Erosional landforms of glacier Upsc

Cirque

Cirque
Cirque By JJ Harrison (https://www.jjharrison.com.au/) – Own work, GFDL 1.2, https://commons.wikimedia.org/w/index.php?curid=6760381

Cirques are the most common landforms in glaciated mountains. The cirques quite often are found at the heads of glacial valleys.

The accumulated ice cuts these cirques while moving down the mountain tops. They are deep, long, and wide troughs or basins with very steep concave to vertically dropping high walls at its head as well as sides.

A lake of water can be seen quite often within the cirques after the glacier disappears. Such lakes are called cirque or tarn lakes. There can be two or more cirques one leading into another down below in a stepped sequence.

Horns and Serrated Ridges

Horns form through headward erosion of the cirque walls. If three or more radiating glaciers cut headward until their cirques meet, high, sharp-pointed, and steep-sided peaks called horns form.

Horns
Horns Geology By US Geological Survey – http://libraryphoto.cr.usgs.gov/cgi-bin/show_picture.cgi?ID=ID.%20Carrara,%20P.%20348ct, Public Domain, https://commons.wikimedia.org/w/index.php?curid=22025810

The divides between the cirque side walls or headwalls get narrow because of progressive erosion and turn into serrated or saw-toothed ridges sometimes referred to as arĂȘtes with very sharp crest and a zig-zag outline.

The highest peak in the Alps, Matterhorn and the highest peak in the Himalayas, Everest are in fact horns formed through headward erosion of radiating cirques.

Serrated Ridges By Alpsdake – Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=11567654

Glacial Valleys/Troughs

Glacial Valleys/Troughs
Glacial Valleys/Troughs By DanHobley – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=19290010

Glaciated valleys are trough-like and U-shaped with broad floors and relatively smooth, and steep sides. The valleys may contain littered debris or debris shaped as moraines with a swampy appearance. There may be lakes gouged out of the rocky floor or formed by debris within the valleys.

There can be hanging valleys at an elevation on one or both sides of the main glacial valley. The faces of divides or spurs of such hanging valleys opening into main glacial valleys are quite often truncated to give them an appearance like triangular facets.

Very deep glacial troughs filled with seawater and making up shorelines (in high latitudes) are called fjords/fiords.

depositional landforms of glacier

* * All the Notes in this blog, are referred from Tamil Nadu State Board Books and Samacheer Kalvi Books. Kindly check with the original Tamil Nadu state board books and Ncert Books.