glacial trough
a large u-shaped valley formed from a v-shaped valley by glacial erosion.
Image

Western Brook glacial trough, Newfoundland, Canada. The sheer walls of this glacial trough soar up to 700 m high, and the glacial basin is 500 m deep in places.
Natural Resources Canada, copyright Terrain Sciences Division, Geological Survey of Canada
Topic(s):
glaciers