You are browsing the archive for Friday Fold.
25 June 2021
Friday fold: The Blue Ridge Tunnel
Inside the Blue Ridge (in an 1850s-era railroad tunnel), Callan finds folds and boudinage that formed during Appalachian mountain-building.
11 June 2021
Friday fold: inadvertent kink fold analogue model
It’s Friday! Adam Forte, a geology professor at LSU, posted this image yesterday on Twitter: It’s a box of sheets of newsprint, stored vertically and ignored for a while, now rotated 90° so we’re looking at a cross-sectional view. To me, this is an excellent example of a physical analogue modelling experiment (albeit inadvertent) that demonstrates the process by which kink folds form. The key parameters to get this distinctive …
7 May 2021
Friday fold: Lynchburg Group
On his way to get his COVID vaccine, Callan visits a new outcrop showing folded and faulted strata of the Neoproterozoic Lynchburg Group.
16 April 2021
Friday fold: Colorado cluster
Friday means folds –
This week, we head to the Colorado Rockies for a butterfly-like presentation of a ptygmaticly folded granite dike within biotite schist.
26 March 2021
Friday folds: 3D models by Sara Carena
It’s Friday, and it’s been a few Fridays since I offered you a fold. Let me make up for that with five Friday folds today, all from the incredible collection of free 3D models by Sara Carena on Sketchfab. Sara is a senior scientist/lecturer in Geology at Ludwig-Maximilians University in Munich. Absolutely super models of absolutely super folded rocks. Well done, Sara! Viewing these should get everyone’s weekend off on …
5 February 2021
Friday fold: a new 3D model
Here’s a good sample, another one I inherited from Declan de Paor when he retired from Old Dominion University. It’s an interesting sample – I guess I’d call it a graphitic clay shale, but it’s surprisingly lightweight, so I’m not super confident that’s right. The bedding surfaces are glossy and slick, indicating some flexural slip between the layers. In terms of composition: It’s too beautiful to cut up and make …
29 January 2021
Friday fold: revisiting the Geoscience Communication Pardee Symposium
I have two Friday folds for you today, both by geovisualizers who contributed to the 2019 Geological Society of America Pardee Symposium on Geoscience Communication in Phoenix, Arizona: The first is a painting by talented geoartist Emma Theresa Jude, showing a fold at Caithness, Scotland. The fold in question can be seen at the site of Figure 5 of this paper. I love Emma’s art. What other lovely folds have you …
15 January 2021
Friday fold: Three from Alaska
Earlier this week, I was alerted to an online photo collection from the Alaska Division of Geological and Geophysical Surveys. For those of us who are feeling the lack of field work over the past year, it’s pleasant to browse through them and get a taste of backcountry Alaska. Many of the photos are shot on old slide film, but that kind of adds to the “Alaskaness” of them in …
13 November 2020
Friday fold: stairsteps in the Tonoloway
A quick “Friday fold” that is expressed in three dimensions – “stairstep” style folds deforming a bed of Tonoloway Formation dolostone…
9 October 2020
Friday fold: Torcross
Looks like we’re sticking with the U.K. for Friday folds, for the time being… This lovely beast comes to us from Torcross, via Danny Stubbs, who shared it on Twitter this past week. That’s from the Meadfoot Group of slates, cross-cut by quartz veins. In this follow-up image, Danny shares that sometimes the quartz veins have enjoyed some folding too: Happy Friday to all.
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.