In my research, I have had the pleasure of focusing many projects in the area located on the border between Minnesota and Ontario near the general region of Rainy Lake. This area is part of the Superior Province, the world's largest contiguous Archean granite-greenstone terrane. The tectonic history of this area (one version of it) began approximately 2.7 billion years ago when a series of volcanic island arcs collided into one another creating a classic Archean granite-greenstone terrane. Between two of these island arc subprovinces, the Wawa and the Wabigoon, lie the Quetico metasediments that were probably deformed during the collision.
At this boundary between the Quetico and Wabigoon subprovinces, the rocks have undergone a prolonged history of deformation. The rocks at the boundary have undergone ductile deformation as evidenced by their prominent foliation and lineation mineral fabrics. Two major shear zones, the Seine River- Rainy Lake and the Quetico, localize deformation.
Hop on the bus to any of the stops below:
Seine River Conglomerates: ***The World's Prettiest Rocks: Check these out first!***
The Ottertail Pluton