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2001. M.Sc., 174 pp.
QUANTIFICATION OF THE SAND AND GRAVEL QUALITIES ALONG THE
GUELPH OUTWASH, SOUTHERN ONTARIO
Heymers L.
 The
Late Pleistocene Caledon-Guelph outwash has developed in front of the Paris
Moraine from Caledon to Guelph and to Paris in southwestern Ontario. Its
sediments were transported and deposited by braided meltwater streams that
flowed quasi-parallel to the front of the Ontario lobe of the Laurentide Ice
Sheet. These streams received input of sediment and water from various points
along their path, and never developed a graded profile. They were also affected
by strongly variable discharge related to variation in thaw in different seasons
and from day and night. Occasional bursts of ice-dammed supra- and/or
sub-glacial lakes may have triggered short-lived but powerful mega-floods. These
events led to a complex distribution of variable deposits of sand and gravel. As
a result, these deposits maintain the record of events and processes active in
these glacial marginal environments. These sand and gravel deposits were studied
in four representative pits: Caledon, Erin, Martini (within the outwash), and
the Leslie pit (within an ice-contact zone). Stagnant water conditions are
revealed by few local occurrences of silt and fine sand layers. Braided stream
conditions, with continuous cutting and filling of channels, is revealed by the
alternation of massive sandy gravels and cross-bedded deposits. Evidence of
extremely large magnitude floods is recorded by the presence of imbricated
coarse boulders, large foresetted deposits, and large channel fills,
particularly in the Caledon region.
The Caledon-Guelph outwash is an
economically important aggregate deposit. The deposits are valuable because of
their quantity and quality. They are thick, lack deleterious lithologies,
usually require limited processing, are located near transportation routes, and
major market areas.
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