Chief Mountain; a Model Klippe

We woke up Mr. Spock this noon because, on the way to Canada, along the eastern boundary of Glacier National Park and a few miles south of the border crossing, is one of Montana's 4 geo-sites - Chief Mountain. Although he had been enjoying his summer hibernation, he was thrilled to observe and learn about this exception to the principle of superposition which posits that in an undisturbed sequence of strata, the oldest beds are positioned on the bottom and to see this model klippe - an outcrop isolated by faulting and erosion.

Standing 9,006 feet high with 1,500 feet of relief, Chief Mountain is constructed of sedimentary rocks that are of a different age and environment than the rocks of the underlying terrain. 

Mr. Spock told us that a well drilled from the mountain's crest would first engage a 1,300-million-year-old green shale and then 1,450-milllion-year-old tan and red limestone. But then, the drill bit would penetrate sandstone and shale beds deposited a mere 100 million years ago.

Yes, in Chief Mountain, ancient rocks overlie much younger strata. How is this deviation from the venerated principle explained?

Mr. Spock told us, and the cattle who came to learn, that as the forces compressing the crust in this region increased in intensity, during the building of the Rocky Mountains, the faults became overthrusted upon each other, much like the arrangement of cedar shakes covering a roof. 

The rocks of Chief Mountain were thrust up and over younger rocks sometime between 170 million years ago and 70 million years ago. During this 100-million-year time frame, a massive slab of rock was transported eastward an amazing 50 miles along one of the largest thrust faults in he world. Since then, erosion has altered the slab so that today, Chief Mountain stands completely isolated.

We are now back in Canada, in Waterton Lakes National Park. This is our view from our dinette windows, and...

this is the view out the kitchen window on the other side. This is so Canadian, putting a campground right in the middle of the mountains. Beautiful!

Last evening we observed the lunar eclipse from our Montana campground.

The "Blood" moon (looks like Mars).