Pelly Mountains, Yukon

This photograph, taken near the Pelly Mountains in the southeastern Yukon, shows a valley whose very pronounced U-shape indicates that it has been modified by a glacier. A glacier’s base has many embedded rock fragments that erode the surfaces beneath them, changing the landscape significantly.

Source: Geological Survey of Canada, photograph number 2002-611. Reproduced with the permission of the Minister of Public Works and Government Services Canada, 2005 and courtesy of Natural Resources Canada, Geological Survey of Canada.