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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. [ 1 ] 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 ...
The resulting erosional landforms include striations, cirques, glacial horns, arêtes, trim lines, U-shaped valleys, roches moutonnées, overdeepenings and hanging valleys. Striations: grooves and indentations in rock outcrops, formed by the scraping of small sediments on the bottom of a glacier across the Earth's surface. The direction of ...
Lower Curtis Glacier is a cirque glacier in the North Cascades in the U.S. state of Washington. Cirque glaciers are glaciers that appear in bowl-shaped valley hollows. [4] [12] Snow easily settles in the topographic structure; it is turned to ice as more snow falls and is subsequently compressed. [12]
By contrast with glacial U-shaped valleys, there is less downward and sideways erosion. The severe downslope denudation results in gently sloping valley sides; their transition to the actual valley bottom is unclear. Trough-shaped valleys occur mainly in periglacial regions and in tropical regions of variable wetness. Both climates are ...
Glacial erosion often causes U-shaped valleys to form. [6] These valleys allow for directed water movement such as seen in glacial streams with meltwater. [6] Subglacial fluvial erosion and glacial outwash occurs from the melting of the glacier and creates water flow that can wear bedrock. [4]
During glaciation, these valleys are often widened, deepened and smoothed to form a U-shaped glacial valley or glacial trough, as it is sometimes called. [68] The erosion that creates glacial valleys truncates any spurs of rock or earth that may have earlier extended across the valley, creating broadly triangular-shaped cliffs called truncated ...
The gradual movement of ice down a valley causes abrasion and plucking of the underlying rock. Abrasion produces fine sediment, termed glacial flour. The debris transported by the glacier, when the glacier recedes, is termed a moraine. Glacial erosion is responsible for U-shaped valleys, as opposed to the V-shaped valleys of fluvial origin. [56]
The moraine was formed during the Crown Point Phase of the Wisconsin glaciation. At this time the glacier covering the area had grown thin, so it was restrained by dolomite rock layers in the Lake Michigan basin. Where the glacier stopped, glacial till and sand was deposited, creating the hills of the moraine.