Glacial valley, also called glacial trough, stream valley that has been glaciated, usually to a typical catenary, or U-shaped, cross section. U-shaped valleys occur in many parts of the world and are characteristic features of mountain glaciation. These glacial troughs may be several thousand feet deep and tens of miles long.
When allowed to spread out, a glacier erodes the landscape uniformly, but when confined within valley walls it tends to deepen and widen the valley floor. The commonly V-shaped stream valley is converted to a U-shaped valley because the U-shape provides the least frictional resistance to the moving glacier. (The Encyclopædia Britannica)
I took the picture below when I was in a gravity and magnetic excursion with my colleagues and students from other countries, sweden, Norway, Italy, Germany, Cameron, Iran. Finsetlia Eikesdalen is well-known place for its wonderful scenery and rock scarps. See the map: http://bit.ly/1mJHicf
