Ok, now I'm blogging about Minnesota geology. There is an ongoing search for the original granitic crust, which is elusive. It is possible it doesn't exist anymore. It may have been eroded and recycled. It's also possible that the original crust was basaltic. One of the difficulties is that most of Minnesota is covered with glacial drift. The Canadian shield contains many belts of volcanic and sedimentary rock. It has been suggested that the belts are the uplifted remnants of the "basement", the structure upon which the volcanic-sedimentary features were built. But that doesn't mean they are the original crust.
It is likely that the very early days of Minnesota were ones of violent volcanic activit