Cirque

Circosabisko

Thornton Lakes 25929

Glacial Tarn Formation EN

Marichin cirkus IMG 1452

Lowercurtis

Cirque is a term that originates from the French language, meaning 'circle' or 'ring'. In the context of physical geography, a cirque (also known as a corrie or cwm) is a type of landform linked to glacial activity. It is a steep-walled, amphitheater-shaped basin carved by the action of glaciers and often found on the side of mountains. Cirques are significant in the study of glaciology, a branch of geography that focuses on glaciers and their effects on the landscape.

Formation

Cirques are formed through the process of glaciation, which involves the accumulation, compaction, and recrystallization of snow into ice. This process occurs over many years, often in pre-existing depressions on the sides of mountains. As the glacier moves, it erodes the landscape through a combination of plucking and abrasion, deepening and widening the depression into a bowl-like shape. The back wall of a cirque is typically steep and may be a cliff, while the floor is often flat and can contain a small lake known as a tarn after the glacier melts.

Characteristics

Cirques exhibit several distinctive characteristics:

• Steep sides and a wide opening at the down-valley end, shaped somewhat like an amphitheater.
• A lip at the lower edge, which is often raised due to the slower erosion rate there compared to the back wall.
• A flat or gently sloping floor, which is the result of sedimentation and the melting of the glacier that once filled the cirque.

Location and Examples

Cirques can be found in mountain ranges across the world, including the Rocky Mountains, the Himalayas, the Alps, and the Andes. Notable examples include the Tuckerman Ravine on Mount Washington in the United States and the Cirque de Gavarnie in the Pyrenees of France.

Ecological and Climatic Significance

Cirques are of interest not only to geologists and geographers but also to ecologists and climatologists. They can serve as isolated habitats for unique flora and fauna, offering insights into species adaptation and biodiversity. Additionally, the study of cirques and their formation provides valuable information on past climatic conditions, contributing to our understanding of climate change and its impact on glacial activity.

Tourism and Recreation

Many cirques are popular destinations for tourists and outdoor enthusiasts. Their dramatic landscapes offer opportunities for hiking, skiing, and mountaineering. The natural beauty and challenge of these formations attract visitors from around the world, contributing to the local economies of mountain regions.