Glacier
Topic: Landforms and their Evolution: Rivers, Groundwater, Glaciers, Waves and Wind · NCERT: Class 7, Ch 1 "Geographical Diversity of India"; Class 9, Ch 2 "Shaping of the Earth's Surface"; Class 11, Ch 6 "Landforms and their Evolution"
Meaning
A glacier is a large mass of ice that moves slowly under gravity. It forms where more snow falls each year than melts, so the snow piles up and turns into ice. There are two main kinds:
- Ice sheets spread over land.
- Valley glaciers flow down mountain valleys.
A glacier moves very slowly, from a few centimetres to a few metres a day. Its great weight makes it a powerful agent of erosion, and it can wear away even hard rock that has not been weathered. Over time glaciers can reduce mountains to low hills and plains. Himalayan glaciers feed major Indian rivers, so they matter for water security.
Example
The Gangotri glacier in Uttarakhand is a valley glacier. The Bhagirathi river rises at Gaumukh, the snout (front end) of this glacier.
Related concepts
- Valley glacier
- Continental glacier
- Plucking
- Cirque
- Tarn
- Horn
- Arete
- U-shaped valley
- Hanging valley
- Truncated spur