Truncated spur
Also called: Triangular facet · Topic: Landforms and their Evolution: Rivers, Groundwater, Glaciers, Waves and Wind · NCERT: Class 11, Ch 6 "Landforms and their Evolution"
Meaning
A truncated spur is the steep, triangular face left when a glacier cuts off the end of a spur. A spur is a ridge of land that sticks out into a valley from its side. A river winds around spurs in its valley. A glacier is too thick and rigid to bend around them, so it moves straight down the valley and grinds their ends away. This leaves the steep triangular faces along the walls of a straight U-shaped trough. Hanging valleys often open between these cut-off spurs.
Example
The Lauterbrunnen valley in the Swiss Alps has steep walls shaped by cut-off spurs. Waterfalls from hanging side valleys pour over them.
Don't confuse with
- Interlocking spurs: ridges that fit into each other like a zip in a winding V-shaped river valley. A glacier cuts off these spurs and turns them into truncated spurs.
Related concepts
- Glacier
- Valley glacier
- Continental glacier
- Plucking
- Cirque
- Tarn
- Horn
- Arete
- U-shaped valley
- Hanging valley