Geology of Voyageurs National Park

You can clearly see some of the worlds oldest rocks right here in Voyageurs National Park. The park is situated right at the southern side of what is known as the Canadian Shield, a huge rock basement which has a great selection of Precambrian rocks, the oldest rocks in North America. When we say old, we mean old, we’re talking rocks from between 2.5 to around 4.5 billion years ago generated due to the tectonic plate processes in the continental crust.  These early rocks are only evident in Wyoming, Minnesota, Greenland and some areas of Canada – and Voyageurs National Park is a great place for geologists and budding geologists to study them.

The Precambrian period is divided between two eons, the Archean period which dates from around 3,800 – 2.5 million years, the the Proterozoic which is from 2,500 to 540 million years ago. The majority of the rocks found in Voyageurs National Park are the metamorphic and igneous rocks from the Archean age, the metamorphic rocks in the central and western parts of the park, and the igneous rocks in the southeast and eastern parts of the park.

The area of Voyageurs National Park went through at least four different glaciation periods, starting around 190,000 years ago, which carved and shaped the very base of the landscape which is still evident to visitors to this day.  These glaciers scooped out countless lake basins as well as scraping the rock surfaces dragging lots of loose rocks across the surface resulting in outwashes and lakes. This is responsible for today’s varied, rugged topography including the rolling hills, slopes and bedrock outcrops scattered between the various beaver ponds, bogs, islands, swamps, small lake and the larger four lakes in Voyageurs National Park.