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.
; [[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.
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* [[Plucking (glaciation)|Plucking]] (or quarrying): Plucking is a process by which a glacier erodes chunks of bedrock. When the [[adhesion]] of ice to the rock is stronger than the [[cohesion]] of the rock, part of the rock leaves with the flowing ice.
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* [[Tarn (lake)|Tarn]]: It is a lake formed at the bottom of a cirque when the glacier has melted.
 +
* [[Tunnel valley]]: It is a deep, narrow valley with a U-shaped cross-section, formed by the erosion of rock when the edge of an ice sheet advances up a slope.
  
 
==Glacial deposits==
 
==Glacial deposits==
 
===Stratified===
 
===Stratified===
; Outwash sand/gravel : from front of glaciers, found on a plain
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* Outwash sand/gravel: This is material derived from the front of glaciers, found on a plain.
; [[Kettle (geology)|Kettles]] : block of stagnant ice leaves a depression or pit
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* [[Kettle (geology)|Kettles]]: A 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
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* [[Esker]]s: These are steep-sided ridges of gravel/sand, possibly caused by streams running under stagnant ice.
; [[Kame]]s : stratified drift builds up low steep hills
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* [[Kame]]s: The 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.
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* [[Varve]]s: They are 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
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* [[Till]]-unsorted: Ranging from glacial flour to boulders, it is 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.
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* [[Moraine]]s: They include 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.
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* [[Drumlin]]s: They consist of smooth, elongated hills composed of till.
; [[Ribbed moraine]]s : large subglacial elongated hills transverse to former ice flow.
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* [[Ribbed moraine]]s: They are large, subglacial elongated hills, transverse to former ice flow.
  
 
==See also==
 
==See also==
 
 
* [[Erosion]]
 
* [[Erosion]]
 
* [[Ice]]
 
* [[Ice]]
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* [[Iceberg]]
 +
* [[Mountain]]
 +
* [[Permafrost]]
 +
* [[Rock (geology)]]
 +
* [[Snow]]
  
 
==References==
 
==References==
 
 
* Benn, Douglas I., and David J. A. Evans. 1998. ''Glaciers & Glaciation.'' London: Arnold. ISBN 0340584319.
 
* 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.
 
* 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 edition. Cambridge: Cambridge University Press. ISBN 978-0521828086.
* 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 edition. Cambridge: Cambridge University Press. ISBN 978-0521836098.
 
 
* 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.
 
* Knight, Peter. 1999. ''Glaciers.'' Cheltenham: Stanley Thornes. ISBN 0748740007.
  
 
==External links==
 
==External links==
 +
All links retrieved June 23, 2017.
 +
 +
*[http://arctic.eas.ualberta.ca/ Arctic and Alpine Research Group.] University of Alberta.
 +
*[http://www.igsoc.org/ International Glaciological Society.]
 +
*[http://www.glaciers-online.net/ Glaciers online.] swisseduc.ch.
 +
*[http://wdcgc.spri.cam.ac.uk/ World Data Centre for Glaciology, Cambridge, UK.]
 +
*[http://www.nsidc.org/ National Snow and Ice Data Center, Boulder, Colorado.]
 +
*[http://www.glims.org/ Global Land Ice Measurements from Space.]
 +
*[http://www.nichols.edu/departments/glacier/ North Cascade Glacier Climate Project.]
  
*[http://www.gi.alaska.edu/snowice/ Snow, Ice, and Permafrost.] Geophysical Institute, University of Alaska Fairbanks. Retrieved August 6, 2008.
 
*[http://arctic.eas.ualberta.ca/ Arctic and Alpine Research Group.] University of Alberta. Retrieved August 6, 2008.
 
*[http://www.igsoc.org/ International Glaciological Society.] Retrieved August 6, 2008.
 
*[http://www.glaciers-online.net/ Glaciers online.] swisseduc.ch. Retrieved August 6, 2008.
 
*[http://wdcgc.spri.cam.ac.uk/ World Data Centre for Glaciology, Cambridge, UK.] Retrieved August 6, 2008.
 
*[http://www.nsidc.org/ National Snow and Ice Data Center, Boulder, Colorado.] Retrieved August 6, 2008.
 
*[http://www.glims.org/ Global Land Ice Measurements from Space.] Retrieved August 6, 2008.
 
*[http://www.nichols.edu/departments/glacier/ North Cascade Glacier Climate Project.] Retrieved August 6, 2008.
 
*[http://www.aber.ac.uk/~glawww/ Centre for Glaciology.] University of Wales, Aberystwyth. Retrieved August 6, 2008.
 
*[http://skua.gps.caltech.edu/ Welcome to the Home of Deep Glaciology.] Caltech. Retrieved August 6, 2008.
 
*[http://www.geophys.washington.edu/Surface/Glaciology/ Glaciology.] University of Washington. Retrieved August 6, 2008.
 
