wyoming

Plane views: Powder River Basin and Black Hills

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Happy fourth of July! Here’s two scenes that are emblematic of America, as seen from my airplane window last March flying from Reno to Minneapolis. Here’s the scene in the central Powder River Basin of eastern Wyoming: If you zoom in, you’ll see what caught my eye – regular rectangular excavations into the surface. These … Read more

Friday fold: an asymmetric anticline from Wyoming

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Another landform seen out the window of that very productive photo-flight last March: That’s a breached plunging anticline – doubtless a Laramide structure. This was over Wyoming; I think here. Looking north-ish, along the axis of the fold: Note that the lengths of section line A and B are not equal: this anticline is asymmetric. … Read more

Pebble Creek memories

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This summer is the first summer in half a decade that I won’t be spending time camping at Pebble Creek campground, in the Lamar Valley of northeastern Yellowstone (“America’s Serengeti”). While I’m very excited to be nesting and exploring my new home in the Fort Valley, it does make me a bit wistful to think … Read more

Plane views: Wyoming

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I wanted to pick up where I left off months ago with some airplane photos as I was flying back from my California field class (over spring break). All views are to the north (out the left side of the airplane as we flew from Reno to Minneapolis). We crossed from northern Nevada into Wyoming, … Read more

Plane views

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Some views from the airplane, over southern Wyoming (first two photos) and north-central Nevada (last four), last Saturday morning… A canyon: …and zooming in to the middle area of the previous photo: Strata upwarped into a structural dome (that has been “planed off” to be topographically horizontal, revealing a bull’s-eye-shaped outcrop pattern, then differentially weathered … Read more

Cross-bedding in Flathead Sandstone, Wind River Canyon

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This is a boulder of Cambrian-aged Flathead Sandstone, the unit overlying the Great Unconformity exposed in Wind River Canyon, Wyoming. Click to make it 5000 pixels wide. Swiss Army knife for scale. It shows a lovely example of multiple upside-down cross-beds. It also shows a heavy layer of caliche on what is (now) the upper … Read more

Two Sisters

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All this talk about footprints and tail traces, and I haven’t even shown you any “for sure” dinosaur fossils. Well, let’s remedy that today. We return now to the scene: exposures of the Jurassic Morrison Formation, on the east side of the Bighorn Basin, just north of Shell, Wyoming. I was wandering around, finding things … Read more

Tall tail

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Okay, so I was out photographing ripples and admiring lichens, and then I saw this: That’s a rippled slab of sandstone, but with a linear groove that obliquely cross-cuts the ripple marks. Smaller, parallel grooves lie within the main groove. Here’s another look at that same one, spun around and zoomed-in: It looks as if … Read more

Ripple marks and cross beds in the Morrison Formation

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This past summer, the day after my examination of basement complex along the Colorado/Wyoming border, I drove north to Greybull, and then with Virginia Museum of Natural History paleontologist Butch Dooley to a dinosaur dig site north of Shell, Wyoming. There, in the Bighorn Basin west of the Bighorn Mountains, are dinosaur-bearing exposures of the … Read more

Pilot Peak: a classic horn

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Along the Beartooth Highway, east of Cooke City, Montana, you will see this striking mountain: Click through to make it really big. That’s Pilot Peak. It’s a horn in Wyoming. My Rockies students get really jazzed when they see it. Glaciers carved away the rest of the mountain, leaving only this pyramidal spire. Awesome.

Clinker

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“Clinker” is an interesting rock type seen in Wyoming’s Powder River Basin. It forms when a coal seam catches fire, and cooks the rock above and below it, including the potential for partially melting the strata immediately above. Check out a few images of this intriguing rock here.

Split concretion

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Concentrically-zoned ironstone concretion in sandstone of the Morrison Formation, eastern flank of the Bighorn Mountains / western edge of the Powder River Basin, Wyoming, at the Sheridan College dinosaur fossil quarry, last week. The white stuff is caliche. A quick post to celebrate the fact that as of three hours ago, Lily & I are … Read more