Tarn
Also called: Cirque lake · Topic: Landforms and their Evolution: Rivers, Groundwater, Glaciers, Waves and Wind · NCERT: Class 11, Ch 6 "Landforms and their Evolution"
Meaning
A tarn, or cirque lake, is a small, deep lake in the rock hollow of a cirque (an armchair-shaped basin cut by ice). It forms after the glacier melts away. The cirque floor is often scooped out deeper than its outer edge, so water collects there. Sometimes several cirques lie one above another like steps, and each holds its own tarn.
Example
Red Tarn lies in a cirque below the mountain Helvellyn in the Lake District, England.
Don't confuse with
- Moraine-dammed lake: water held back behind a ridge of glacial debris, not in a rock basin. A sudden breach of such a lake can cause a GLOF (glacial lake outburst flood), as at South Lhonak, Sikkim, in October 2023.
- Oxbow lake: a curved lake left by a river meander. It has nothing to do with ice.
Related concepts
- Glacier
- Valley glacier
- Continental glacier
- Plucking
- Cirque
- Horn
- Arete
- U-shaped valley
- Hanging valley
- Truncated spur