  
 
{{Earth science}}
 
{{Earth science}}
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[[Category:Geology]]
 
[[Category:Geology]]
  
{{credit|210235842}}
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{{credits|Glaciology|210235842|Arête|220081665}}

Latest revision as of 16:03, 23 June 2017

Lateral moraine on a glacier joining the Gorner Glacier in Zermatt, Switzerland. The moraine is the high bank of debris on the left side of the image.

Glaciology is the study of natural forms of ice, particularly glaciers, and phenomena related to ice. It includes the study of how glaciers are formed and depleted, how they move, and how they affect the physical landscape, the climate, and living organisms. It is one of the key areas of polar research. It also involves research into glacial history and the reconstruction of past glaciation, thus providing insights into the ice ages. The apparent presence of ice on Mars and Jupiter's moon Europa brings in an extraterrestrial component to the field.

Thus, glaciology is an interdisciplinary earth science, integrating 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. A person who studies glaciers is called a glaciologist.

Etymology

The word glacier can be traced to the Middle French dialect (Franco-Provençal) term glace, meaning "ice," derived from the Latin term glacies, meaning "frost" or "ice." The word "glaciology" is formed by combining this root with the Greek word λόγος (logos), meaning "speech" or "word."

Types

The process of glaciation is placed in two general categories, described below.

  • Alpine glaciation: It corresponds to accumulations or "rivers of ice" confined to valleys. As ice flows down the slopes of mountainous areas, it forms a "tongue" moving toward the plains below. Alpine glaciers tend to make the topography more rugged.
  • Continental glaciation: It corresponds to unrestricted ice sheets that once covered much of the northern continents but are now found only at high latitudes, such as in Greenland and Antarctica. The sheets are thousands of square kilometers wide and thousands of meters thick. They tend to smooth out the landscape.

Zones of glaciers

  • Accumulation zone: A zone where ice is formed faster than it is removed or lost.
  • Wastage or Ablation zone: A zone where the sum of melting and evaporation (sublimation) of ice is greater than the amount of snow added each year.

Glacial movements and their effects

Striding Edge, an arête viewed from Helvellyn with the corrie Red Tarn to the left and Nethermost Cove to the right.
  • Ablation: In glaciology, ablation means wastage (depletion) of a glacier (or ice or iceberg) through such processes as sublimation, melting, and iceberg calving.
  • Arête: An arête is a thin, almost knife-like, ridge of rock that is typically formed when two glaciers erode adjacent, U-shaped valleys. It may also be formed when two glacial cirques erode headwards toward each other.
  • Bergshrund: A crevasse formed near the head of a glacier, where the moving ice has torn itself apart from stationary ice, in the manner of a geological fault.
  • Cirque (coombe, combe, or corrie): A bowl-shaped depression excavated by the head of a glacier.
  • Creep: The adjustment or deformation of solid material under the influence of stresses.
  • Flow: The movement (of ice) in a constant direction.
  • Fracture: The breaking of ice under stress, especially when movement is too rapid to be accommodated by creep. It happens, for example, as the central part of a glacier moves faster than its edges.
  • Horn: It is a 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 (or quarrying): Plucking is a process by which a glacier erodes chunks of bedrock. When the adhesion of ice to the rock is stronger than the cohesion of the rock, part of the rock leaves with the flowing ice.
  • Tarn: It is a lake formed at the bottom of a cirque when the glacier has melted.
  • Tunnel valley: It is a deep, narrow valley with a U-shaped cross-section, formed by the erosion of rock when the edge of an ice sheet advances up a slope.

Glacial deposits

Stratified

  • Outwash sand/gravel: This is material derived from the front of glaciers, found on a plain.
  • Kettles: A block of stagnant ice leaves a depression or pit.
  • Eskers: These are steep-sided ridges of gravel/sand, possibly caused by streams running under stagnant ice.
  • Kames: The stratified drift builds up low, steep hills.
  • Varves: They are 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: Ranging from glacial flour to boulders, it is deposited by receding/advancing glaciers, forming moraines, and drumlins.
  • Moraines: They include terminal material deposited at the end; ground material deposited as glacier melts; lateral material deposited along the sides.
  • Drumlins: They consist of smooth, elongated hills composed of till.
  • Ribbed moraines: They are large, subglacial elongated hills, transverse to former ice flow.

See also

References
ISBN 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 edition. Cambridge: Cambridge University Press. ISBN 978-0521828086.
  • Hooke, Roger LeB. 2005. Principles of Glacier Mechanics, 2nd edition. Cambridge: Cambridge University Press. ISBN 978-0521836098.
  • Knight, Peter. 1999. Glaciers. Cheltenham: Stanley Thornes. ISBN 0748740007.

External links

All links retrieved June 23, 2017.


General subfields within the earth sciences
Atmospheric sciences | Geodesy | Geology | Geophysics | Glaciology
Hydrology | Oceanography | Soil science


 Physical geography
Land ocean ice cloud 1024.jpg Biogeography · Climatology & paleoclimatology · Coastal/Marine studies · Geodesy · Geomorphology · Glaciology · Hydrology & Hydrography · Landscape ecology · Limnology · Oceanography · Palaeogeography · Pedology · Quaternary Studies

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