Longitudinal Profiles of Some Glacial Overflow Channels

Peel found in Northumberland that each of the two profiles examined in detail are of a or up-and-down form. The northern and southern slopes of the Beldon Cleugh channel are of almost equal length; peat fills a large depression at the crest of the hump, and various minor concavities occur on the northern slope. By contrast, the East Dipton channel E ^^ W possesses no complications in the way of peat accumulations but the eastern slope is much longer than the western. In north Lincolnshire the pre? sent writer has noted several glacial overflow channels with a humped profile. Only in a few places do sands and gravels mark the solid chalk in which the channels are eroded, and even here the debris is firmly con? sidered to be essentially contemporaneous with the channelcutting period. In no instance does such debris affect the general morphology of the spillways, and in particular it does not intrinsically contribute to the development of the humped longitudinal profile which is formed of a chalk surface and is thus a purely erosional feature. The channels are considered to have formed during the retreat of the ice with which the Hessle boulder-clay is associated (i.e. they are related to the most recent glaciation) and have been resolved into several series correlated with various positions of the ice front. The waters which excavated the channels flowed northward to the Kirmington valley and at least two earlier, higher level, stages overflowed westward through the Barnetby Gap, which breaches the Wold chalk escarpment, and into an extension of Lake Humber which occupied the Ancholme valley.3 Of the channels, few were found to be suitable for levelling and various factors narrowed the possible choices to four: these were surveyed with a Dumpy level, with the results shown in Figure i. Rarendale Valley Vertical exaggeration X 30

Geography · Geomorphology · Glacial period · Physical geography · Geology · Hydrology and Watershed Management Studies · Landslides and related hazards · Soil erosion and sediment transport

• Structurally-controlled fluvioglacial erosion features near Schefferville, Québec

  Werner Barr, William Barr•Cahiers de géographie du Québec•2005

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