CGRG Bibliography of Canadian Geomorphology
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Author : Baker, C.L.; Lahti, L.R. and Roumbanis, D. C.
Date : 1998
Title : Urban geology of Toronto and surrouding area.
Publication : Urban Geology of Canadian Cities. Edited by: P.F. Karrow. Geological Association of Canada, Special Paper
Issue : 42:
Page(s) : 323-352.
Abstract
Urban growth and engineering practices in Metropolitan Toronto and surrounding area have been, and will continue to be influenced by the Paleozoic and Quaternary geology of the area and surface physiographic features, such as river valleys. The area is underlain by near-horizontal Late Ordovician shale-dominated units which, with the exception of poorly defined south-trending buried bedrock valleys, from a surface with relatively low relief. The oldest Quaternary unit in the area is the York Till, of probable Illinoian age, which is overlain by Sangamonian fossiliferous, interglacial deposits of the Don Formation. Early Wisconsinan time is represented by the deltaic Scarborough Formation and the glacial Sunnybrook Drift. These units are in turn overlain by the Middle Wisconsinan tills and associated deposits of the Thorncliffe Formation. Major Late Wisconsinan units include in ascending order: a lower sandy till; a coarse-grained sediment complex; Halton Till, which forms the surface unit for a large portion of the area; and Lake Iroquois glaciolacustrine deposits. Engineering problems associated with geologic materials in the Toronto area are related to the stability of naturally occurring slopes, difficulties with open cut excavations and tunnels, assessment of load-carrying capacity of foundations for structures and the use of soil or rock as engineering materials. Principal geologic conditions contributing to these problems include: ground water; weak lacustrine clays; variable soil conditions; hydrostatic pressure; buried valleys; and the stress relief/rock-squeeze properties of the shale bedrock. The basis for a geotechnical data bank in Toronto exists in the form of the 28,000 geotechnical borehole records collected in the early 1970s as part of the Urban Geological Automated Information System (UGAIS). Foremost among challenges that exist in creating a functional, operating data bank of digital geotechnical information is the need for data submission standards and the assignment of stewardship.
Bibliography of Canadian Geomorphology