Glacial processes and their land forms.
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Glaciers are masses of ice that move due to gravity. They erode the landscape through abrasion and plucking, and transport material large distances. Glaciers deposit this material as till or outwash. Glacial processes form characteristic landforms such as cirques, arêtes, and u-shaped valleys through erosion and landforms like moraines and eskers through deposition. Glacial lakes are also left behind when a glacier melts.
Glacial processes and their land forms.
- 1. Glacial Processes and theirGlacial Processes and their LandformsLandforms A SeminarOn
- 3. Glaciers:Glaciers: Glaciers are masses of ice and firn formed by the recrystallization of snow and meltwater which lies entirely or largely on land and gives evidence of either present or former movement.
- 4. Ahlmann’s Morphological Classification of GlaciersAhlmann’s Morphological Classification of Glaciers Type A: 1. Continental Glaciers 2. Glacier Caps 3. Highland Glaciers Type B: 4. Valley Glaciers 5. Transection Glaciers 6. Cirque Glaciers 7. Glacier Tongues Type C: 8. Piedmont Glaciers 9. Foot Glaciers 10. Shelf Ice
- 10. Shelf Ice
- 11. Glacial Processes:Glacial Processes: Glacial movement occurs when the growing ice mass becomes too heavy to maintain its rigid shape and begins to flow by plastic deformation. Flow of Glaciers:Flow of Glaciers:
- 12. Velocity of Glaciers:Velocity of Glaciers: The velocity of flow of glacier ice is influenced by a variety of factors such as the gradient of the valley floor, the temperature and thickness of the ice, and the constriction caused by the valley walls. The movement of ice over the ground in most temperate glaciers is enhanced by a process known as basal sliding ..
- 13. Glacial Erosion:Glacial Erosion: Abrasion Scouring by rock fragments embedded in the sliding ice. It produces rock flour, fine sediment that becomes suspended in glacial lakes. Plucking (quarrying) As the glacier flows over the bedrock's fractured surface, it softens and lifts blocks of rock that are brought into the ice. Glacial erosion, transport and Deposition:Glacial erosion, transport and Deposition:
- 14. Glacial Transportation:Glacial Transportation: Glaciers are capable of transporting very large volumes of material over very large distances.. The material carried by a glacier can be classified as: o Supraglacial- this is material carried on top of the ice. o Englacial - this is material carried within the glacier itself o Subglacial - this is material carried along in the base of the glacier.
- 15. Glacial Deposition:Glacial Deposition: Deposition of material carried by the glacier occurs either as partial deposition as a result of a reduction in the velocity of the glacier or complete deposition as the glacier retreats and melts. Glacial sediment is collectively known as drift. Material that is deposited directly by ice is known as till whereas material deposited by glacial meltwater, are known as outwash deposits..
- 16. Glacial Tills: Lodgement till is where material beneath the glacier has become lodged in the bed. When a glacier is so overloaded with debris it smears it onto the valley floor. An increase in ice thickness can also increase friction beneath the ice, causing lodgement. Ablation till is where material is deposited as the ice around it melts away. This may because of solar radiation causing melting along the margins of glaciers, or it may even be due to the melting of basal ice due to geothermal heating.
- 17. Glacial Landforms:Glacial Landforms: Erosional Landforms:Erosional Landforms: o Striations o Cirques o Glacial Horns o Ar tesê o Trim Lines o U-shaped Valleys o Roches Moutonn esé o Overdeepenings o Hanging Valleys.
- 18. o Moraines o Eskers o Kames o Drumlins o Erratics Depositional Landforms:Depositional Landforms:
- 19. Lakes and ponds may also be caused by glacial movement. o Moraine-dammed lakes: Occurs when a stream (or snow runoff) is dammed by glacial debris. o Kettle lake: Depression, formed by a block of ice separated from the main glacier, in which the lake forms. o Glacial Lake: A lake that formed between the front of a glacier and the last terminal moraine. Glacial Lakes and Ponds:Glacial Lakes and Ponds:
- 21. Glacial Horns Ar tesê
- 22. Trim Lines U-shaped Valleys
- 23. Roches Moutonn esé Overdeepenings FjordFjord Fjord Lake Fjord Lake
- 24. Hanging Valleys.
- 25. Moraines Eskers
- 26. Kames Drumlins
- 27. Erratics
- 28. Moraine-dammed lakes Kettle lakes
- 29. Glacial Lakes
- 30. Glaciers are rivers of ice in a continuous movement. Glacial motion occurs when the gradient of the valley floor is sufficient for the glacier to overcome friction. Glacial erosion takes place by abrasion and plucking Glaciers can carry huge amount of materials to vast distances. Conclusion:Conclusion:
- 31. Glacial deposition can be in the form of Lodgement Tills, Ablation Tills and Outwash Deposits. Glacial processes gives rise to erosional landforms, depositional landforms and lakes.
- 32. References:References: Raina, V. K. (2006). Glaciers: The Rivers of Ice, Popular Science Series No. 2, Geological Society of India, 6 pp. Thornbury, W. D. (2004). Principles of Geomorphology, CBS Publishers & Distributors Pvt. Ltd., pp. 346-382. Websites: http://cgz.e2bn.net/e2bn/leas/c99/schools/cgz/accounts/st aff/rchambers/GeoBytes/AS %20A2/A2/Glaciation.Web/glacial_deposition.htm http://uregina.ca/~sauchyn/geog323/glacial2.html http://en.wikipedia.org/wiki/Glacial_landform