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20 August 2022

Two erratics from coastal Maine

Happy Saturday! Here are two erratics (glacially transported boulders) that I saw last week in coastal Maine. This one shows prominent subparallel striations: And this one, in the town of Penobscot, next to the greasy spoon called Bagaduce Lunch, shows aligned feldspars that suggest magmatic flow: Nothing like a good erratic to get the weekend started off right!


22 May 2020

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…


15 May 2020

Friday fold: Argentinian turbidites

Zoltán Sylvester brings us this Friday’s fold: And there’s more where that came from: These are deepwater strata of the Lower Cretaceous Rio Mayer Formation, exposed near Lago Argentino, Argentina, south of the lake’s northwest “arm,” about here. They were deformed so exquisitely during Andean mountain-building. Zoltán is a talented photographer, and you should check out more of his work here.


17 May 2019

Friday fold: Found folds

This week, for Friday folds, I offer up some random folds that have passed my perceptual transom this week. First up: In the new Netflix series Our Planet, in episode 7 (Fresh Water), an anticline/syncline pair makes a brief appearance as David Attenborough discusses glaciers as a reservoir for fresh water. Here is a screenshot: I’m not sure where this is in the world: Greenland? Antarctica? Let me know in …


29 January 2019

The Parallel Roads of Glen Roy

What can we learn from Scotland’s Parallel Roads of Glen Roy?


20 July 2018

Friday fold: Alpine peak containing a high elevation recumbent fold

Via Twitter, a Friday fold from Maddy Rushing: #FridayFold, @callanbentley? — Maddy Rushing (@komaddyite) May 25, 2018 This is in the Alps of Switzerland; I don’t know more about it than that. If you recognize the site or the geology, educate us in the comments!


23 June 2018

Deformed conglomerate of Frog Lakes, California

Fifteen years after mapping deformed rocks of the Sierra Crest shear zone system in the high Sierra, a family vacation brings Callan back to the pre-batholith metasedimentary rocks which show a pronounced strain.


16 March 2018

Friday fold: a boulder from Spitsbergen

Today’s Friday fold comes to your eyeballs courtesy of my colleague Shelley Jaye, who took it in 1982: She found this in a glacial moraine adjacent to Lovlibreen Glacier, on the north shore of St. Jonsfjorden, Spitsbergen, Svalbard. Very cool disharmonic folding. Thanks for sharing, Shelley! Happy Friday to all.


8 February 2018

A spectacular display of Earth science in the Alabama Hills

A detailed examination of an elegant photo of the eastern front of California’s Sierra Nevada, from the perspective of the Alabama Hills. How many different geologic phenomena can be packed into a single image? Let’s find out!


7 February 2017

Basaltic strata, faulting, and glaciation in western Iceland

Today, let’s journey to Iceland, to a bit northwest of Reykjavík. This is a view from the top of the Grábrók cinder cone, across the valley to the east. With very few exceptions, Iceland is a big pile of basalt, and that shows through in the walls of this valley, which display a stack of basaltic lava flows, intercalated in places with pyroclastic debris or volcaniclastic sediment. One portion of …


24 November 2016


Scotland was glaciated during the Pleistocene “Ice Ages:” The signatures of glaciation are manifold in a scene like this. Most prominent and easily recognizable is the broad, relatively flat-bottomed U-shaped valley. Now check this one out: That’s a U-turn in a U-shaped valley: the valley is first gouged to the right, then turning around and heading in almost the reverse direction: Good things these things flow so slow, otherwise that …


13 January 2015

Glacial striations and robust hackles in Jasper

Check out the argillite boulder in the left midground of this GigaPan, which I’ve showed here before. It was taken at the Icefields Center parking area in Jasper National Park, Alberta: [gigapan id=”159489″] link There, you’ll find some lovely orange lichens, some iron oxide staining, some graffiti, and a fair number of sub-aligned glacial striations. Also, at the top edge of the boulder, there’s a nice set of big hackles, …


24 December 2014

A rock slide and a protalus rampart (?) on the trail to Helen Lake

A hike to Helen Lake, Banff National Park, Alberta, brings your intrepid geoblogger face to face with a fresh landslide and a curious landform parallel to the glacial valley. Is it a pro-talus rampart?


6 August 2014

Guest post: Glaciolacustrine deltas in the Canadian Rockies

One of Callan’s “Canadian Rockies” field course students supplies a guest post about deltas that build out into glacial lakes.


5 July 2012

Floe Lake hike

Last summer, my wife and I spent some time in the Canadian Rockies. One of the things we did was to take a three-day backpacking trip to Floe Lake, in Kootenay National Park, British Columbia. We picked a rough couple of days for hiking – We got a lot of Canadian Rockies precipitation out there: we got rained on, hailed on, and snowed on during those three days. Here’s our …


25 July 2011

Gigapan of Cascade Canyon

To follow up to my Cascade Canyon post, here’s a gigapan of the scene: [gigapan id=”82540″]


20 August 2010

The Purgatory Conglomerate

After my thesis defense at the University of Maryland, my mentor and friend E-an Zen asked me if I had ever heard of the Purgatory Conglomerate. I had not. Over the years, E-an has been a great source of new ideas and information to me, and so when he raises a notion, I pay attention. In my thesis, I had done some strain analysis on volcanic clasts in a meta-ignimbrite …