CGRG Bibliography of Canadian Geomorphology
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Author : Dekeyser, L-K.; Eyles, C.H.; and Bajc, A.
Date : 2004.
Title : Quaternary geology of the Forwell Pit, Breslau, Ontario.
Publication : 49th Annual Meeting of the Geological Association and the Mineralogical Association of Canada. May 12-14, 2004. Brock University, St. Catharines, Ontario.
Issue :
Page(s) :
Abstract
The Forwell sand and gravel pit in Breslau, Ontario provides excellent exposures through the complex assemblage of Quaternary deposits that underlie the Waterloo region of southern Ontario. These deposits contain a rich record of paleoenvironmental change during the late Quaternary and may be used to reconstruct spatial changes in the position of the southern margin of the Laurentide Ice Sheet. Quaternary deposits in this region are host to productive aquifers used for municipal drinking water sources. An understanding of the three-dimensional distribution of subsurface sediment units is necessary for the effective protection and development of these aquifers. Paleozoic bedrock in the Waterloo region is overlain by up to 90 m of Quaternary sediments but there are relatively few exposures through these deposits. The Forwell pit is an active sand and gravel quarry that covers an area of over 1.5 km2 and exposes a 28 m-thick succession of Quaternary sediments. Coarse-grained, relatively poorly-sorted gravels interbedded with sands and fines are exposed at the base of the pit and are interpreted to record ice-proximal glaciofluvial and glaciolacustrine deposition. These deposits are overlain by three distinct diamicts separated by discontinuous sands or fines; diamicts probably record episodes of glacial advance across the region during the Nissouri and Port Bruce Stadials. The stratigraphic position and lithological characteristics of the lowermost diamict suggest that it may be equivalent to the Catfish Creek Till. This diamict is relatively coarse-grained and may contain reworked glaciofluvial deposits. The second diamict exposed in the succession is relatively fine-grained, appears to consist of reworked glaciolacustrine materials and may be equivalent to Maryhill Till. The uppermost diamict exposed in the pit shows similar characteristics to diamict that veneers the nearby Breslau Moraine and is interpreted as the Port Stanley Till. Interbedded sands, gravels and fines, interpreted previously as glaciofluvial deposits, form the uppermost deposits exposed in the Forwell pit. The distribution of coarse- and fine-grained Quaternary sediment types in the Forwell pit may be used to create a three-dimensional depositional model that has application for prediction of the subsurface distribution of aquifers and aquitards elsewhere in the Waterloo region.
Bibliography of Canadian Geomorphology