Since I was already in Grand Marais I decided that I would finally make my way up to Judge C. R. Magney State Park and visit the Devil’s Kettle.
The Devils Kettle is an interesting formation. The area is dominated by coherent basalts, but in the area of the creek there is a marked weakness in the strata, where as the material goes from a massive basalt to a more granulated structure dominated by centimeter sized cubes of material. This causes a relative weakness which has largely been eroded out by the creek.
If you look at the tourist manual you will have a description that states that the entire area is basalt flows, one on top of another. This is a description that does a good job of describing most of the north shore of Lake Superior, however while I was up at a cabin on the Gunflint I happened to run into a guide to Cook County geology which shows the are as a rhyolite formation. The transition between these two formations, especially if one was embayed within the other, would explain much of the weakness. I would have gladly explored this translation myself, but I was limited to staying on the trails and did not feel like getting kicked out of the park for dismantling things with a rock hammer.
Many people have tried to determine how the Devil’s Kettle actually works. People have suggested that it runs down a lava tube, and many other possible explanations. After looking at it myself I would have to guess that it is actually feeding into a large aquifer that is corresponding to the zone of weakness at the contact zone between the basalt and the granulated rhyolite.
I could be completely wrong, but it is my thirty second translation.
Anyway here are some pictures!