Exploring an Igneous Dome in North-Central Montana – Huge Sky Walker

Into the bull’s eye.
Though I’m not a geologist, I do take pleasure in studying in regards to the processes which have formed the landscapes the place I hike and stay. As a science trainer, I’ve tried to be taught as a lot as I can in regards to the geologic setting of north-central Montana the place I educate. I wish to hike onto the panorama to get a first-hand look, then use images, maps, and different pictures to assist college students perceive why the land appears to be like the way in which it does. Google Earth has been an excellent instrument, giving my college students and I chicken’s eye views of the landforms round us. A number of years in the past I observed a wierd round characteristic on Google Earth, situated on BLM land 10 miles south of Hays. The satellite tv for pc view confirmed a really distinct collection of concentric circles, resembling an enormous goal a couple of miles throughout. Apparently, the goal form of the landform shouldn’t be noticeable from the bottom – solely from above. Some research helped me perceive the way it was fashioned, but it surely wasn’t till just lately that I ventured down there a pair instances to discover it.

Bought domes?
Some good assets helped me perceive that the characteristic is an “igneous dome”, brought on by magma forcing layers of sedimentary rock upward tens of tens of millions of years in the past. The magma by no means made it to the floor, as a substitute hardening under the layers. Within the tens of millions of years that adopted the dome has eroded, leaving the concentric round ridges of rock. Don’t get it? – The diagrams and maps within the photograph tour ought to assist. Because it seems, there are a number of domes within the space, all created by plumes of historical magma that pushed layers of rock upward – each is exclusive. In actual fact the Little Rocky Mountains north of the domes have been fashioned by magma that intruded there across the time the dinosaurs went extinct (65 mya). For extra about that, see my weblog publish titled “Wall Stroll within the Little Rockies”.

First strive.
My good friend Rick accompanied me on the primary hike into the dome on August twenty fifth. I didn’t plan an excellent route and we didn’t carry sufficient water, so we didn’t make it to the middle of the dome. I additionally underestimated how troublesome it could be to hike up and down these concentric ridges. Fortuitously, our stroll again took us under the spectacular sandstone cliffs on the southern fringe of the dome. We took a pleasant break there whereas I took some pictures with my drone and thought of a greater route for my subsequent journey.

Take Two.
Though Rick wasn’t out there to strive a second journey on September fifteenth, I used to be significantly better ready – I ate my Wheaties, received an earlier begin, carried loads of water, and deliberate a extra wise route. This time I walked alongside Bull Creek a lot of the way in which, veering off to do a clockwise loop close to the north finish of BLM land after which once more to discover the cliffs on the south finish earlier than exiting the dome. Bull Creek meanders north to south proper by the middle of the dome. Climbing alongside the dry creek mattress was straightforward however I felt like I used to be lacking out on views – plus there was some mud and some cows. On the way in which again I scrambled up a ridge to a pleasant grassy bench, after which walked over to discover the sandstone cliffs – by far the most effective a part of my day. The hike, which ended up being 12.3 miles, took 8 hours – primarily as a result of I spent a lot time exploring these attractive cliffs.

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