Wall stroll within the Little Rockies – northcentral Montana

Fairly the again yard.
Lengthy earlier than I turned a avid hiker, I used to be drawn to the spectacular limestone bluffs on the northwestern fringe of the Little Rockies. After I taught in Harlem 40 miles north of right here within the mid-1980’s my spouse and I often visited mates on their ranch a mile north of the cliffs. Lastly sooner or later I walked to the bottom of the cliffs and located my option to the prime. It instantly turned one among my favourite locations. Since popping out of retirement in mid-December 2019 to show in near-by Hays, I’ve been in a position to stroll alongside the cliffs a number of instances.

What’s up with these tilted slabs?
In case you’ve ever pushed southward throughout the Fort Belknap Reservation on a summer season night because the tilted slabs of limestone are catching the late-day daylight, you perceive the attraction (see picture beneath). What hiker wouldn’t need to stand up there and take a look? On my three most up-to-date visits to the cliffs I took a number of drone images – These, together with many different images, diagrams, maps, and Google Earth photos are included within the photo tour. I’m not gonna lie – there are some actually good images within the tour, so it gained’t damage my emotions in the event you go there now. Nonetheless, if you wish to know why there’s a wall of limestone across the Little Rockies, proceed studying.

Almost-vertical limestone cliffs like this encompass the Little Rockies, an island mountain vary in northcentral Montana.

Tropical Montana.
I’m fascinated with the scenic panorama of the Fort Belknap Reservation, in order a science instructor I’ve discovered as a lot as I can in regards to the geology of the world. Right here’s what I do know in regards to the wall . . . The cliffs are fabricated from almost vertical layers of Madison limestone, fashioned from sediment that was deposited throughout the Mississippian Interval about 320-360 million years in the past. Thick deposits of corals, shells, and different types of calcium carbonate gathered on the ground of a shallow tropical sea when this a part of Earth’s crust was a lot nearer to the equator. The Madison limestone makes a significant contribution to the surroundings of Montana – The Gates of the Mountains, the Rocky Mountain Entrance, Lewis and Clark Caverns, Sluice Packing containers, and Bighorn Canyon are all fabricated from (solely or partially) Madison limestone.

The remainder of the story.
The sediment was deposited in horizontal layers, ultimately turned rock, and was lined by youthful layers, which additionally turned rock (sandstones and shales). Then about about 60 million years in the past magma labored its method towards the floor, inflicting the layers to be domed upward. The magma hardened, changing into the igneous rock discovered on the core of the mountain vary. The doming occurred in an space about 15-20 miles in diameter. Over time, many of the limestone and different layers above the igneous intrusion eroded away, leaving solely the steeply-tilted fringe of the limestone dome that types the cliffs proven within the picture and different related outcrops across the perimeter of the Little Rockies. Hey! Thanks for sticking with me! Now go benefit from the picture tour. 🙂

Beneath: This map marks hikes which were featured on bigskywalker.com to this point, together with a number of in Glacier Park – Choose full display to develop, zoom in for extra element, or click on on a marker for a hyperlink to the submit.