Title Bar: Illustrated Glossary of Alpine Glacial 
	  Landforms | Home   | Glossary   | Exercise |


    Erosional Landforms
    Giant stair steps
    Glacial trough
    Hanging valley
    Paternoster lakes
    U-shaped valley

    Depositional Landforms
    End moraine
    Ground moraine
    Lateral moraine
    Medial moraine

    Ice Features
    Cirque glacier
    Valley glacier
    Ice fall

A glacially eroded valley. In mountainous regions rivers tend to carve out valleys with narrow bottoms, or V-shaped valleys. When alpine glaciers flow through these pre-existing valleys, the glaciers reshape the valley and widen the valley bottom. The result is a valley shaped like a parabola or a trough or a capital letter U (U-shaped valley).

Photo: glacial trough/u-shaped valley

Photo: R. Schukar. Used with permission.

Topographic Map: U-shaped valley/glacial trough
The photo shows the glacial trough (or U-shaped valley) currently occupied by the Saint Mary River in Glacier National Park. Although no one may have seen the glacier when it filled this valley, you can tell that the valley was shaped by a glacier and not by the Saint Mary River simply based on the shape of the valley. In the photo, you are looking toward the northeast. On the map, north is toward the top. The wide spacing of the contour lines on the map reveals the relatively flat floor of the valley while the more closely spaced contour lines along the sides of the valley show the steeper valley walls.
| More Examples of Glacial Troughs/U-Shaped Valleys |

| Home | Glossary | Exercise |

| Virtual Geography Department Project | Physical Geography Working Group |
All commercial rights reserved. Copyright 2010 by Karen A. Lemke. Earlier copyright 2002 by Karen A. Lemke, and 1998 by Karen A. Lemke and Linda Freeman.
Last updated June 2010 KAL.