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The Pinnacles: Wiggins Formation

The Pinnacles: Wiggins Formation
The Pinnacles: Wiggins Formation

The Pinnacles: Wiggins Formation

Having lived for 10 years in Jackson Hole and having taught geology in that part of the state…. I enjoy the scenery on a whole different level

One the Highway between Dubois and Moran Junction there is the “Breccia Cliff” that I’ve always known as “The Pinnacles”. They are a magnificent exposure of Volcanic Lahar flows (hot glowing cloud of volcanic debris) layered one on top of the next. It is a geology classroom all around this country but don’t try to climb that hill. It’s always having avalanches and rock falls in that country.

I’ve been up to it’s base but it took a day on horseback to do it. Do not try that on foot, it’s way further back than you think. Unforgiving country. Grizzleys hang out there now.

The rock there is basically a blender mix of tuft, scoria, a volcanic conglomerate as it were. Chunky pieces, angular all suspended in a fine grain matrix of volcanic rock. This formation is seldom found below 10,000 feet in elevation on the eastern margin of Jackson Hole. The formation is up to 3000 feet thick in this country. That’s a lot of Lahars….. You can drive right to this picture spot on Highway 287 and pull over on this meadow along the side of the road. Click

There are some wonderful lakes in this area. This is snowmobile recreational heaven in that country. Big Groomed trails along the divides cover this area. There are a few campgrounds and a lodge or two in the area. This is pristine northern Wind River Range backcountry visible right off the road.

Location: Hwy 287, 30 miles north of
Dubois on Togwatee Pass.

Title: The Pinnacles: Wiggins Formation

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Mitten Butte Volcano Illusion

Mitten Butte Volcano Illusion
Mitten Butte Volcano Illusion

Mitten Butte Volcano Illusion

SATIRE:

So I wake up the other morning and much to my surprise, was a local pyramidal hillock that was blowing it’s top. The steam was rising, the cauldron boiling. I anticipate pyroclastic flows, lahars, glowing red hot clouds and other volcanic manifestations similar to what buried Pompeii. Ash should start falling any moment. Maybe “Sneaky Pete” the windmill will save the day and blow the ash away…

Back to my normal programming: Geologic Musings:

OK, this is NOT a volcano. It takes a properly positioned camera lol. Those are normal clouds up in the sky. Yellowstone is not blowing up. The Devil’s Tower/Missouri Butte Volcanic Neck field about 50 miles to my southeast has not reactivated. No, the Laramide Orogeny has not started back up just yet.

That Butte (called Mitten Butte), is made of layers of river sands stacked on top of one another. The volcanic shape is a result of a hard cap rock which resisted erosion better than every thing else between it and myself. All that rock has been removed by erosion. It is a erosive remnant of all the material that used to surround the hill. Hundreds of feet if not thousands of feet (depending on your location) of sediment has been removed around here. Remember Devils Tower? That used to be a mile or so deep. Now it sticks up 1267 feet above the Belle Fourche River. That river system essentially removed enough material to expose the harder tower. Same process here except just the top of the hill is harder rock.

Location: Bliss Dinosaur Ranch, Wyoming/Montana borderlands (Wyotana).

Title: Mitten Butte Volcano Illusion