Roche Moutonnee Formation

Roche moutonnee formation is the process by which an overriding glacier shapes an outcrop of resistant bedrock into an asymmetric mound: the up-glacier side is smoothed and gently sloped by abrasion as ice and embedded debris scrape across it, while the down-glacier side is left steep and jagged where glacial plucking pulls blocks of rock away along joints and fractures loosened by pressure release. The resulting asymmetry lets a geologist read the direction of past ice flow directly off the landform long after the glacier is gone.