Morphology and Anatomy of the Norwood Esker, Ontario

Publication Year:
1978
Usage 685
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Repository URL:
http://scholars.wlu.ca/etd/1504; http://scholars.wlu.ca/cgi/viewcontent.cgi?article=2587&context=etd
Author(s):
Dixon, John Arthur
Tags:
Geomorphology; Physical and Environmental Geography
thesis / dissertation description
Over its 25 km. length the Norwood esker traverses two morphologically different areas, a northern section of kame, and a southern section of elongated drumlins. In the north the esker consists of single and multiple ridges: where multiple, the ridges are superimposed on a lower, broader, plateau-like base. In the south a high, steep-sided single ridge is present. In both areas, where single, the ridge splits locally into two narrower ridges which region a short distance downstream.Internally, the esker contains mostly cross-laminated sands, tough-shaped and tabular sets of cross-bedded sands and gravel, and matrix-supported sandy gravels. The cross-laminated sands occur most frequently on the flanks of northern sections and at high stratigraphic levels in the southern. The cross-bedded sands and gravels make up most of the core: in the north they area overlain by matrix-supported sandy gravels and in the south by cross-laminated sands.The reults of the investigation indicate that: a) the Norwood esker formed within a subglacial tunnel that was flowing full near the end of ablation as indicated by the upper stratigraphic position of the sliding bed, b) the larger, more complex ridge system of the Norwood esker developed within a well integrated system of channels, c) the granule layer that formed between layers of fine sand marks an erosional boundary separating sequences of lower flow velocity, and as such may provide a clue to the number of depositional units, possibly related to diurnal, seasonal and cyclonic effects on discharge, d) the fact that the sliding bed is present as two separate layers within the sedimentary column of the esker indicates that it is likely a frequent mode of transport within en- and subglacial channels.