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GeogOnline: GG4 - Glacial Erosion Landforms 2
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		This photograph shows an example of a U-shaped glacial valley or a glacial trough. The Jollie River Valley in New Zealand.The valley is relatively straight, which is common for most glacial valleys, and the valley bottom is flat with steeply sloping sides. These clues indicate that a glacier carved the valley, not the river currently located here. The valley was probably a river valley before the Ice age and was modify by the glacier deepening the valley by abrasion processes. The glacier followed the river valley as the easiest rout downslope from its circque. The present day river is a misfit and is modifying the landforms produced by the glaciation.
This diagram shows the smaller scale contributory landforms tat can be found within a glaciated valley like Tal-y-Llyn valley below Cader Idris. Notice the post glacial modification by the misfit stream and the alluvial fan built by material deposited at the foot of the waterfall.
		The glacier occupies a pre-existing river valley and erodes away its interlocking spurs by abrasion processes. It aslo deepens the valley floor considerably. However, here you can see exposed sides above the level of the glacier which are not being eroded. These are left as gentler slopes called alps or benches when the ice melts. The lie above he steeper blunted truncated spurs.
The alps or benches are often used as farm or ski slopes in the alps but at the some point downhill the gradient suddenly becomes almost vertical when the top of the truncated spur is reached.
		This photo shows a tremendous view of almost vertical truncated spurs at the sides of a glaciated valley. This is the Yosemite Valley of California I think.
This hanging valley is located along Milford Sound on the South Island of New Zealand. The water in the foreground is part of Milford Sound, a huge U-shaped valley now flooded with sea water. Glacial troughs that fill with sea water are called fjords. The waterfall comes out of another U-shaped valley where a smaller glacier existed. Because this glacier was smaller than the one that filled Milford Sound, its valley bottom is at a higher elevation than the bottom of Milford Sound, and as a result, today we see a hanging valley.
		This is Wast Water glaciated valley floor lake in the English Lake District. In some places perhaps where the geology of the valley floor is made of weaker rock the glacier overdeepens its valley. when the ice melt this overdeepened section has poor drainage and fills up as a ribbon or finger glaciated valley floor lake.
The map shows Wast Water valley with the lake and the steep truncated spur valley sides. Freeze thaw weathering has produced a lot of scree or talus lower slope material which is also named on the map and visible as grey on the photo. Can you also spot a tarn? The English Lake District is a managed former glacial environment which has National Park status.
		Trough Ends Many glacial troughs end in an abrupt wall known as a trough end. The over deepening of the valley at this point is likely the result of a glacier’s increased erosive power. This would occur where a number of corrie glaciers coalesced. The photo shows a view from Kirkstone Pass at the end of Ullswater looking down from the tough end into the main glaciated valley.