undifferentiated rock units

Paleontology and geology

Precambrian rocks comprise most of the exposed bedrock of Nunavut and underlie younger rocks in the rest of the territory. They have been divided into geologic provinces based on their shared histories, but together they form part of the Canadian Shield, the core of the North American continent. The oldest rocks date back to over 3 Ga, and they represent many different islands, oceans, mountains, volcanoes, and continents that developed, collided, and broke apart over billions of years. These rocks contain fossils of some of the oldest stromatolites, as well as many economically important mineral deposits. By the end of the Precambrian, after all these pieces came together to form early North America (Laurentia), they were surrounded by shallow seas, where sandstones, shales, and limestones were deposited.