By Mary Drew at Pasty Central (Mdrew) on Friday, July 29, 2022 - 11:31 pm:
We have featured the Natural Wall a few times before on the Pasty Cam and I always preface it with the fact that it is on private property, so it’s best to get permission from the land owners. They are pretty good about allowing folks to explore the wall.
Suyeon Griffin and her friend hiked through the woods to get to the “Ancient” Wall, known as the Natural Wall, which is part of the Keweenaw Fault. I’m not going to pretend that I know anything geological about it and instead will quote what Capt. Paul Brandes wrote about it previously.
“About the Wall itself. During the Mid-continent Rift stage as the land was being pulled apart (a modern day analog would be the East African Rift), normal faulting occurred along the edges of the rift. One of these major faults was the Keweenaw Fault, which runs the length of the peninsula. Towards the end of the rifting stage, sediments from the east and south (Jacobsville Sandstone) began to deposit along the southern edge of the basin that formed as a result of rifting. Next, a large continent sized chunk of crust began slamming into the east side of North America. This collision is known as the Grenville Orogen. During this event, compression on the Rift and Keweenaw Fault began changing the characteristics and movement of the Fault from being a normal to a high angle reverse fault. This compression also had a profound effect on the sandstone near the fault, tilting the once flat-lying beds of sandstone into vertical and even slightly backward. If one has the chance to walk the creek that flows beside the Wall, by all means do it!!! In about 1 km of walking the creek bed, you will go from flat to east dipping beds to vertical at the Wall. Of course as Mary said, you should obtain proper permission to enter and take a knowledgeable geo-person with you...hint, hint.”
If you’d like to read a bit more about the Natural Wall, head on over to Kevin Musser’s webpage by clicking here: 
