Callan Bentley This week is “Wyoming Energy Resources field trip” week! Day Start End Destination August 1st Sheridan, WY Lander, WY Gas Hills Uranium District August 2nd Lander, WY Lander, WY Green River Basin Oil Shale and South Pass/ Atlantic City Mining District August 3rd Lander, WY Newcastle, WY Smith Ranch-Highland Uranium ISR Mine and Mill near … Read more
Lily poses with amphibolite boudin (showing extensional veins) on the road in Kootenay Bay, British Columbia.
Here’s a contest for you: tell me what all the following items have in common. Though there are several sub-themes (readily apparent), I’m looking for the one overriding commonality for all the following 105 items: Hi-Lo Inferno The Good Life Country Squire Wildcat Wilderness Challenger Flair Catalina Sport Alpine Coach Designer Carriage Maxum Wildlife Artic … Read more
On my hike to the Burgess Shale earlier this week, we encountered some great geology as well as paleontology. For instance, consider this rather epic alluvial fan, spilling out of the Presidential Range to the northwest of Fossil Ridge and Mount Burgess, and rapidly filling the Emerald Lake basin. Here’s a Google Map link to … Read more
Folded quartzofeldspathic vein in amphibolite, Wyoming Terrane basement complex, Montana.
Here is a trio of concentrically-zoned chert nodules in Mississippian Castle Reef Dolostone, exposed at Sun River Canyon, Montana, just downstream from the roadside outcrop of the French Thrust: If you look closely at the lowermost of the three chert nodules, you’ll see it’s been split and offset by a small fault. Here are close-up … Read more
All my Rockies students would agree. Just sayin’.
To follow up to my Cascade Canyon post, here’s a gigapan of the scene:
Dave Lageson of Montana State University and I ran into each on our respective field trips sometime last year outside of the Two Medicine Dinosaur Center in Bynum, Montana, and he told me that I had to go check out the Swift Dam area, a little ways northwest of the town of Depuyer. So, a … Read more
That’s my Rockies co-instructor Pete Berquist, in the regulation uniform of an orange down vest, holding a subtly-folded slab of sandstone (it’s a very slight “S”), rescued from amid the shaley wastes of the Blackleaf Formation, the Cretaceous aged sedimentary rocks beneath the Lewis Thrust on the Blackfoot Reservation, just east of Glacier National Park. … Read more
Today, the Friday fold is a fake! Looks like a nice set of asymmetric antiforms and synforms, right? But it ain’t! It’s naturally wiggly; primary not tectonic. The photo shows nothing more than differential erosion of hematite that was deposited by groundwater in permeable sandstone. It’s Liesegang banding! These hematite blobs are in the sandstone … Read more
Stylolites (pressure solution seams) in limestone of Mississippian age, exposed on the side of a rounded boulder in Hyalite Canyon, Gallatin Range, Montana. These stylolites, like most, are bedding-parallel, and thus most likely formed due to the weight of the overlying rock. Calcite, the dominant mineral, goes into solution under pressure, and insoluble material, like … Read more
Cretaceous sandstone layers, exposed on the Blackfeet Reservation (Montana route 49), east of Glacier National Park, Montana. Apparently these two are the opposite halves of the same jointed block.
Following up on Friday’s fold, I wanted to share a few other images from our hike last week in Cascade Canyon of Grand Teton National Park. Lots of cool exposures of Archean basement rock there. Folds in gneissic banding: Big, angular mafic blocks in a felsic soup: Swarm of granite dikes on a mountainside: Asymmetric … Read more
Spotted this in Cascade Canyon, in the Tetons of Wyoming, last weekend: Nice asymmetric antiforms and synforms in the gneissic layering of the Archean basement rocks exposed there. Also, we saw a bull moose. More on that later on, when I get more time.
The other day, driving south through Yellowstone on our way to the Tetons, I stopped to give my students the obligatory look over Yellowstone Lake’s West Thumb, looking east towards the snowcapped Absaroka Range in the distance. But in addition to a lovely view and a few birds, we found something really cool… Those are … Read more
While out in the field with Butch Dooley last week, making major discoveries like I do, I was very impressed with the landscape-scale west Bighorn monocline, which takes formerly horizontal Madison limestone and skews it to a westward dip where the mountains end and the intermontane basin begins. It’s totally sweet. Check it out in photo form and gigapan, too.
This year, for the first time ever, I took students to map at Block Mountain, a classic field camp mapping site near Dillon, Montana. Here’s a quick look (enlarge it by a gazillion-fold by clicking through) of some columnar jointing in the Eocene Block Mountain basalt flow, a paleo-drainage turned mountain through the miracle of … Read more
Our field class visited the Museum of the Rockies yesterday. Here’s the full team!