Perhaps the most typical of landforms which can claim to have been largely fashioned by ice is the Unshaped valley or glacial trough.Things to do in the lake district With its straight sides and iceshorn crags dropping steeply to the valley bottom, the form is familiar enough not to require much elaboration. Favourite valleys like Great Langdale, Borrowdale and Troutbeck all possess these basic features and have a common enclosed appearance, especially towards their heads where the fell slopes crowd in on every side. Each valley, however, has its own distinctive feature imparting a variety which is part of the charm of the Lake District landscape. Few greater contrasts exist than, say, between the rich greenery of Long Sleddale and the gaunt grey and often screecovered slopes which surround Wastwater.
Again, the twisting form of Great Langdale is very different from Borrowdale, where straight contours are broken by the great rock constriction known as the Jaws.Variety within a single valley is also a feature of the area, as is apparent in traversing the upper section of the River Cocker. Starting as Gatesgarthdale Beck at the head of Hollister Pass, the youthful stream winds its way over boulder beds and around great rocky buttresses within a short distance of its source. The valley here has a typical V shaped cross profile, for extensive scree clothing the lower slopes has modified the original U section of the glaciated valley. At Gatesgarth the valley opens out and the beck now flows with greater serenity across flats which were once covered by the waters of an extended Lake Buttermere. At the present lake edge the river is gradually building out a promontory with debris brought down when it is in spate.
From the head of Buttermere downstream for about five miles, the valley is more open although much of its flow is taken up with the lakes of Buttermere and Crummock Water. At Hause Point the rocky buttress comes right down to the edge of the lake and the valley is more constricted. Lower down it opens out again although the rocky end of Grasmoor and the crags of Mellbreak must have resisted any glacier as it moved down the valley, and were partly shorn away in the process. At the lower end of Crummock Water the valley bifurcates and the River Cocker chooses the eastern branch as it pursues its relentless course to join the Derwent at Cockermouth.
The valley now is wide and open, forming the pleasant Vale of Lorton so loved by Wordsworth for its unspoilt beauty. In this lower section the former valley glacier'began to dump some of the debris it had gathered by its erosion farther upstream. Near Armaside there is a small moraine, now capped with trees, marking a point where the glacier tem¬porarily halted and began to melt. Although a mere ten miles from the head of the Homster Pass, the rich green acres of the Vale of Lorton represent the very antithesis to the bare boulder slopes of the source region.
No comments:
Post a Comment