Erosional Landforms

Cirque:

    • Cirques are horseshoe shaped, deep, long and wide troughs or basins with very steep to vertically dropping high walls at its head as well as sides.
    • Cirques are often found along the head of Glacial Valley
    • The accumulated ice cuts these cirques while moving down the mountain tops.
    • After the glacier melts, water fills these cirques, and they are known as cirque lake.

 

Glacial Trough:

Is an original stream-cut valley, further modified by glacial action. Step- formation takes place at maturity; otherwise it is an ungraded and irregular feature.

 

Horns:

    • Horns form through head-ward 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.

 

Aretes:

    • Arete is a narrow ridge of rock which separates two valleys.
    • Aretes are typically formed when two glacial cirques erode head-wards towards one another
    • The divides between Cirque side walls or head walls get narrow because of progressive erosion and turn into serrated or saw-toothed ridges referred to as aretes with very sharp crest and a zig-zag outline.

 

Glacial Valleys:

    • Glaciated valleys are trough-like and U-shaped with wide, flat floors and relatively smooth, and steep sides.
    • When the glacier disappears, and water fills the deep narrow sections of the valley, a ribbon lake is formed.

 

Fjords/Fiords:

    • A fjord or fiord is a long, narrow and steep-sided inlet created by a glacier
    • They are formed where the lower end of a very deep glacial trough is filled with sea water
    • Fjords are common in Norway, Chile, and New Zealand etc.

 

erosional landforms by glaciers

Hanging Valleys:

    • A hanging valley is a tributary valley that is higher than the main valley. Hanging valleys are common along glaciated fjords and U-shaped valleys.
    • The main valley is eroded much more rapidly than the tributary valleys as it contains a much larger glacier
    • After the ice has melted tributary valley, therefore, hangs above the main 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.
    • Often, waterfalls form at or near the outlet of the upper valley
    • Thus, the hanging valley may form a natural head of water for generating hydroelectric power

erosional landforms by ice