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TitleA 3-dimensional geological model of the Oak Ridges Moraine area, Ontario, Canada
AuthorSharpe, D R; Russell, H A J; Logan, C
SourceJournal of Maps vol. 2007, 2007 p. 239-253,
Alt SeriesEarth Sciences Sector, Contribution Series 20060471
PublisherInforma UK Limited
Mediaon-line; digital
File formatpdf
NTS30M/13; 30M/14; 30M/15; 30M/16NE; 30M/16NW; 31C/04SW; 31C/04NW; 31D/01; 31D/02; 31D/03; 31D/04
AreaToronto; Whitby; Aurora; Trenton; Port Hope
Lat/Long WENS -80.0000 -77.7500 44.2500 43.7500
Subjectshydrogeology; surficial geology/geomorphology; stratigraphy; groundwater; groundwater flow; groundwater resources; groundwater regimes; glacial deposits; aquifers; glacial features; drumlins; moraines; channels; meltwater channels; tills; systematic stratigraphy; till stratigraphy; lithostratigraphy; Oak Ridges Moraine; Newmarket Till; Halton Till; Lower Sediment; geographic information system; digital elevation models; Quaternary
Illustrationssketch maps; stratigraphic sections; block diagrams
ProgramGroundwater Mapping Program
AbstractThe Oak Ridges Moraine area, southern Ontario, includes most of the Greater Toronto Area, which is the most populated region of Canada. The ~ 11,000 km2 region is bounded to the south by Lake Ontario and to the north where Paleozoic bedrock abuts Precambrian Canadian Shield. The area extends 160 km eastward from the Niagara Escarpment, a prominent 100 m high regional bedrock scarp. The surficial sediment is up to 200 m thick, and reveals exposures of the oldest Quaternary sediment in southern Canada. Population growth has caused land use conflicts and increased pressure on groundwater resources. Construction of a regional 3-D geological model of the glacial stratigraphy was needed to support a better understanding of aquifer distribution, scale, and resource potential and protection. Mapping of the regional glacial geomorphology and sediment succession identified a number of distinct landforms: tunnel channels, drumlins, eskers, moraines, and till and lacustrine plains. Using sequence stratigraphic concepts, strata have been grouped into four principal units that unconformably overlie Paleozoic bedrock: Lower sediment, Newmarket Till, Oak Ridges Moraine, and Halton Till. These four Quaternary units plus bedrock have been mapped in the subsurface as a succession of interpolated surfaces using an innovative stratigraphic database-GIS approach. The model-building process involved stratigraphically coding high-quality data, then integrating an extensive and diverse array of subsurface geological and archival datasets using an expert system (geological rules). Stratigraphic data subsets were then extracted and merged with DEM-controlled surface mapping and interpolated in a GIS.