Friday fauxld: Sacagawea Cirque

Found this beautiful cobble while hiking Sacagawea Peak with my family yesterday, in Montana’s Bridger Range. It’s not actually folded as much as it appears to be; the laminations are slab like and nearly parallel to the surface in this photo, with the cobble surface sectioning them obliquely to produce this pattern.

Pillbug tracks in ash from Mt. St. Helens

Reader Nancy Weidman (who supplied the Wind River boudinaged basaltic dike images from earlier in the week) sent me this interesting note: Your ichnoanalogue post reminds me of the insect or pillbug tracks I found in Mt. St. Helens ash deposited in Missoula, Montana. At least some of the tracks, if I recall correctly, ended … Read more

Friday fold: Anticline in Glacier National Park

Some web research led to a serendipitous discovery and further exploration. Wherever you’re sheltering in place, you don’t have a view that’s this grand. Slip away for a few moments to the high country of Montana’s Glacier National Park, where an anticline may be seen in the towering cliffs…

Last Stand, by Michael Punke

A reader of this blog recently recommended Michael Punke’s Last Stand. I thoroughly enjoyed his novel The Revenant, and so last week I started the audiobook version of the nonfictional Last Stand (2007). Last Stand is subtitled “George Bird Grinnell, the Battle to Save the Buffalo, and the Birth of the New West.” Prior to reading … Read more

Friday fold: More kinks from Glacier National Park

This Friday, let’s return to Glacier National Park. Here are some folds in Helena Formation limestone: Can’t see them? Fair enough – the point of maximum inflection appears to be hidden behind a snow-filled gully: But in addition to that big fold, there are several kink bands in there, too. Let’s zoom in: Here they … Read more

New GIGAmacro images of rock samples

Another week, another batch of new images produced on my home-based Magnify2 imaging system from GIGAmacro. Leptaena brachiopod in (Mississippian?) limestone from Montana: Link Here’s the flip side of the same sample, with a lot of fenestrate bryozoans to see: Link Fault breccia from the Corona Heights Fault of San Francisco: Link Amygdular metabasalt from … Read more

Four new GIGAmacro images

Here are a few new images I’ve been working on with my home-based Magnify2 imaging system from GIGAmacro. Archean basement complex gneiss from the Gallatin Range of Montana: Link (If this looks familiar, that’s because one of the samples I imaged with the Photoscan 3D modeling technique and published on Sketchfab the week before last.) … Read more

Student guest post: the Belt Supergroup in Glacier National Park

As longtime readers know, late summer is when my Rockies students submit their final projects – web-based explanations of key geologic sites they examined during the trip. Today, I offer you a guest blog post by student John Leaming. You’ll notice that I’m not *completely* absent from the post, however – I make a couple … Read more

Friday fold: Yin-Yang at Swift Dam

What is Matt looking at here? Matt was one of my Rockies students this summer, a geology major at the University of Virginia. Together with another UVA student and students from Mary Washington University and George Mason University, Matt embarked on a mountain-climbing hike during our evening camping at Swift Dam, near Depuyer, Montana. The … Read more

Friday fold: a return to the duplex structure in the Gastropod Limestone

Some time ago, I featured as Friday fold the extraordinarily complex duplex structure to be seen in the Cretaceous “gastropod limestone” member of the Kootenai Formation at Sandy Hollow, Montana. Today, let’s take a deeper look through a couple of hand-shot GigaPan images: Here’s the bigger of the two: link Here’s one with students for … Read more