| Summary: | As determined from samples of cores and cuttings from boreholes that have penetrated the basement, and regional geophysical maps, the Precambrian rocks of Saskatchewan which occur beneath the Palaeozoic and later rocks consist of predominantly northtrending belts ot granitic and metamorphic rocks. The rock assemblage found in the covered Precambrian Shield appears to be similar to that mapped on the exposed Shield, consisting of belts of schists, gneisses, and intrusive rocks separated by areas of granitic rocks. K-Ar age determinations indicate orogeny about 1700 m.y., similar to the rest of the Churchill geologic province. However, minor post-Hudsonian igneous activity has occurred within the basement rocks, the apparent date of which is 1000 to 1200 m.y. The boundary of the Churchill and Superior provinces, as defined by regional gravity trends, extends southwest into Saskatchewan from the Nelson River gneissic zone, and then follows the border of Manitoba and Saskatchewan into North Dakota.
|
|---|