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If the glacial action erodes through, a spillway (or col) forms; Horn: a sharp peak connecting multiple glacier intersections, made up of multiple arêtes. Valley step: an abrupt change in the longitudinal slope of a glacial valley; Hanging Valleys: Formed by glacial meltwater eroding the land partially, often accompanied by a waterfall. [2]
The movement of these continental glaciers created many now-familiar glacial landforms. As the glaciers were expanded, due to their accumulating weight of snow and ice, they crushed and redistributed surface rocks, creating erosional landforms such as striations , cirques , and hanging valleys .
Glacial polishing is the result of clasts embedded in glacial ice passing over bedrock and grinding down the top of the rock into a smoother surface. The small rocks entrained by plucking act like sandpaper to the downhill slope. [7] This creates an almost mirror like surface in the rock.
There is a glacier-fed lake in addition to the formation of a small channel heading in the southeast direction. During glacial retreat, meltwater flows in the opposite direction of the retreat, causing braided streams and channels to form. A terminal moraine creates a barrier helping to trap water in a newly-formed glacial lake.
Roche moutonnée near Myot Hill, Scotland In glaciology, a roche moutonnée (or sheepback) is a rock formation created by the passing of a glacier.The passage of glacial ice over underlying bedrock often results in asymmetric erosional forms as a result of abrasion on the "stoss" (upstream) side of the rock, and plucking (i.e. pieces cracked off) on the "lee" (downstream) side.
The sediment nearer the glacier typically is coarser than non-glacial sediment, ranging from boulders down to sand, but with little silt and clay since the water usually flows too fast to allow these fine particle to settle until it is a considerable distance from the glacier. [20]
Factors that can slow or stop basal sliding relate to the glacier's composition and also the surrounding environment. Glacier movement is resisted by debris, whether it is inside the glacier or under the glacier. This can affect the amount of movement that is made by the glacier by a large percentage especially if the slope on which it lies is low.
Glacial erosion proceeds by abrasion as ice and entrained debris moves across the underlying bedrock, by water induced erosion and transport of sediment, and by freeze-thaw cycles which weather the bedrock. All processes are most effective at the bottom of glacial ice – hence the glacier erodes at the bottom.