Close Encounter with a Laccolith

I went on something of a side-trip yesterday, accompanying fellow Jentel residents Ryan and Joe on a little excursion to Devils Tower, a point of geologic interest located in the northeast corner of Wyoming. This is, of course, the big cylindrical rock formation that… well, it’s featured fairly prominently in a movie, I suppose. Otherwise I’m not sure how well known it is outside of the western United States, since it feels like it’s somewhat iconic around here.

It really is the tallest thing in the area, rising some 1200 ft. from the surrounding terrain, and having a summit at about 5100 ft. above sea level. The area where it’s situated is actually pretty nice on its own– there’s a bright red canyon nearby that the river flows through, amongst pine forest. In fact, it seems reminiscent of what the Moab/Arches area was like several million years ago, when it was apparently more of a pine forest than dry desert. Does that red sandstone have any geologic relationship to the terrain of Arches? I suppose I’d have to ask a geologist to know. I find geology somewhat interesting, at least in a casual sense, but I have to confess that I kind of start to zone out the way it’s often presented. It’s a subject with which I should educate myself a bit better at some point in the future, since I more often find myself interested in the ecological history of an area, rather than the literal rock composition.

For example, at the time of the Tower’s formation way back in olden times (40 million years ago, I guess?), all of the signs seemed to indicate that ground level for the area was over a mile and a half above our head, and erosion gradually made the current ground (and the Tower) what it is today. Where did all of that material go? And where did it come from? Is it just sort of evenly spread over the Great Plains, and at the bottom of the Gulf of Mexico? Maybe areas like Louisiana were gradually formed by this “missing” material being washed down the rivers millions of years ago. Once again, it’s a great question for a geologist, but I don’t have one of those handy right now.

But, as I said, I often find my mind wandering to what things were like on the surface in those long-past epochs. Was it a terrain where dinosaurs roamed, or was it sea floor? Or both, during a billion-year period? The world is a pretty amazing place right now, and I can’t help but wonder how many amazing things, like caves and canyons, were formed and destroyed during the passage of time, and how many more are yet to come in the future. Things like continental drift allow us to at least predict some effects… if I remember the Natural History Museum in London correctly, London will be approximately where the North Pole (or at least much of Greenland) is in about 200 million years, so life in England will probably be quite a bit different. But will it be more mountainous, or less? Maybe it will be underwater, or a new Tibetan plateau. Maybe giant hamsters with eyestalks and acid-spraying tusks will live there, or maybe it will be inhabited only by wooly turtles that eat lichen. Maybe it will have a giant dome over it, and be pretty much the way it is today, carefully maintained by people who wear colorful robes, because they live in the future.

So, as you can see, my mind wanders away from pure rocks pretty quickly. Still, there are some neat rocks on the site, and the base is strewn with chunks of those big columns that have fractured off over the years, many of which are the “usual” boulder size, but many are about the same size as a buses and cars.

We weren’t at the site too long, but we did take time to hike around the base of the tower, and contemplate our surroundings. It was somewhat snowy, making our trek a bit trickier than it would have been in the summer, but as far as snow hiking goes, it was pretty ideal. I don’t think any of us slipped and feel down or anything! I have a feeling there aren’t any pika living in the rocks at the base of the tower, since the visitor’s center probably would have mentioned them if there were, but we did see some prairie dogs out and about further down at the valley floor.

So, if you’re passing through the area sometime, you should stop by and check it out, since it’s only about a 30-mile side-trip from I-90.

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