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Geography

Surge-type Glaciers

  • 08 May 2020
  • 4 min read

Why in News

Scientists from the Wadia Institute of Himalayan Geology (WIHG), Dehradun have found a seasonal advancement in 220 surging or surge-type glaciers in the Karakoram Range of Ladakh.

  • WIHG is an autonomous institute under the Department of Science and Technology (DST).

Key Points

  • Surging or Surge-type glaciers are a certain type of glaciers that have shown advancement in volume and length over a period of time.
    • Such glaciers go against the normal trend of considerable reduction in volume and length of most glaciers in the Himalaya in recent decades.
  • Surging glaciers represent 40% of the total glaciated area of the Karakoram range.
  • Surging glaciers do not flow at a constant speed, rather are subjected to cyclical flow instabilities.
  • The oscillation of such glaciers have been broadly classified into two phases:
    • Active (Surge) Phase- brief (months to years) rapid flow.
    • Quiescent Phase- lengthy (tens to hundreds of years) slow flow or stagnation.
  • It was inferred that surge during winter is more controlled because there is low amount of meltwater which flows unsteadily underneath the glaciers.
  • The surging stops in summer because of the channelised flow of the melted water.

Significance of Studying Surging Glaciers

  • Surging glaciers can lead to the destruction of villages, roads and bridges.
  • They can also advance across a river valley and form an ice-dammed lake. These lakes can form catastrophic outburst floods.
  • Therefore, monitoring of glacier surges, ice-dammed lake formation and drainage is of paramount importance.

Glaciers

  • Masses of ice moving as sheets over the land (continental glacier or piedmont glacier if a vast sheet of ice is spread over the plains at the foot of mountains) or as linear flows down the slopes of mountains in broad trough-like valleys (mountain and valley glaciers) are called glaciers.
  • The movement of glaciers is slow unlike water flow ranging from a few centimetres to a few meters per day. Glaciers move basically because of the force of gravity.
  • Erosion by glaciers is tremendous because of friction caused by sheer weight of the ice.
    • The material plucked from the land by glaciers (usually large-sized angular blocks and fragments) get dragged along the floors or sides of the valleys and cause great damage through abrasion and plucking.
    • Glaciers can cause significant damage to even un-weathered rocks and can reduce high mountains into low hills and plains.
  • As glaciers continue to move, debris gets removed, divides get lowered and eventually the slope is reduced to such an extent that glaciers stop moving, leaving only a mass of low hills and vast outwash plains along with other depositional features.
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