ABSTRACT

The mosaic of crustal domains comprising the Canadian Shield extends westward beneath the prairies to form the foundation of the Western Canada Sedimentary Basin (WCSB). Extrapolation of Shield domains and tectonic relationships into the subsurface is provided by interpretation of potential field data (aeromagnetic and gravity anomalies) and isotopic studies of cored basement (U-Pb and Nd-Sm) of the WCSB.

The western Canadian Shield, including that beneath the WCSB, can be viewed as several Archean "nuclei" or continental blocks (Superior, Rae, Hearne and Slave Provinces) that have been brought together and locally modified during Early Proterozoic collisional tectonics. The inferred history of collision and relative plate motion created several through-going structural discontinuities such as the Tabbernor Fault, Hay River Fault and Snowbird Zone that extend beneath the WCSB. The Trans-Hudson Orogen is a complex belt of Early Proterozoic crust in Manitoba and Saskatchewan that comprises the orogenic weld between the Superior Province and the Hearne Province. The Rae Province in northeastern Alberta was the western cratonic edge along which terranes of central and western Alberta were accreted during the Early Proterozoic.

The wavelength and scale of the Williston and Alberta basins is much larger than those of tectonic elements of the basement, suggesting that basement structure did not exert a first-order control on the location and development of these basins. However, improved understanding of basement structure through potential field and seismic methods, will provide key data on the potential role of basement structure on smaller wavelength structures in the WCSB.

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