Circus glacier

Lower Curtis Circle Glacier, North Cascades, Washington State, United States of America.

Martial Glacier, Tierra del Fuego, Argentina.

Laguna Grande de Peñalara, en el Circo glaciar de Peñalara (Sierra de Guadarrama, Spain). It is the residual lagoon of a glacier that at its last stage of regression was a circus glacier.

A cirque glacier is a type of glacier that is confined to its basin or cirque of accumulation. It barely has a glacier tongue and has a reduced ablation zone due to the low abundance of ice.

Cirque Glacier is a mountain glacier. It usually has a gently sloping bottom, and may be the result of glacial retreat in which the glacier tongue has disappeared. It may also be, in a growth phase, the stage before the appearance of the glacier tongue, when accumulation of ice still does not allow the glacier to overflow from its cirque.

It is sometimes difficult to distinguish a cirque glacier from a suspended glacier, because their morphology is very similar. In the suspended glacier, the abrupt topography prevents the growth of the glacier outside its cirque of accumulation and the excess ice is removed by falling seracs.

Cirque glacier is not to be confused with a glacial cirque which is a part of a glacier. The glacial cirque is the circular or semicircular basin produced by the action of ice from a glacier in its accumulation or feeding zone. The compressed ice mass moves by sliding and this action forms, by abrasion, the circular rocky concavity or circus. In the case of a valley glacier, the glacial cirque is located at its head, the starting point of the glacial river. Cirques can be saddle-shaped or amphitheater-shaped, and have steep or nearly vertical flanks surrounded by ridges.

The circus is usually divided into two parts: the lower part, where snow and ice accumulate, and the upper part, with steeper slopes but more compact ice due to its lower temperature. Both areas are usually separated by a more or less transverse or horizontal crack called rimaya.

Circus Glaciers

Spain

• Laguna Grande de Peñalara, Sierra de Guadarrama

Argentina

• Martial Glacier, Tierra del Fuego

United States

• Teton Glacier, Grand Teton National Park, Wyoming
• Lower Curtis Glacier, North Cascades, Washington State

France

• Gabietos Glacier, Macizo de Monte Perdido-Gavarnie, Pyrenees
• Taillon Glacier, Macizo de Monte Perdido-Gavarnie, Pyrenees
• Glacier of Arsine, Alpes

Italy

• Frébouze Glacier