moutonnée

Moutonnée is a French geomorphological term for a glacially sculpted bedrock formation, typically called roche moutonnée in English. It denotes a small to medium-scale elongated knoll produced by the erosive action of a moving glacier.

Morphology and formation: The up-glacier (stoss) face is polished and gently sloping; striations often run parallel to the ice flow. The down-glacier (lee) face is steeper, rougher, and may be chipped by plucking. The overall form aligns roughly with the past direction of glacier movement.

Significance: These features provide evidence of former ice flow and are used in glacial geomorphology to reconstruct paleo-flow directions. They occur on a variety of bedrock types, from hard to moderately resistant rock, and can range from decimetres to tens of metres in length.

Distribution: Common in formerly glaciated regions including mountain belts and shield areas in Europe, North America, and elsewhere. Roche moutonnée are recognizable indicators of the interaction between ice movement and bedrock during past glaciations.

In geology, the term is linked with roche moutonnée and glacial geomorphology, reflecting its role as a classic instrument for interpreting glacier dynamics and landscape evolution.