Have a gander at this: Given that this is a Friday on Mountain Beltway, you might expect to see a fold here, and indeed, there’s something wavy and high-contrast running through the center of this sample. But that’s no fold. It’s a fossil plant! A “reed” of some kind, I guess. You can also see … Read more
As with last week, the Friday fold comes from my Field Studies in Geology class to Sideling Hill and the Paw Paw Tunnel. This is a view of the downstream (north) entrance to the Tunnel, with students highlighting the trace of bedding in the turbidites of the Brallier Formation: Can’t make it all out? Let’s … Read more
Here’s what the Sideling Hill road cut looked like last month: It’s a terrific example of a syncline. Usually I show folds in profile view, but here, the view is essentially perpendicular (not parallel) to the axis of the fold: Sideling Hill’s rocks are early Mississippian in age, made of debris shed off the late … Read more
My student James O’Brien took this image of a kink band along the Billy Goat Trail, downstream of Great Falls in Maryland’s metamorphic Piedmont province. A lovely little structure, don’t you think? Thanks, James! Happy Friday, all.
We have a guest Friday fold today, from reader Ben Mackay-Scollay of the Monash University School of Geosciences in Melbourne: Ben writes: Hey there Professor Bentley, been a fan of your blog for a while and I thought you might be able to use this for your Friday Fold series. It’s an upright fold at … Read more
It’s Friday… that means it’s time for a fold. Let’s try this outcrop at “Confusion Hill” in the Franklin Mountains of West Texas: See it? Let’s zoom in… From the shadows to the left of the hammer, trace out the dark green layer… it may make you think of a box fold: …but it’s not. … Read more
I know nothing about this sample, other than the fact that it was a thrown-away sample found in the rock pile next to the old geology building at the University of Texas at El Paso. Happy Friday!
Happy Friday! Here’s a beautiful folded obsidian sample, replete with conchoidal fractures, on display outside the geology department at Arizona State University in Tempe, where I was last week:
For the Friday fold, let’s journey back to the Silurian, as exposed in the limestones of that age that were deformed during Alleghanian mountain-building (Pennsylvanian and Permian), and exposed along Corridor H in eastern West Virginia. Some buckling (cuspate-lobate form) seen in that one… A little pop-up with hinge collapse: And, finally, as a digestif, … Read more
Howard Allen, a blog reader from Canada, digitized a bunch of folds for us from his old Kodachrome slides. You’ll be seeing selections from these images over the weeks to come. Get psyched! There are some great folds in this batch. Here’s the first: Howard’s description: 3D folded marble, Shuswap Metamorphic Complex, north of Sicamous, … Read more