coireachan

Coireachan are small bowl-shaped hollows found on mountain slopes, a term from Scottish Gaelic. The word coire means “cauldron” or “bowl,” and the suffix -achan marks the diminutive, so coireachan translates roughly as “little corries.” In geology, a cirque is a similar bowl-shaped depression carved by glacial erosion, and coireachan corresponds to this feature in Gaelic terminology.

Formation and characteristics: Coireachan form as valley glaciers erode rock through abrasion and plucking, creating concave floors and steep headwalls. The process concentrates ice and snow, and as the ice retreats, the depressions often remain as basins. Their rims can be sharp or blocky, and many contain a small lake known as a lochan when drainage is restricted. Freeze-thaw weathering and rockfall continue to shape their walls and floors, contributing to talus piles and scree at the margins.

Distribution and usage: The term is most commonly used in Scotland, particularly in the Highlands and other upland regions where Gaelic toponymy preserves traditional names for glacial features. While coireachan are Gaelic-language labels, their geological counterparts—cirques—occur worldwide in alpine and subpolar regions. In maps and field guides, coireachan are often cited as notable landscape features that indicate past glaciation and current hydrological pathways, as meltwater from tarns and lochans can influence local drainage patterns.

Significance: Coireachan illustrate classic glacial landforms adapted to Gaelic-speaking landscapes. They are of interest to geologists, geomorphologists, and hikers, contributing to understanding past ice regimes and present alpine ecology.