15 March 2013
Friday fold: a recumbent anticline in an abandoned quarry
Posted by Callan Bentley
Yesterday, I spent a pleasant day in the field with John Singleton, the new structural geology professor at George Mason University. I was showing John a couple of sites I’ve used as field trip locations for the GMU structural geology class, and John was showing a couple of new sites to me – places he visited on last fall’s Virginia Geological Field Conference. I missed VGFC last fall, as I had something else going on that weekend, so I was pleased to finally get to see these new sites. Today’s “Friday fold” is one that the conference participants kept talking about long after the conference was over: a recumbent anticline in a quarry on the northeast shore of the South Fork of the Shenandoah River. The quarry unfortunately has a lot of trees in it these days, but the fold is still plenty clear.
Two GigaPans of the site:
The axial surface of these folds (there’s a more obscure recumbent syncline at the bottom of the quarry wall) is more or less horizontal. This is unusual in the Appalachian Mountains’ Valley & Ridge province. Usually the folds are upright. So why is this one different? Steve Whitmeyer of James Madison University and his students interpret it as formerly having been upright, but then it got rotated over to the west due to a cryptic west-directed thrust fault (with these rocks being in the footwall of that putative fault).
Is there movement toward making Gigapans available via HTML5 techniques instead of Flash? Tis a disappointment for mobile visitors to see nothing of interest on the Friday Fold page 🙁
Paul, here’s what I do on my iPad: I click the “link” below each GigaPan, that takes me to the GigaPan site, where it says “you need Flash, or for iOS devices, click here” and then I click there, and it opens it up in some other format, I guess HTML5. Extra steps, to be sure – but hopefully you’ll find the opportunity to explore worth the trouble of that pair of extra clicks.
My non-IOS mobile device just doesn’t show anything but a blank screen where the gigapan is supposed to be, just FYI. (But then, I need a newer device, obviously.)
What happens when you click the link to the GigaPan webpage? Does it give you any options?
I can go to your user/profile page, can then click “view all of Callan Bentley’s gigapans,” then can use a search box. It’s an older Windows Mobile type setup; can’t see anything for videos or gigapans. Not really worth worrying about, but a snapshot like your 2nd post works better currently.
Now the only question for me is, android or iph0ne4/5?