Paleontology and geology

Precambrian rocks of Saskatchewan are part of the Canadian Shield, the core of the North America continent. These igneous, sedimentary, and metamorphic rocks record the presence of ancient volcanoes, islands, and ocean basins, as well as the collisions between multiple smaller continents. When several continents came together about 1.85 Ga, these rocks were pushed up into a mountain range similar to the Himalayas. Since then, they have been worn down by erosion over millions of years. The rocks are part of the Churchill Province, which has recently been divided into smaller geologic provinces or domains based on the shared histories of rocks in different regions. They range in age from the 3.1–1.1 Ga, with the oldest rocks occurring in the northwest. About 1.7–1.6 Ga, a basin developed along the edge of the newly formed continent. Sandstones, mudstones, and limestones accumulated in river, delta, and shallow marine environments in this basin. Now exposed south of Lake Athabasca, these rocks contain the only Precambrian fossils (stromatolites) in the province, as well as the richest uranium deposits in the world. Precambrian rocks in the province also yield other economically important deposits like copper, lead, and zinc.