A couple of weeks ago, I was killing time down in Front Royal, and I spent a pleasant hour in the Royal Oak Bookshop. I saw a used paperback copy of Tony Horwitz’s classic Confederates in the Attic there, and bought it, thinking I could give it away to a friend or visitor who didn’t … Read more
Callan describes the geology along his new commute from the Fort Valley east to the Annandale campus of NOVA. The driving route traverses the Valley & Ridge, Blue Ridge, and Piedmont provinces, including the Culpeper Basin, and stops just shy of the Coastal Plain.
Here’s another video, wherein I’ve made some improvements from the last one (reserved the lower right corner for the webcam “talking head” video inset, and adjusted the microphone for fewer audio blowouts). It’s still not perfect – there’s a disconnect between the audio and the webcam video that becomes more and more pronounced throughout the … Read more
Callan presents a collection of well-exposed amygdules, seen along the Dark Hollow Falls trail in Shenandoah National Park, Virginia. These white dots on a green background are the signatures of (1) Iapetan rifting, and (2) Alleghanian metamorphism.
I’m playing around with Microsoft Expression screen capture for the book project I’m working on, and here is a video I worked up yesterday as a demonstration of this new way of telling a geologic story: The Grenville Orogeny and the rifting of Rodinia (opening of the Iapetus Ocean): [youtube=”www.youtube.com/watch?v=g6itZWD8bQc”] I’m frustrated by the way … Read more
I’m cleaning out my backlog of old photos. Here’s some small living things that I’ve taken pictures of in the relatively recent past… Let’s start with two butterflies in the Gallatin Range, Montana: Returning to Virginia, here’s a fuzzy little white moth: A crane fly is next… (M.A.G.I.C. has been churning out lots of crane … Read more
Further upstream from the Skolithos and the snake and the diabase rip-rap… The field review team wandered down onto a creekside outcrop of Antietam Formation. The Antietam is a quartz sandstone, with variable levels of deformation, depending on where you look. In some places, it has been gently strained with the little Skolithos tubes taking … Read more
The word “Shenandoah” is thought to mean “daughter of the stars,” a lovely turn of phrase even if there’s no evidence for it. The name has been applied to a variety of features in the Commonwealth of Virginia. One is the Shenandoah River, and the valley in which it flows. Here’s a look at the … Read more
Handwritten notes by Ernst Cloos (legendary structural geologist from Johns Hopkins University) on the area I visited last Monday on a field review of the new geologic map of the Elkton East quadrangle by Chelsea Jenkins, Chuck Bailey, Mary Cox and Grace Dawson.
As I mentioned, Monday had me out in the field, looking at the western Blue Ridge and eastern Valley & Ridge provinces in Virginia. This was a field review for the new geologic map of the Elkton East quadrangle by Chelsea Jenkins, Chuck Bailey, Mary Cox, and Grace Dawson. Immediately after lunch, we visited an … Read more
On Monday, I was out in the field at the Blue Ridge / Valley & Ridge transition (“boundary”?) in the Elkton East quadrangle, where Chuck Bailey and students (from the College of William & Mary) were leading a field review of their new geologic map. A field review is a form of field-based peer review, … Read more
Last Saturday, before the rains moved in…
Lily and I went out to look at houses last weekend, and I couldn’t help but take some photos of cool rocks I saw along the route. See if you can identify / name / interpret all four: And here’s a bonus: Can anyone tell me what kind of bird built this diminutive nest?
I collected this sample the weekend before last on the Blue Ridge Thrust Fault field trip led by Alan Pitts. It’s a chunk of the Antietam Formation quartz sandstone, a Cambrian beach deposit. The face we photographed measures 15 cm by 12 cm. link It definitely looks best in full screen mode, so please feel … Read more
One of Callan’s former students leads a field trip to examine the western edge of the Blue Ridge geologic province, attempting to answer the question of whether the Blue Ridge / Valley & Ridge contact is indeed the trace of a thrust fault. Breccias and S-C fabrics tell part of the story…
Had this brainstorm a few weeks back (or maybe months?). Been meaning to blog it up, but hadn’t gotten the chance to flesh it out. The geologic map of the Commonwealth comes from Chuck Bailey of William & Mary, who gave me permission to use it for this project. Anyhow – do you think there … Read more
More pillow-like structures, seen in the Catoctin Formation, on the west side of the Blue Ridge Parkway about ten miles south of Interstate 64. Mini Sharpie for scale – what do you think? They don’t seem to be as strongly fracture-controlled as the Stony Man area “pillows.” But dang, they sure are small… Read the … Read more
Callan and three students visit a world-class outcrop of columnar jointing in Shenandoah National Park.
Callan visits a new outcrop of highly-sheared rocks in the basement complex of Virginia’s Blue Ridge province.
I saw this boulder lining a garden this past weekend down in Nellysford, Virginia, in the scenic valley of the Rockfish River draining the eastern slope of the Blue Ridge. It’s a piece of the Neoproterozoic-aged Catoctin Formation, a series of lava flows and associated rocks that erupted on the breakup of the early supercontinent … Read more