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7 August 2020
Friday fold: syncline in Helderberg Group limestones
I went on a day of field work last week to Corridor H, West Virginia, to help make drone-based photogrammetric 3D models of the huge outcrops there. One site we stopped at is this beautiful V-shaped syncline in Devonian-aged Helderberg Group limestones. Click to enlarge Here are two layers traced out: Here is a GigaPan that Alan Pitts shot of this outcrop several years ago, when it was a bit …
31 July 2020
Friday fold: Two Mile Run Overlook
I spied an anticline last weekend while engaging in a day of solo geologizing along Skyline Drive in Shenandoah National Park. At Two Mile Run Overlook, I gazed west toward the southern tip of Massanutten Mountain, and noted what appeared to be an anticline in the Blue Ridge foothills: Annotated: And here it is in Google Maps, with the perspective rotated to looking ~along strike to the north, and I …
24 July 2020
Friday fold: Totier Creek phyllite
Exploring his new digs in Charlottesville, Callan is introduced to a large exposure of phyllite at a dam’s spillway. The foliation there is folded in many ways. Share in a dozen field photos of the site…
17 July 2020
Friday fold: Sandy Hollow from the air
The Friday fold is spied below, in the Montanan landscape near Dillon, from an airplane high above…
10 July 2020
Friday fold: Candigliano River, Italy
Reader Michael Hiteshaw spotted some amazing folds this week while watching Kayak Session TV on YouTube. Though there’s a dramatic arc of “saving” a deer, both Michael and I felt our eyes drawn to the canyon walls where there are gorgeous folds in several sizes and shapes, with an emphasis on chevron folds: The video description on YouTube reads: Fabulous action by whitewater kayaker Fabrizio “Gass” Capizzo who saved …
19 June 2020
Friday fold: Scaglia Rossa chevrons at Lago di Fiastra
My friend Alan Pitts is orchestrating a virtual field camp for George Mason University this summer, utilizing outcrops in central Italy’s Apennine Mountains. Here’s a 3D model he just posted of one of the most impressive outcrops there: the chevron folds in the Scaglia Rossa limestones at Lago di Fiastra. I featured the site as a Friday fold 3 years ago when Alan took me there in person, but this …
5 June 2020
Friday fold: Harbledown Island
Reader Christian Gronau writes with this Friday fold contribution: Greetings from Cortes Island, BC – at the opposite end of the Strait vis-a-vis Lopez Island. Your Mountain Beltway blog is always of interest, and I have been following it for several years by now. Thank you for putting the effort into this worthwhile website. Quite regularly your posts elicit “echoes” and make me go back to some of my own …
29 May 2020
Friday fold: Lopez Island tension gashes
The Friday fold shows some sheared quartz-filled tension gashes in sandstones of one of the San Juan Islands in Puget Sound.
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.
Callan Bentley teaches geology at Piedmont Virginia Community College in Charlottesville, Virginia. He is a Fellow of the Geological Society of America. For his work on this blog, the National Association of Geoscience Teachers recognized him with the James Shea Award. He has also won the Outstanding Faculty Award from the State Council on Higher Education in Virginia, and the Biggs Award for Excellence in Geoscience Teaching from the Geoscience Education Division of the Geological Society of America. In previous years, Callan served as a contributing editor at EARTH magazine, President of the Geological Society of Washington and President the Geo2YC division of NAGT.