Roche Moutonnee on Cadair Idris, Wales

February 09, 2013

RocheMoun33 (2)

Photographer: Mike J. Smith; Mike's Web site
Summary Author: Mike J. Smith

The snowy photo above, taken on the Welsh mountain Cadair Idris, shows a roche moutonnee, an erosional landform created where ice, during previous glacial periods, flowed over hard, difficult-to-erode bedrock. The bedrock isn't completely removed by the glacial ice, but it takes on an asymmetric streamlined shape, with heavy abrasion occurring on the upstream end (left) and plucking on the downstream end (right) of the flowing ice. Abrasion tends to result in smooth surfaces, while plucking rips large chunks away from the bedrock. The upstream abrasions result in scratches across the faces of the rocks (striations). Photo taken on January 12, 1992.

Photo details: Camera Maker: Pentax Model P30 camera; Adobe Lightroom 4.2. software.