THE GLACIAL GEOMORPHOLOGY OF THE AREA AROUND HYDE, CHESHIRE

Abstract

Summary During the main Weichsel glacial period ice movement around Hyde became impeded by the local Pennine relief to such an extent that lobes of ice were ultimately detached from the main body of the ice sheet and left to stagnate in the valleys of the Mersey headwater streams. Large volumes of meltwater were released in the areas adjoining the hills and the streams flowing at the ice margins constructed a number of fluvio-glacial depositional landforms and filled with sediment the valleys eroded by pre-glacial streams. Local relief exerted a strong influence upon meltwater flow and ice movements and in consequence the mode of sedimentation, the stratigraphy and lithological character of the glacial deposits are frequently a reflection of local environmental conditions. In this area therefore it has not been possible to recognize a simple stratigraphical succession applicable to the whole area and therefore the glacial deposits are described with reference to their morphology and topographical expression. Former ice sheet incursions created a number of modifications in the local drainage network. Most diversions resulted from events that occurred during the Weichsel Glaciation but the analysis of the bedrock topography indicates that some alterations of the drainage pattern occurred earlier in the Pleistocene Epoch. The erosion of several now abandoned channels and of the “post-glacial” gorges is attributed to the work of sub-glacial meltwaters which also deposited some varved deposits on the valley floors. Beyond the former ice margin there is considerable evidence of prolonged periglacial denudation and it is concluded that the glacial incursion was only of short duration and was the climax to a long period of cold, but not glacial, climate which persisted from about 75,000 to 25,000 years B.P.