Original paper
Reply to Professor Coates
Clayton, K. M.
Zeitschrift für Geomorphologie Volume 10 Issue 4 (1966), p. 475 - 477
3 references
published: Dec 11, 1966
ArtNo. ESP022001004007, Price: 29.00 €
Abstract
I should like to thank Professor Coates for his interest in my paper, and for the very kind way he has put the rather fundamental disagreement that exists between us. He brings to the area a considerably longer acquaintance than I have, while he has been able to introduce evidence that was not readily available when I wrote the paper. All workers in the area will be indebted to him for assembling a great amount of subsurface data that is clearly of importance when we come to interpret the evolution of the landscape. I deal below with his comments in turn, but it will probably be most helpful if I first outline the fundamental difference in our views on the role of ice in this area. Broadly, Coates is impressed by the various meltwater and outwash features that diversity the valleys of the glaciated Allegheny Plateau. Since these proglacial conditions have moved back and forth across the area with each glaciation, their cumulative effect could be considerable. However, my own reading of the field evidence suggests 1) that many of the larger features ascribed by Coates to the action of glacial meltwater are merely touched up by meltwater flow and owe their fundamental form and size to glacial erosion, while 2) I am far from sure that meltwater forms would be enlarged in successive glaciations: in many other areas where these features occur the forms of earlier glacial phases are extinguished by subsequent deposition of till and new channels are cut, often breaking across and so revealing the features of the earlier stage. Similarly, 3) I feel that Coates’ view of what may be admitted as a glacial form is at times rather restrictive, and that his assignation of particular features to fluvial activity rests essentially on a few particular points about their shape, and fails to take into account the convergent evidence for intense glacial erosion. Finallv, 4) the case I have made out for vigorous glacial erosion of this type, particularly along the major valleys, does not exclude nearby areas of the character of ‘backwaters’ where little or no erosion occurs. A peculiar and at times bewildering feature of glacial erosion is its great spatial variation, so that we find little altered preglacial landscapes alongside great troughs and the stubs of former interfluves. D. L. Linton has demonstrated this most convincingly in his account of the landscape of Antarctica.
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