U-shaped valley

A glaciated valley in the Altai Mountains of Russia showing the characteristic U shape. Malyovitsa U-shaped valley, Rila Mountain, Bulgaria U-shaped valley in Leh valley, Ladakh, NW Indian Himalaya. The glacier visible at the head of the valley is the last remnant of the formerly much more extensive glacier which carved it. U-shaped valley with lake in Myklebustdalen, Nordfjord, Sogn og Fjordane, Norway.

U-shaped valleys, also called trough valleys or glacial troughs, are formed by the process of glaciation. They are characteristic of mountain glaciation in particular. They have a characteristic U shape in cross-section, with steep, straight sides and a flat or rounded bottom (by contrast, valleys carved by rivers tend to be V-shaped in cross-section). Glaciated valleys are formed when a glacier travels across and down a slope, carving the valley by the action of scouring. When the ice recedes or thaws, the valley remains, often littered with small boulders that were transported within the ice, called glacial till or glacial erratic.