Sedimentology of the Brampton Esker and its Associated Deposits: An Empirical Test of Theory
Houston C. Saunderson, 1975. "Sedimentology of the Brampton Esker and its Associated Deposits: An Empirical Test of Theory", Glaciofluvial and Glaciolacustrine Sedimentation, Alan V. Jopling, Barrie C. McDonald
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The internal grain size and structural properties of the Brampton esker and its associated deposits were grouped into facies and used to test several theories of eskerine sedimentation. Each time-stratigraphic unit consisted of the following proximal to distal sequence of facies: (a) cross-bedded sand and gravel of topset origin, deposited by braided streams, or otherwise during sheetflooding; (b) delta-front sands that are poorly sorted and characterized by massive structure, graded bedding, cut-and-fill structures, irregular lamination, and parallel lamination deposited in the upper flow regime; (c) cross-laminated cosets of fine sands which show stoss-side erosion, stoss-side preservation, and sinusoidal lamination formed by the movement of climbing ripples when the suspended load contributed increasingly to sedimentation; and (d) prodeltaic rhythmites of sand and silt-clay mixtures deposited almost exclusively from suspended load. The delta-front and prodeltaic sediments represent the transition between eskerine gravels and distal rhythmites, both of which are end members of a spectrum of cogenetic deposits.
The facies associations of the Brampton area were separated into: (a) those of the esker proper, and (b) those of the associated deposits adjacent to the esker. The De Geer theory of eskerine sedimentation adequately explains the paleocurrent pattern and facies associations comprising the second group of sediments, but the kind of environment for the esker proper was probably open channel rather than closed conduit. A closed conduit flowing partly full, however, would function in the same way as an open channel.
The sedimentary environment consisted of a braided, topset network of streams that prograded into a glaciolacustrine environment between the walls of a re-entrant within the Ontario ice lobe during late Wis-consinan time.
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Glaciofluvial and Glaciolacustrine Sedimentation
This publication is the outgrowth of a symposium on Glacial Sedimentology that was held in Buffalo, New York, March 1972. The great interest generated in glacial phenomena during the nineteenth century had important implications and repercussions for the infant field of sedimentology. It provided its fair share of the background stimulus necessary to establish sedimentology as a separate branch of the earth sciences in the twentieth century. The time for reciprocity is now at hand; feedback from the expertise gained in the burgeoning field of sedimentology can greatly help the Quaternary specialist solve particular field problems. The last decade has witnessed a growing interest in the sedimentology of the Quaternary, and it seems appropriate now to summarize progress in the study of stratified drift, to present results of some recent studies, and to focus attention on avenues of research that should be explored in the near future.